Glazes Tips

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How do I prevent glazes from settling ?

Glaze Settling

Have you ever had a glaze that kept settling to the bottom of your bucket? This is a common problem and may result in firing problems. When a glaze settles out, some of the heavier components of the glaze settle to the bottom of the container. If you try to use this glaze without thoroughly remixing you will be applying a glaze with key ingredients missing. A glaze stays in suspension due to the presence of various types of clays, such as bentonite, and/or gums, such as CMC. One common cause of settling out is the addition of too much water to the glaze, which dilutes the effect of the suspending agents and allows some of the glaze ingredients to settle out. Another possibility is the growth of bacteria which will consume an organic gum, such as CMC, and will lead to loss of suspension. To prevent bacteria growth do no return used glaze, which has been poured out of the original container, back into the original container. Also do not introduce possibly contaminated objects, such as brushes, into the original container. Storing glaze in a hot or sunny environment may also encourage bacteria growth. Freezing can also destroy the action of CMC. And glaze ingredients such as frits, nepheline syenite, soda feldspar and other slightly soluble materials slowly release sodium ions which can deactivate the suspension agent, making it ineffective.

   
How do I refire a glazed piece ?

Reglazing fired pieces

To re-glaze a fired piece you need to do one of the following:
Spray the piece with spray starch, let dry, then reglaze.
Spray the piece with sticky hairspray (usually the cheapest you can find), dry, reglaze.
Heat the piece first, with a heat gun or in the oven or kiln, then apply glaze, (my favourite).
Brush white (Elmer's) glue on, let dry, reglaze.
Microwave the piece for 30 seconds. (Some potters say this makes a huge difference, and the piece doesn't need to actually get or stay hot)
Add some suspension agent to the glaze (CMC gum or Bentonite.)
Add some detergent / shampoo to the glaze (baby shampoo is good because it doesn't foam)
To improve your odds further, wash the pot first with ammonia or detergent, wearing rubber gloves, and don't touch it. The oils from your fingers can prevent glaze from sticking.
And... Don't use too much of anything. If you get the coating too thick, you may prevent adhesion instead of encouraging it.

   
How do I prepare a glaze?

Mixing a glaze

Mixing a glaze:
Following the recipe, weigh out all the ingredients. Place all the glaze powder in a container at least twice its volume. Add approx. 100ml of water to every 100g of solids. Leave for 30 minutes to allow the glaze powders to absorb the water. This will break down any lumps and make for easier mixing. The glaze is now in slop form. Mix it thoroughly with a lawn brush, breaking up any large lumps as you go. Pass the glaze through an 80 mesh sieve into its permanent container, and use the lawn brush to push coarse material through the sieve. This ensures that all the ingredients are of a small particle size and will disperse. Stir the glaze to check its consistency. It should be like single cream, depending of course on your method of application.

   
How do I make my own glazes?

Balancing your glaze

Glazes need a balance of the 3 main ingredients: Silica, Alumina and Flux.
* Too much flux causes a glaze to run, and tends to create variable texture on the surface. The texture may vary from shiny, where the glass is balanced, to matt where the excessive flux oxides may form visible, possibly lumpy, crystals.
* Too much silica will create a stiff, white and densely opaque glass with an uneven surface. It will be glossy in spots, but the suspended silica can form crystals producing harsh dry surfaces. Too much silica will also inhibit the melting of a glaze, and the resulting surface will be roughly textured like sandpaper.
* Too much alumina causes a glaze to stiffen and tend towards opacity, again with a textured surface where it is dry in spots. Glazes will often have pinhole defects. Too much alumina can inhibit the melting of the glaze to the extent that a poor quality matt glaze results, one that looks matt but is prone to discoloration.

   
How do I prevent glazes from settling ?

Glaze Settling: remedy

If a glaze has settled out, but has not gone rock hard in the bottom of the container, you can add CMC or bentonite, if you happen to have it. But especially if you're dealing with commercial glazes you probably don't have that lying around. However, you can also use Epsom salts to suspend your glaze. Epsom salts can be readily purchased in most drug stores. First you need to create a saturated solution of Epsom salts by dissolving them in a cup of warm water until no more will dissolve. Then add this solution slowly and carefully to the glaze while continuously stirring the glaze. It should require less than approximately one teaspoon of Epsom salt solution per gallon of glaze. The quantity will depend on the severity of the problem. If a glaze has gotten too hard at the bottom to mix back up, first try my favorite glaze-stirring tool, a handheld kitchen stick blender. If that doesn't work, drain all the liquid off, work on dissolving the solid into the Epsom salt / water mixture, then add the rest of the glaze liquid back in.

   
How do I apply glaze?

Salt and pepper shaker holes

It is often difficult to keep salt and pepper shaker holes in the top from filling in with glaze during the firing. Next time insert short pieces of toothpick in each hole and put them in the kiln that way. The wooden toothpick will burn out during the firing but will help to keep holes clear of glaze.

   
How do I apply glaze?

Layering glazes

Some of the most interesting effects can be obtained by layering glazes. Try dipping an already glazed pot part of the way into another glaze. This greatly increases the chance of the glaze running, so don't try to doubling up the glaze all the way to the bottom of the pot. The best results usually come from trying a matt glaze over a gloss glaze. If the first layer of glaze isn't good and dry before applying the second, there is a good chance the glaze will crawl. A piece of bisque can only absorb so much water before it becomes saturated, so let it dry first. Anytime you notice the glaze cracking or peeling, it's probably too thick, so you're best off washing all the glaze off and starting over. Keep in mind that the glaze that falls off your piece can land on somebody else's and ruin it also.

   
How do I apply glaze?

Clear Satin Matt

Clear Satin Matt: Cone 4 - 7 Oxidation
Ferro Frit 4508 50.0
Potash Feldspar 20.0
Ball Clay 20.0
Magnesium Carbonate 10.0

   
What is a glaze?

Olive Matt/Soft Red

Helens Olive Matt/Soft Red
Cone 6-9
Reduction or Oxidation
Nephelene Syenite 75
Whiting 10
Dolomite 10
Bentonite 4
Silica 5
Copper Oxide 2

Comments: Cone 5-6 (electric kiln, oxidation) gives Olive Matt; Cone 9 (electric kiln, oxidation) gives Green/Orange Gloss; Cone 9 (gas kiln reduction) gives Soft Red Gloss.

   
How do I apply glaze?

Recipe: Bright Bronze

Bright Bronze
Cone 03
Oxidation
Ferro Frit 4508 8.8
Ferro Frit 4363 69.0
Kaolin 3.0
Potash Feldspar 9.0
Manganese Dioxide 7.6
Copper Oxide 1.0
Nickel Oxide 1.4
Titanium Oxide 0.2
Not suitable for tableware!

   
How do I use sand in glazes?

Using sand

For a little different technique you can use sand in combination with your glazes. It should be of a washed, fine grain and can produce a texture if applied to a piece with glaze.

   
How do I glaze an already fired piece again?

Refire a piece

If you find it necessary to glaze an already fired piece again, place it in your warm kitchen oven just long enough to get the piece slightly warm. Take the piece out and glaze immediately. The glaze will dry instantly and not slide off the fired surface.

   
How do I make a once-fire glaze?

Once-fire glaze

An addition of about 8% bentonite will easily convert a conventional glaze into a once-fire glaze.

   
How do I apply Matte glazes ?

Applying Matte glazes

Because Matte glazes do not flow during the firing process, it is necessary to not only necessary to apply them as evenly as possible, but is is also a good idea to rub each coat of colour lightly with your fingertips to even out brush strokes and eliminate any glaze pile up.

   
How do I apply glaze?

Clear to Milky Crackle

Clear to Milky Crackle: Cone 4 - 6 Oxidation
Lithium Carbonate (Toxic!) 25.0
Gerstly Borate 25.0
Zinc Oxide (calcined) 5.0
Calcium Flouride 5.0
Silica 25.0
Bentonite 2.0
Not suitable for tableware!

   
How do I decorate my ware?

Glaze Selection

As we become better at making beautiful forms we don't necessarily become better at achieving great glaze results. It seems so unfair! If you are serious about achieving great results your first step is to begin your own glaze journal today. It's important to do many different things right before you can be successful at glazing. First, consider what textures and colors you want the glaze to contribute to your finished form. Many art centers and community labs have test tiles you can observe before you commit to glazing with them. (If you are at a home studio, you will want to create your own test tile pattern with some of your favorite glazes.) We recommend you test one coat or two to see if it runs or changes colors when applied thicker. Also, test glazes on different clay bodies. If your facility has tiles, they probably indicate which glazes are stable and which glazes run. Glazes that run are not suitable for the outside of a piece. A glaze that runs can run off the pot and onto the kiln shelf making a huge mess. The same glaze can look very different on various clay bodies. Also, it may look different when applied thin vs. thick. An example is a copper red glaze called Oxblood, it's white when applied thin, red when applied thick - quite a difference.
The next step is choosing a suitable glaze for your clay body.

   
What is a glaze?

Essential components

The essential components of a glaze are silica, fluxes, and alumina. Silica is the basis of most glasses. The melting point of silica is over 3000oF, so we add fluxes to lower the melting point of the glaze. Alumina is needed to keep the glaze from becoming too fluid when it melts. Feldspar provides all three of these compounds and is the main ingredient in most cone 10 glazes.

   
What is blistering or flaking of a lustre ?

Blistering

Blistering
When a glaze has a 'bubbled', lava-like surface, this is called blistering. Some so-called 'lava glazes' are specifically formulated to blister. Normally this effect occurs when gases released from the glaze become trapped in the glaze matrix before they can escape and the glaze smooth over. This can be due to undefiring or overfiring.
Remedies:

· Fire the kiln slower

· Reduce kiln atmosphere less

   
How do I keep track of the number of coats of glaze?

Mixing: adding a marble to a jar of stain

You know how you get those spray can of household items with the bead inside to help mix them when you shake the can? You can do the same thing by adding a marble to a jar of colour before you mix it and it will help you complete the job.

   
How do I apply glaze?

Bleu de Ginette (Ginette's blue)

Bleu de Ginette (Ginette's blue)
Cone 04
Hardwood ash(washed)35%
Custer spar 14%
Frit #3134 25%
E.P.kaolin 14%
Lithium carbonate 12%
Bentonite 2%
Ultrox 15%
Cobalt oxide 5%

   
What are Alkalis?

Acidic oxides

Acidic oxides are oxides displaying acidic properties in ceramic fusions. They are Silica and phosphorus oxide. A number of other oxides, which are mostly dioxides, display some acidic properties in ceramic fusions. However they also display amphoteric properties which make it difficult to assess the unity formulae in which they appear. Those with strong acidic properties are:
Boron oxide
Titanium oxide
Tim oxide
Zirconium oxide
Cerium oxide
Vanadium oxide
Germanium oxide
Those with slight acidic properties are:
Antimony oxide
Arsenic oxide
Praseodymium oxide
Two other oxides display acidic properties in the raw state but change their oxidation during firing to become alkaline in character. They are:
Manganese dioxide
Lead dioxide
Manganese dioxide becomes manganese monoxide at 1080c. Lead dioxide is part of the lead compound called red lead. It becomes lead monoxide at 600c.

   
What is a glaze?

Clear Gloss 3

Clear Gloss: Cone 6 Oxidation
Nephelene Syenite 46.2
Gerstly Borate28.0
Silica 20.4
Kaolin 5.4
Bentonite 1.0

   
How do I apply glaze?

Satin Mottled Eucalyptus

Helens Satin Mottled Eucalyptus: Cone 5 Neutral Gas Atmosphere. Comment: Results in muddy color in electic kiln. Not suitable for tableware!
Nephelene Syenite 40
Whiting 25
Ball Clay 25
Lithium Carbonate 5
Silica 5
Copper Carbonate 2

   
Why are there craters in my glaze?

Craters in your glaze

If you have craters in your glaze, they can be saved by putting glaze in the craters and refiring to one cone hotter.

   
How do I test my glazes?

Types of test tiles: Round textured tiles

Using cookie cutters make round tiles with a decent sized hole a little in from one edge. Leave one half smooth & flat and use any method you like to create a raised pattern of some sort on the other half, so you get an idea of what the glaze would look like on an incised or impressed surface.

   
What is a glaze?

Talc White

Talc White
Cone 9
Oxidation or Reduction
Potash Feldspar 38.5
Silica 27.0
Whiting 16.3
Kaolin 2.9
Bentonite 3.0
Talc 12.5

   
What is blistering or flaking of a lustre ?

Blistering

can happen with glazes that boil a lot before maturing in the kiln. If the kiln isn't held at the top temperature long enough, bubbles that form in the boiling stage don't get a chance to heal
completely. This usually leaves little smoothed out craters in the glaze.

   
How do I remove the glaze ?

Remove the glaze

If you want to remove the glaze from the bottom of a piece to avoid slippage from stilts during firing, or you plan to felt bottoms, try removing the excess glaze with a piece of window screen placed on a table. Many keep a piece tacked to the corner of their work table at all times, just for this purpose.

   
How do I fire Reds?

Reds

Reds in glazes and underglazes are the hardest to accomplish and even the most experienced tend to purchase reds as they are so unreliable. Even the bought reds come up a lot better if put over a golden yellow underglaze. My advice is to buy these colours.

   
What is a crackle glaze?

Clear Crackle

Clear Crackle: Cone 6 Oxidation
Volcanic Ash 52.5
Ferro Frit 3134 28.0
Kaolin 5.3
Kaolin (calcined) 4.0
Bentonite 2.0

   
how do I apply glazes?

Recipe: Jade green ash glaze

Vert jade cendré (Jade green ash glaze)
Cone 04
Hardwood ash(washed) 36%
Custer spar 14.5%
Frit #3134 23%
E.P.kaolin 14.5%
Lithium carbonate 12%
Bentonite 2%
Ultrox 15.5%
Black copper oxide 3.5%

   
What are Peeling glazes?

Peeling

You may find that glazes are peeling from your ware. This is usually caused by too heavy and application of glaze over underglazes or one-strokes

   
What is Bubbled glaze

Bubbled glaze Description

Bubbled glaze can be caused by immature bisque, too heavy an application of glaze or by not firing the piece hot enough. Correct this by firing the piece to one cone hotter.

   
How do I apply glaze?

Best Brush on Technique

The best way to apply brush on glazes is to apply three coats with a large free flowing brush. The first coat should be applied going up and down the piece, the second going accross the piece, and the third as the first. This technique gives the most even application.

   
What is Pinholing?

Pinholing Remedy

Pinholing
When small dots of unglazed or depressed areas appear in the glaze surface, this is called "pinholing". Pinholing occurs when gases in the glaze and clay bubble up to the surface. The gas bubbles pop and a 'hole' appears, which doesn't fuse over.
Remedies:

· Fire the glaze higher

· Soak the kiln

· Wipe all dust off bisque ware

· Spray bisque ware lightly with water prior to glazing

   
How do I keep track of the number of coats of glaze?

Coat marker

A lead pencil is a handy tool for keeping track of the number of coats of glaze you have on a piece. You can write which step you are on over the glaze and the marks will fire out.

   
How do I make test tiles?

Storing Tests: Boards

Hammer rows of nails into a large board and hang the tiles on them. If you use long nails, each one will take several tiles. You can sort them by color, texture, etc.

   
How do I mix my glaze?

Mixing glaze tests: Let them sit

With glaze test batches, as with full batches, it is useful to let the glaze sit for 2 days to fully absorb, then re-mix.

   
How do I glaze my ware?

Take notes

Finally, remember to take notes while working with glazes. It's very disappointing to discover a wonderful glaze combination but not remember what it was. Two glazes when layered can make colors quite different from either of the two glazes alone, so if you didn't make a note, you may never know what you did!

   
What are some stoneware glazes?

Semi matt golden yellow

Semi matt golden yellow

Very intensive golden yellow. More red when thin, glossier when thicker. 1270oC with one hour at top temperature. Safe glaze.

potash feldspar NR 64,35
whiting 18,93
china clay 3,15
Albany slip 5,68
rutile 7,89
red ferric oxide 6,31

   
What is lustre?

Recipe: silver/gold clay paste

Lustre paste recipes: silver and golds
1. burnt umber 3
silver nitrate 1
+ vinegar

2. red clay 32
tin oxide 4
copper carb 10
silver nitrate 5
+ vinegar

   
How do I make my own glazes?

Basic glaze additions

Plus a glaze may include one or more additives:
1. Opacifiers – to make the glaze opaque instead of transparent. Examples: tin oxide, zirconium or Zircopax, titanium, zinc
2. Suspenders – to keep the glaze in suspension instead of settling out. Examples: bentonite
3. Colorants – to provide various colors. Examples: cobalt oxide, copper oxide.

   
How many coats do I apply?

Dry between coats

Before applying second and third coats of colour, be sure that previous coats have dried completely.

   
What is a glaze?

Cream Apricot

Cream Apricot
Cone 03
Oxidation
Potash Feldspar 30
Whiting 30
Kaolin 30
Titanium 10
*See Disclaimer*

   
How do I decorate my ceramics?

Pouring

Pouring is a technique which may be used if a work is too large to dip, or if there is just not enough glaze available. The ceramic object is held in one hand and glaze is poured over it as evenly as possible, until the whole surface is covered. With this method, overlapping is inevitable. If this is an issue with the glaze used, edges may be smothed over by rubbing with a finger. Hint: do not rub glazes with unprotected fingers if they contain toxic ingredients like lead, manganese or even copper! (Try rubber gloves.)

   
How do I make my own glazes?

What is a Flux?

To provide flux in the glaze, we need a material that contains one or more of the following:
Li2O=Lithium Oxide, comes from Lithium carbonate, Petalite, Spudomene
K2O=Potassium Oxide; comes from Potash Feldspar, frit
CaO=Calcium Oxide, comes from whiting, limestone, wollastonite (also provides SiO2), wood ash, bone ash, dolomite (also provides MgO)
MgO=Magnesium Oxide, comes from magnesium carbonate, dolomite (also provides CaO), talc
ZnO=Zinc Oxide, comes from zinc oxide
SrO=Strontium Oxide, comes from strontium carbonate
BaO=Barium Oxide, comes from barium carbonate
PbO=Lead Oxide (not used much due to toxicity)
Na2O=Sodium Oxide, comes from feldspar, FRIT, cryolite, nepheline syenite
TiO2=Titanium Dioxide, comes from pure titania, rutile
ZrO2=Zirconium Dioxide, comes from zirconium dioxide, zircopax, zirconium silicate
SnO2=Tin Oxide, comes from stannic oxide (SnO2 white), stannous oxide (SnO black)
B2O3=Boric Acid or Boron, comes from Colmanite, Gerstley Borate, CadyCal. Effective for lowering the melting point of a glaze.
If you've worked with glaze recipes at all, you probably recognize many of these terms, and can start to understand what they are used for.
You can take any glaze recipe, and break each ingredient down into its chemical composition as shown last week. An easy way to do this is by looking up the material in the DigitalFire database. DigitalFire database
Once you have the chemical composition of the ingredient, you can see what it contributes to the glaze. For example, is it primarily contributing silica, alumina, or a flux? Often a single ingredient contributes a combination of these. For example, Feldspar is primarily a combination of alumina and silica. And so is clay.

   
Where can I get glaze formulation software?

Unity Formula and Glaze Calculation Programs

You may have heard of something called a unity formula, or Seger formula. This is a way of expressing a glaze by the ratios of its oxides rather than % of raw materials. It is one of the primary methods used in analyzing glazes. I'm going to skip the detailed math. But the concept is that using information about each raw material, you create a ratio of the amount of flux to the amount of silica and alumina. These ratios can then be compared to ones which have been determined to work in a certain way at a specific temperature.
These calculations are very detailed and take a long time to do by hand. And because there are many factors that all interact, it would take a long time to learn each material and the effect it has on a glaze. So potters have created a variety of computer programs that simplify the analysis and formulation of glazes.
You can learn more by taking the self paced on-line tutorial called Glaze Teach. GlazeTeachThe writers of this tutorial offer a glaze calculation software program called Matrix.
Digitalfire, a website that explains glaze chemistry and sells a software program called Insight to help automate this glaze analysis process.

   
How do I wax my lids?

Waxing: Lids

We use wax to keep lids from becoming glazed to jars. Stoneware can distort in firing, so we usually fire lidded containers with their lids on. Otherwise, the jar opening might go out of round, and the lid may not fit well. Wax all the points where the lid and jar come into contact. It's a good idea to run the wax about 1/8" back from the line where they meet both inside and outside the pot in case the glaze runs.

   
What are some stoneware glazes?

Recipe: Silky matt mushroom-colored

Crystal glazes: Silky matt mushroom-colored
A good glaze based on zinc and barium. Very smooth. Not too thick. 1260-1280oC with 1/2 to one hour at the top temperature.
potash feldspar NR 44,67
whiting 4,67
zinc oxide 15,79
barium carbonate 16,26
china clay 13,93
rutile 4,67

   
What is a glaze?

Clear Gloss 3

Clear Gloss
Cone 9 - 10
Oxidation or Reduction
Potash Feldspar 23.0
Whiting 11.0
Talc 15.0
Silica 13.0
Bone Ash 4.0
Kaolin 15.0
Ball Clay 13.0

Comment: good for tableware.

   
How do I store my test tiles?

Storing Tests: Boxing the duds

Get a large box to keep those you will never want to use again! Never throw glaze tests out... You THINK you will always remember the duds, but it is surprising how fast you forget the results even if you remember testing a certain glaze.

   
How do I apply glaze?

Mottled brown ash glaze

Edouard's Brun veiné cendré (Mottled brown ash glaze) Cone 4. Thank you to Edouard Bastarache for supplying this glaze recipie.
Nepheline/Syenite 25%
Hardwood ash(washed) 20%
Silica 20%
Ball clay 5%
Gerstley borate 30%
Bentonite 2%
Ultrox 15%
Cobalt oxide 5%

   
How do I make my own glazes?

Understanding %'s

Glaze recipes are typically expressed by listing each raw material and its % by weight. The percentages add up to 100 Usually colorants and sometimes other additives (such as bentonite for suspension) are not included in the 100%, they are added on afterward.
Example:
Cone 6 Clear Base Glaze

Wallastonite 10%
FRIT 3134 30%
Kaolin 25%
Flint 15%
F-4 Feldspar 20%
Total 100%
Add 4% cobalt oxide for a deep blue
To mix this glaze, you take the total number of grams of dry material you are making, multiply by the % to get the grams of each material to add.
Example:
To make 1000g of glaze
Wallastonite = 10/100*1000=100 grams
FRIT 3134=30/100*1000=300 grams
Kaolin = 25/100*1000=250 grams
Flint = 15/100*1000 = 150 grams
F-4 Feldspar = 20/100*1000 = 200 grams
To double check, add up all the grams and make sure they equal 1000.
Then add 4/100*1000 = 40 grams cobalt oxide
This is as far as many people go. They make the glaze, test it, and often are unhappy with the results. We need to understand why!

   
How do I decorate my ware?

Recipe: Semi matt dark blue

Crystal glazes: Semi matt dark blue
A glaze with zinc. You must not apply it too thick. 1260-1280oC with one hour at the top temperature. Does not need a slow cooling. Small or no crystals.
potash feldspar NR 65,90
dolomite 16,15
zinc oxide 17,95
red ferric oxide 5,00
cobalt oxide 2,00

   
What is a glaze?

Copper Green

Copper Green
Cone 03
Oxidation
Kaolin 14
Dolomite 8
Potash Feldspar 64
Whiting 16
Tin Oxide 4
Copper Oxide 1.2

   
How do I glaze my ware?

Pouring glazes

Pieces that are too large to fit in the glaze bucket can be poured. Hold the piece over a large bowl and pour glaze onto the pot. Try to get the glaze layer even by pouring steadily and rotating the piece. Again, any overlapping areas will usually show, so you can use this decoratively. For cylindrical forms or mugs, it's usually best to glaze the inside by pouring. Pour the glaze into the pot and slowly rotate it as you pour it out. The outside then can be glazed after the inside dries.

   
How do I glaze the inside of my salt and pepper shakers?

Glazingsalt and pepper shakers

The inside of salt and pepper shakers should be glazed too. If you have trouble getting the glaze inside, use a squeeze bottle and force it in. You may also thin glaze with water to help with the job of pouring it in. Be sure to use a toothpick or tool to clear holes in top

   
How do I make a test tile?

Types of test tiles: Extruded "T"

“T" shaped tiles made from an extruder. Make one side of the leg of the T smooth, the other side a texture. Do the three dips with the leg of the T. Lay it upside down (on the top part of the T) to fire, which will help to catch runny glaze, or if you glaze the whole inside L also give you an idea of what the glaze acts like on a flat surface.

   
What are some crude glazes

Stoneware Crude glazes

We can create crude glazes from single materials. Borax can be dusted on a piece and fired to make a runny low-fire glaze. Galena (raw lead ore) was often used in the same way on folk pottery. Work fired in wood burning kilns is often glazed by the wood ash that flies along with the draft of the kiln. Depending on the build up of ash during the firing this creates from a light sheen to a thick runny glaze on the shoulder of the ware. Salt or sodium bicarbonate (baking soda) can be used to create vapor glazes. The salt or soda is thrown or sprayed into the kiln at peak temperature to create sodium vapor. The vapor condenses on the ware and combines with the clay to create a glaze. Sufficiently low temperature clay can be mixed into a slip and used a glaze on high fired pottery. Also, some feldspars melt at low enough temperatures to make crude cone 10 glazes. Some of these techniques are still used by potters who admire their simplicity and natural earthy aesthetic.
All of the above methods of glazing have inherent difficulties. Dusted on glazes can only be used on nearly horizontal surfaces. Wood firing is time consuming and labor intensive, and except in certain areas of the kiln, the deposit of fly ash is incidental--it makes beautiful accents, but it hardly qualifies as a functional glaze. Vapor glazing also glazes the entire interior of the kiln and all the props used to support the ware which considerably shortens their lives. Most of these glazes have serious flaws from a functional stand point. They make be crackled, excessively runny, or present problems in applying the glaze to the ware. The glazes that we'll be using are combinations of raw materials carefully combined to avoid these problems. They are applied as liquids to bisqueware and fired to cone 10 to melt them.

   
Why am I having trouble with red glazes?

Application

During the formulation of red glazes, there are certain minerals hard for manufacturers to eliminate. One of these is manganese which produces a black speck in the finished piece.
Black specks in red glazes can also be caused by dirty bisque so be sure to inspect pieces before applying reds.
To get the best results with reds, you should apply glazes of the same family on bisque.
Red glazes should not be thinned when applying three coats of even coverage. Some teachers even recommend four to five coats.
Most of the problems with red glazes occur during the firing process.
The recommended bisque you should use for red glazes is that which has been fired to cone 04 or 05.
You should not fire raw clay bodies with reds.

   
Ho do I avoid pitting and pinholes?

To avoid pitting and pinholes

To avoid pitting and pinholes in your glaze, be sure that your greenware is free of dust before applying glaze. A damp sponge will help to do the job.

   
How do I apply glaze?

Transparent Flowing Glaze

Transparent Flowing Glaze
Cone 04
Oxidation
Lead Bisilicate (Toxic!) 76.5
Kaolin 8.0
Nephelene Syenite 15.5
Comment: variations can be achieved by adding small amounts of oxides and carbonates ( 2-5%).
Not suitable for tableware!

   
What are ceramic glazes?

Glazes

Ceramic glazes are a fascinating combination of chemistry and art and can be dangerous if not handled with care and experience. There are so may iterations of ceramic glazes that you can truly achieve any color, patina or effect that you want but take care - using metals, chemicals and other components can be dangerous - especially in your home and without proper containment or protective gear. Still, have fun finding your signature glaze and making your ceramic piece stand out from the rest.

   
What is a lead glaze?

Leadfree glaze testing

Using lead free glazes:
Make test firings of the body and glaze to their recommended cone number, first the unglazed body, then the glazed bisque.
Use witness cones placed near the ware to be sure the proper cone number was reached. Differences may exist between the Kiln-Sitter and a witness cone or from the top to the bottom of the kiln. Firing with a controller to a cone number or a temperature may not be adequate.

   
Why do glazes coming out with a grainy surface?

Glazes coming out with a grainy surface,

If you have a problem with glazes coming out with a grainy surface, you may be applying them too thin. The best way to correct this problem is to warm piece slightly and apply another coat, then re-fire to proper cone.

   
What are some stoneware glazes?

Black, semi glossy oilspot

Oxidation:

Black, semi glossy oilspot

Rather thick or it will be no spots. 1260-1280oC with one hour at the top temperature.
Albany slip (the real thing) 70,74
petalite 16,08
ochre 8,36
red ferric oxide 4,82

   
How do I make my own glazes?

Basics of a glaze

Every glaze is made of the following 3 materials:
1. Silica – Creates glass. Examples: quartz, flint, pure silica
2. Alumina – Stiffens the glaze so it doesn't slide off the clay. Examples: clay (kaolin, ball clay, or fire clay), alumina hydrate
3. Flux – Causes the glaze to melt at a low enough temperature to be used in ceramics. Examples: feldspar, whiting

   
What is bone ash?

Bone ash as an opacifier

Bone ash is used in glazes as an opacifier. It can be used to assist tin oxide so that less tin oxide is required, especially where a less shiny surface is acceptable. It creates an attractive soft mottling and also encourages the glaze to flow away from modelled high spots making relief decoration more effective.

   
How do I decorate my ceramics?

Metallic oxides

The color that a metallic oxide gives to a glaze depends a great deal on the composition of the glaze, the firing temperature, and the atmosphere in which it's fired. Many of the colorants used to make bright colored glazes at low temperatures vaporize well before cone 10, so they can't be used in high fired glazes. The colors of cone 10 glazes are mostly earthy--keep this in mind as you design your pieces. Very literal or painterly decorations that require a lot of detail and color contrast are hard to create on stoneware. Cone 10 glazes are quite beautiful--the firing can add accents that range from striking to subtle. Be patient as you learn to use them to their full potential.

   
How do I apply glaze?

Recipe: Aqua Blue Dry Glaze

Aqua Blue Dry Glaze
Cone 2 - 4
Oxidation
Nephelene Syenite 40.0
Barium Carbonate (Toxic!) 30.0
Ball Clay 15.0
Zinc Oxide 5.0
Black Copper Oxide 4.0
Comment: Fast cooling helps preserve color.

   
t is a Glossy cobalt blue crystal Glaze recipe?

Recipe:Glossy light to turquoise blue

Crystal glazes: Glossy light to turquoise blue
A popular crystal glaze based on zinc and lithium. Too thick it will run a lot. Spray the glaze thinner near the bottom of the pot. 1260oC with 3/4 to one hour at the top temperature. Does not need a slow cooling. Also try with 2% stannic oxide. potash feldspar NR 28,50
quarts (flint) 34,00
dolomite 3,53
zinc oxide 19,00
barium carbonate 4,35
china clay 3,26
lithium carbonate 7,34
rutile 2,17
cobalt carbonate 0,19
copper oxide 1,09

   
Can I mix bisque and glaze in the same firing?

Black specks

Black specks in the ware are usually caused by organic materials not completely burned out in the bisque firing. They work their way to the surface during a glaze firing

   
What are some crystalline glazes?

Basic+oxides

Crystalline Glaze
Cone 6 - 10
Oxidation
Base Glaze
Potash Feldspar 35.0
Calcite 12.0
Zinc Oxide 24.0
Silica 22.0
Kaolin/Eckalite 5.0

Add:
Nickel Oxide 2.0 for blue
Red Iron 4.0 = Manganese Dioxide 6 for brown
Copper Carbonte 1.0 - 2.0 for green
Comment: slow cool from maximun temperature to about 1000 C in 3 - 6 hours

   
How do I apply glaze?

Smooth White Matt

Smooth White Matt: Cone 4 - 7 Oxidation
Ferro Frit 4616 60.0
Nephelene Syenite20.0
Ball Clay 20.0

   
What are some tips on satin glaze ?

Satin glaze

Since a satin glaze is one with a soft sheen which moves only slightly during firing, you may be able to create your own by applying alternate coats of transparent matte and a coloured gloss glaze.

   
How do I apply Lustres?

remove mistakes when using gold

It is possible to remove mistakes when using gold or lustres by using a ‘gold eraser'. It looks like a normal eraser but is chemically formulated to do the job as well as containing an abrasive.

   
How do I remember the finished result of a glaze?

Test tiles

You can make your own test tile chart for home use. I suggest test tiles be made and fired before glazing any piece with that glaze.
Simply cut rectangles approx. 4"X2", you can texture with lines carved into the clay, (This will give you an indication of the glaze flow). Bisque.
When applying your glaze, brush on in order 1 coat, 2 coats, 3 coats (this helps you gauge desired thickness).
Of course you can apply slips or underglazes to unbisqued tiles for further tests. I suggest using a variety of clays for each test, as the body can radically affect the glaze results.
Put holes in the corners of each tile, for hanging. Clearly mark the back of each tile eg C/W twe. (the clay body), Copper Red 1(Glaze used), the date can also be a handy reference to your notes.
Also keep detailed writen or computerised notes on all tiles. To the full recipe, add the firing details, description of the finished glaze and conclusion to these notes, you will find them invaluable in the future, so keep them safe.
A great Book for the experimentation of glazes is:
GLAZES And Glazing Techniques by Greg Daly. Kangaroo Press. ISBN:0-86417-502-7

   
How do I avoid pinholes?

To avoid pinholes

During the glazing process, you may notice some pinholes appearing. To avoid any problems after the piece is fired, be sure to take the end of your brush and work your glaze into the holes, or simply rub your fingers over the glaze surface, gently.

   
What are some common glaze faults?

Shivering Remedy

Shivering
Shivering occurs when a glaze contracts lees than the clay body. Parts of the glaze crack and move against each other lifting off from the clay surface. This can be so bad that pieces of glaze will actually jump off the surface.
Remedies:

· Reduce silica in the clay body

· Reduce silica in the glaze

· Reduce alumina in the glaze

   
What are some Earthenware Glazes?

To keep glaze from clumping

To keep glazes from clumping: Epsom Salts solution: by volume 3 parts hot water (helps dissolve) to one part Epsom Salts (available drug and grocery stores-cheaper than pottery suppliers). Add 1 1/2 cups of Epsom Salt solution to 4 gallon batch of glaze.

   
How do I make my own glazes?

Making a basic glaze

To make a glaze, we need to find sources of Silica, Alumina and a flux which are convenient to use, in a form that does not dissolve in water. Glaze materials can be broken down into their chemical compositions, and from there we can see what the effect of each material will be.
To provide silica in the glaze, we need a material that contains:
SiO2=Silicon Dioxide, comes from flint, quartz and pure silica.
To provide alumina in the glaze, we need a material that contains:
Al2O3=Aluminum Oxide, comes from feldspar, cryolite, clay.
FLUXES
Silica and alumina would create a glaze if fired hot enough. However, ceramic kilns do not reach the temperatures required. Therefore, we need to add fluxes, which lower the melting point.

   
What safety aspect should I keep in mind when working with glazes?

Barium alternatives

In glaze recipes calling for Barium Carbonate, substitute 1.18 parts of non-toxic Barium Sulphte for 1 part of the toxic Barium Carbonate. Many glazes will be unaffectd by the substitution. Others may be better or worse - test!

   
What is a glaze?

Tenmoku Red

Tenmoku Red
Cone 03
Oxidation
Potash Feldspar 39
Whiting 15
Ball Clay 12
Silica 200# 25
Red Iron Oxide 9
*See Disclaimer*

   
What is Raku?

Rusty Red Black Fire Glaze

Salvatoris Rusty Red Black Fire Glaze
Copper Carbonate 60.0
Borax 40
Sodium Bicarbonate 40
Cobalt Carbonate 5.0

Comments:
Bisquefire work to 1100o C
Mix glaze same day as firing
Apply glaze thickly
Dribble glaze on thickly for effects

   
How do I glaze an already fired piece again?

Glaze an already fired piece again,

If you find it necessary to glaze an already fired piece again, place it in your warm kitchen oven just long enough to get the piece slightly warm. Take the piece out and glaze immediately. The glaze will dry instantly and not slide off the fired surface.

   
What are some different ways to apply my glaze?

Different glaze effects

For an interesting effect in an electric kiln, add between 3% and 10% rutile to any glaze. Your glaze will often get a nice mottled texture which is similar to reduction glazes. Rutile can also affect the colors in an interesting way. We also sell a product called a texturizer which contains rutile and can be brushed on to specific areas, over or under your glaze. By painting designs on with this, you will get a very subtle effect where the texture changes. Look under "additives".

   
How do I apply glaze?

Decorating the yard with ceramics

Decorating the yard with ceramic pieces is always a lot of fun, but many forget to prepare the inside of pieces. Be sure to glaze the inside of all your pieces as well as staining outside. This will help to protect the piece from moisture and make the decoration on the outside last a lot longer. If you do not protect the inside moisture can get into the bisque and push the decoration off the outside, usually in the form of chipping.

   
How do I test my glazes?

Mixing glaze tests: Knowing your level

Many people use old blenders or stick blenders for mixing test batches. They mark off with a magic marker where enough water for a 100g test comes, so they can just put in the water and add ingredients as they are weighed out. (Tip: Use a piece of masking tape until you are sure enough to draw your line with a magic marker.) Another reason to mark where a 100g or a 200g batch of wet glaze comes, is so you can can add that much base glaze before adding colorants or other ingredients.

   
What is a glaze?

Feldspar

Typically when formulating a glaze we'll start with a feldspar, add a flux to lower the melting point, add clay to help keep the raw glaze in suspension and to help make the glaze adhere to the bisqueware, and add flint to keep the glaze from crazing (crackling). Colorants and opacifiers are added after the base glaze has been tested. Creating new glazes takes long hours of mixing small batches and firing them on test tiles. The choice of ingredients and proportions can be guided by calculations or by using rules of thumb and trial and error. Usually it's a little bit of both.

   
Why should I save those little dabs of glaze ?

Save little dabs of glaze

Be sure to save those little dabs of glaze left oven in a jar. You can pour the excess in a larger jar and save it for later. You probably would not want to use it as a decoration after mixing all the colours together, but you can use it inside of something such as a flower pot where it will not be seen.

   
What is a glaze?

Tomato Red

Tomato Red
Cone 03
Oxidation
Potash Feldspar 42.52
Slica 200# 18.9
Kaolin 6.3
Magnesium Carbonate (Light) 5.51
Whiting 6.3
Bone Ash (Synthetic) 10.24
Red Iron Oxide 10.24
*See Disclaimer*

   
How do I apply glaze?

Recipe: Bleu de Sorel (Sorel blue)

Bleu de Sorel (Sorel blue)
Cone 04
E.P.kaolin 20%
Frit #3134 78%
Bentonite 2%
Zircopax 18%
Cobalt carbonate 4%

   
What is Dunting?

Dunting in thin pieces

If we use a low expansion glaze inside a thin-walled piece, this can cause dunting. The body contracts around the glaze--if the glaze won't shrink enough it can crack or break the pot. This most often happens when we glaze the inside but not the outside of a piece.

   
How do I clean the bottoms of my pieces for firing?

Removing glaze from base

You should keep a piece of old carpet (not shag) handy for removing the glaze from the bottom of pieces you may want to dryfoot. It acts somewhat like sandpaper but not as abrasive.

   
How do I apply glaze?

Semi-matte/satin glazes Smoothing

It is a good idea to smooth coats of semi-matte or satin glazes with finger tips between coats.

   
What are some stoneware glazes?

Recipe: Blue and yellow crystals

Crystal glazes: Blue and yellow crystals
A semi glossy crystal glaze based on frits and zinc. It tends to run not too much, but spray it thinner near the bottom of the pot. 1260oC with ¾ hour at top temperature. Usually it behaves very good. The crystals can be very complex and large. Use it alone or together with one of my 6713-glazes. If you reburn it the crystals will be smaller.
boric frit MOK1 17,50
zinc barium frit 90420 26,40
quarts (flint) 23,10
zinc oxide 22,10
china clay 4,30
bentonite 3,30
rutile 3,30
cobalt carbonate 1,30
manganese carbonate 2,00

   
What is Celadon?

Celadon Atlas

Edouard's Celadon Atlas #1
Cone 9
Custer spar 30%
Hardwood ash (washed) 30%
Silica 10%
Ball clay 2%
Atlas-Brown Dust 30%

Comment: Atlas Stainless Steels is a maker of stainless steel sheets located in Tracy,Quebec.
This dust comes from the anti-pollution system of their melting department
Its general formula is as follows:
F2o358%
Cr2o314%
Nio.5%
Mno7%
Cao.7%
Mgo6%
Sio2.3%
Thank you to Edouard Bastarache
for supplying glaze recipie

   
What is a glaze?

Matt Textured Rust

Helens Matt Textured Rust: Cone 5 Neutral Gas Atmosphere. Not suitable for tableware *See Disclaimer*
Potash Feldspar 15
Nephelene Syenite 20
Dolomite 25
Kaolin 5
Silica 15
Barium Carbonate 5
Copper Carbonate 2

   
how do I apply glazes?

Metallic Copper

Metallic Copper
Cone 06
Raku Reduction
Copper Carbonate 80.0
Ferro Frit 4110 16.0
Kaolin 11.0
Frit 4064 (Toxic!) 3.0

Comments: beware of lead toxicity! Bisque with glaze to 1000 C, then raku to 850 - 880 C.
Not suitable for tableware!

Mix glaze same day as firing
Apply glaze thickly.
*see disclaimer*

   
How do I apply glaze?

Spraying

Glaze can also be applied by spraying. The pot is rotated in the spray booth as the spray is applied. Spraying is most effective for adding accents or shading. The glaze can be applied heavily to one area of the piece and feathered out to a light application elsewhere. Brushing isn't recommended for applying high-fire glazes. It's difficult to get the glaze thick enough. A brush is handy for touching up spots where the dry glaze has chipped off rims or to fill in small areas. Build up the glaze nice and thick, and rub off the excess after it dries.

   
How do I decorate my ware?

Airbrushed: Protect a piece

You can protect an airbrushed piece that smears easily by spraying on a light coating of glue before firing. You can then handle piece for placement in kiln without worry.

   
How do I apply Lustres?

Lustre resist

Lustre resist is a product that is used for blocking out areas that you do not want to add lustre to. It fires away.

   
What is Spill base ?

Spill base description

Spill base is that class of glaze that is applied over, under or between application of other coloured glazes, causing them to blend and form spill effects when fired.

   
How do I apply Metallic glazes ?

Metallic glazes

Metallic glazes flow quite a bit during firing so the first coat is the only all-over coverage, followed by the last two which should be ¼” up from the bottom of the piece. Metallic glazes are water soluable and may be thinned with water to ease application. The metallic family of glazes are marketed under a variety of names, but the term defines those colours that contain metallic particles which flow into detailed areas to form shimmering designs. When firing metallic glazes, you get better results by firing them one cone hotter than other glazes and allowing a longer soaking period.

   
Can Crackle glazes be used for food?

Crackle glazes: uses

Crackle glazes are for decoration only and are not recommended for use on food or any container that will be exposed to water.

   
How many coats do I apply?

apply glaze

It is best to apply glaze in a cross-hatch fashion to eliminate missing any areas.

   
What is ‘low-fire’ ?

‘low-fire'

The types of glazes used in hobby ceramics fall under the ‘low-fire' category since the kiln only uses the medium temperature ranges to mature the glazes

   
How do I apply crystal glazes?

applying crystal glazes

When applying crystal glazes, it is usually recommended first that you do not mix or stir the jar of colour. The first two coats of colour should be taken from the top part of jar that contains few crystals. The third and final coat should be applied by dipping into the bottom of the jar, picking up crystals on the brush and applying to a piece.

   
how do I apply mother of pearl

Applying Mother of Pearl

Most pearl lustres are applied in a criss-cross fashion, using three coats, eg one coat down one coat accross and one on a 45% angle.

   
How do I glaze my ware?

Glaze Application:Dipping

Glaze Application
Dipping: A pot is immersed in the glaze for a few seconds. The pot can be dipped again for a further couple of seconds, know as “double dipping”. This double layer of glaze can produce different fired results and can create a range of decorative effects.

   
How do I apply glaze?

Recipe: Matt Clear

Matt Clear E/W
Cone 04
Oxidation
Potash Feldspar 46.8
Silica 10.0
Colemanite 11.0
Whiting 13.0
Barium Carbonate (Toxic!) 13.0
Zinc Oxide 4.0
Not suitable for tableware!

   
How do I decorate my ceramics?

Glaze journal

You can tell who is serious about getting good glaze results by seeing who tracks their results. Just like in business. If you want to get serious, get out the glaze journal and record what you are doing when you glaze your work.

   
How do I achieve a brighter fired gold?

Burnished golds

Burnished golds are those that must be polished when removed from the kiln.

   
How do I fire lustre?

firing lustre

When firing lustre, do not place the piece to be fired directly on a hot bottom or shelf as the radiation of the heat will drive the lustre away.

   
how do I get the best results in glazing?

Brush Loading

For best results in glazing, be sure to load brush well with colour.

   
What are Alkalis?

Alkalis

What are Alkalis?
Alkalis are the opposite of acids, potters call the glaze and body fluxes their alkalis. These are the non-colouring metal oxides which react with the acids in the presence of heat to produce silicates(glasses).
The so-called strong alkalis are:
Lithium oxide
Sodium oxide
Potassium oxide
Which are soluble in water. The weaker alkalis are partly referred to as aldaline earths or by the more general name of bases. They are:
Beryllium oxide
Magnesium oxide
Calcium oxide
Strontium oxide
Barium oxide
Zinc oxide
Cadmium oxide
Lead oxide
Bismuth oxide
They are not necessarily weaker in ceramic fusions but are less actively soluble in water.
They do not give the same bright colour response in glazes as the strong alkalis.
Alkalis release negatively-charged hydroxyl ions when dissolved in water. They have a sting and a re corrosive in a similar way to acids whilst being neutralized by the substances they meet. The soluble alkalis, soda ash and sodium silicate, are used to deflocculate clay for slip casting.

   
How do I make test tiles?

Types of test tiles: Extruded Squares

Extrude a hollow square or hexagonal form to create a long tube. This gives 4 surfaces to do different things to. One side is scratched with a fork or a serrated rib for texture. One side receives black underglaze, one red underglaze, etc. and the last side left plain. (You can vary this, add oxide lines to see how they react) Slice into sections about 3 inches long and punch holes.

   
What are some stoneware glazes?

Blue Green

Blue Green
Cone 10
Oxidation or Reduction
Potash Feldspar 35
Whiting 10
Dolomite 20
Bentonite 5
Silica 200# 30
Rutile Flour 10
Cobalt Oxide 1.5

   
What are some crystalline glazes?

Silky Matt Crystalline

Silky Matt Crystalline. Cone 9 Oxidation.
Potash Feldspar 25
Zinc Oxide (Calcined) 25
Silica 20
Whiting 15
Ferro Frit 3110 10
Lithium Carbonate (Toxic!) 5
Comments: Add colorants: Cobalt Carbonate (0.2-1%); Copper Carbonate (0.1-7%); Manganese Dioxide (1-5%); Red Iron Oxide (0.2-5%); Nickel Oxide (1-2%).

   
What is a glaze?

Translucent Clear

Translucent Clear: Cone 6 - 7 Oxidation Not suitable for tableware!
Potash Felspar 25.0
Calcite 20.0
Silica 35.0
Ball Clay 25.0
Ferro Frit 4508 20.0
Barium Carbonate (Toxic!)10.0

   
How do I apply glaze?

Brilliant Blue Satin

Helens Satin Brilliant Blue Cone 6-7
Neutral Gas Atmosphere
Potash Feldspar 15
Nephelene Syenite 20
Zinx Oxide 20
Silica 5
Barium Carbonate 40
Cobalt Oxide 0.7
Not suitable for tableware!

   
How do I apply glaze?

Maiolica Glaze

Maiolica Glaze
Cone 07-06
Oxidation
Ferro Frit 4364 (Lead Bisilicate!) 31.5
Ferro Frit 3271 (Borax Frit) 68.5
Kaolin 10
Tin Oxide 10

   
What is Crazing?

Crazing Description#2

Crazing is a very common flaw--the glaze will appear cracked. Most materials will expand when heated and contract when cooled. We're all familiar with the expansion joints on bridges which allow the road bed to expand and contract without buckling or cracking. A glaze and the clay body it covers will typically expand at different rates as they are heated. If the glaze has a much higher rate of expansion than the body, the glaze will craze. Picture a pot in the kiln at cone 10. The glaze is a very thick liquid (like melted taffy) spread over the surface of the clay. As the pot cools, the clay and glaze contract. But if the glaze wants to contract more than the clay, it builds up stress until it cracks. Usually a glaze will craze before it comes out of the kiln, but it can take a week or so to release the stress. Often we'll hear still warm pots pinging as they come out of the kiln--this is the glaze slowly crazing. Crazing can be used intentionally as a decorative technique. In this case we call i crackling. Realize that crazing is not so much a flaw of the glaze than it is of the combination of glaze and body. A glaze that doesn't craze on one clay body may very well craze on another. We usually try to remedy crazing by adding more silica to the glaze. Silica has a low coefficient of expansion, so adding it to the glaze makes it contract less.

   
firing plates, position ?

Glaze the bottoms

If your pieces such as vases, cups, etc., require that you glaze the bottoms, let them stand to dry on stilts. This will allow the air to reach them easily and will prevent a drip line.

   
What brush should I use for glazing?

brush for applying glazes.

Most people have a favourite brush for applying glazes. However, almost any soft bristle brush will work. Normally they are at least ¾” wide and range up to the mop style.

   
How do I glaze my ware?

Dipping

Dipping is as easy as it sounds. Tongs can be used to hold the piece as we immerse it in the glaze. Be sure to touch up the marks from the tongs once the glaze has dried. Usually there will be a few drops of glaze sticking to the wax on the bottom of the piece. Clean these up with a damp sponge. A piece can also be dipped half way, allowed to dry and then dipped again to glaze the other half. With most glazes the area where the two coats overlap will have a slightly different color, so the overlap can be used as a decoration.

   
What are some stoneware glazes?

Glossy yellowish with blue crystals

Crystal glazes: Glossy yellowish with blue crystals
One of my most popular crystal glazes based on zinc and lithium. Too thick it will run a lot, but it can be controlled very exactly after a few tests. Always spray the glaze thinner near the bottom of the pot. 1260oC with 1/2 to one hour at the top temperature. Does not need a slow cooling. You can also try other combinations of coloring oxides.
potash feldspar NR 27,60
quarts (flint) 32,20
dolomite 3,48
zinc oxide 18,70
barium carbonate 4,44
china clay 2,75
lithium carbonate 6,82
rutile 4,01
cobalt oxide 1,06

   
What is a glaze?

High/Low fire-Your choice

Let's consider the pros and cons of high fired glazes versus low fired glazes: Pottery fired to Cone 10 or higher is generally safe for food. As long as the clay has been fired to Cone 10 and vitrified, it should be safe from bacteria. Low fired pots can potentially capture bacteria in cracks in the glaze or clay body since it's not vitrified. So, if you are making utilitarian pottery to be used with food, you need to use a high fired clay body and glaze. Some potters prefer stoneware glazes because the variations are so diverse. You could spend a lifetime experimenting with some glazes. You don't have to know chemistry to be a fine potter, but to really progress with glazing you need to learn as much as you can. Begin looking at glaze recipes in terms of the role of each ingredient. Notice which oxides are in the glazes you are using. You quickly learn patterns. Each compound has a job to do in a glaze. Learn about the chemicals and you can begin to control the results.

   
How do I decipher The size of crystals ?

For special effects

For special effects, you can control how the crystals will run on a piece by actually placing them in certain areas. If, for example, you want the crystals to run down only from the top rim of a piece, simply apply the normal number of coats of glaze and add just enough crystals around the top rim to obtain the desired effect.

   
What is a Majolica glaze?

Recipe Majolica

Majolica: Frit 4064 74
Kaolin 10
Whiting 2
Silica 4
Tin Oxide 10
Good solid white fire to cone 6

   
what is a Olive Matt/Soft Red glaze recipe?

Olive Matt/Soft Red

Helens Olive Matt/Soft Red
Cone 6-9
Reduction or Oxidation
Nephelene Syenite 75
Whiting 10
Dolomite 10
Bentonite 4
Silica 5
Copper Oxide 2

Comments: Cone 5-6 (electric kiln, oxidation) gives Olive Matt; Cone 9 (electric kiln, oxidation) gives Green/Orange Gloss; Cone 9 (gas kiln reduction) gives Soft Red Gloss.
*See Disclaimer*

   
What is a Copper Red glaze recipe?

Copper Red #2

Copper Red
Cone 9 - 10
Reduction
Nepheline Syenite 206.97
Colemite 46.35
Whiting 40.20
Copper Oxide 1.45
Tin Oxide 3.75
Silicon Carbide 1.13

Thanks to Giordano Andrew Voeks
of Hawaii for this glaze.

   
How do I apply glaze?

Brilliant Ink Blue

Steve's Brilliant Ink Blue Cone 4 Oxidation or Reduction
Ferro Frit 3134 50.0
Potash Feldspar 20.0
Ball Clay 20.0
Zinc Oxide (dense) 10.0
Cobalt Carbonate 1.5
Cobalt Oxide 1.5.

   
What is Bat wash?

Waxing

We need to wax the bottom of the piece. Any part of the piece that will come within 1/4" of the kiln shelf should not have any glaze on it. This is called dry footing. Melted glaze acts like a glue when it comes between two surfaces. If there is any glaze on the bottom of your piece, it will become glued to the kiln shelf in the firing. At worst it will have to be removed with a hammer and chisel, and the kiln shelf will be ruined.

   
How do I fire Ceramic glaze ?

Bubbled glaze Remedy

If you discover bubbles in your glaze after firing, you may be firing too rapidly. Slow down your firing cycle. Gasses and air bubbles must be allowed to escape during the firing process by soaking the glaze with a longer firing.

   
How do I apply Lustres?

Cleaning for lustres

The object to which you are applying the overglaze must be thoroughly clean. Use a lint-free cloth and alcohol as the cleaner.
If you use alcohol to clean pieces before applying overglazes, be sure to allow plenty of drying time before starting to apply colour.

   
How do I decorate my ware?

Crackle glazes: varieties

Crackle glazes are available in a variety of colours and may be in matte, gloss or transparent varieties.

   
How do I apply glaze?

Matte-glazes

Matte-glazes do not flow during firing and must be applied evenly.

   
How do I remove glaze from the bottom of pieces ?

To remove glaze from fired pieces

To remove glaze from the bottom of pieces that you want to dryfoot, mount a piece of sandpaper on a board or table top and simply rub off the glaze in that area.

   
What is a Crystal glaze: Glossy green and brown ?

Recipe: Glossy green and brown

Crystal glazes: Glossy green and brown
A good crystal glaze based on zinc and lithium. Spray the glaze thinner near the bottom of the pot, or it will run a lot. 1260oC with 1/2-3/4 hour at the top temperature. Does not need a slow cooling. Brown, sometimes two-colored crystals.
potash feldspar NR 28,50
quarts (flint) 33,30
dolomite 3,52
zinc oxide 19,50
barium carbonate 4,61
china clay 3,00
lithium carbonate 7,59
rutile 1,36
red ferric oxide 1,63
manganese carbonate 1,36
copper oxide 0,81

   
How do I apply glaze?

Using slips/oxide washes with glazes

Thin slips and oxide washes can be used to decorate a piece by applying them directly to the bisque or on top of a glaze. Clear, celedon, and some light opaque glazes can be used over the colorants. Be careful not to get oxides and slips on too thick--the application should be more like water colors than house paint. The colorants are mostly quite strong, and if they are
thick the overlying glaze is likely to crawl. Decorations can be brushed, stamped with foam stamps or sponges, spattered, sponged into textures, silk screened...

   
How do I apply Woodtone glazes ?

Consistency

Woodtone glazes are supposed to be thick in the jar and should not be thinned with water.

   
Why do I get greyed red or orange family glazes ?

Greyed red family glazes

Greyed red family glazes can be caused by not applying enough colour, most manufacturers recommend 3-5 coats.

   
Why is there a cloudy appearance with clear glaze ?

cloudy appearance with clear glaze

If a piece that you have coated with clear glaze comes out of the kiln with a cloudy appearance, you may be applying your glaze too heavily or not firing hot enough. Most times you can rectify this fault by firing the piece again to a cone higher.

   
Why do I get black spots in my glaze?

Black spots in glaze

If after firing, you discover some black specks in your glaze, it may be caused by the use of a dirty brush, greenware, bisque or other tools you have used. Your kiln, if dirty can cause this as well.

   
How do I mix my glazes?

Potters Percentage

The oxide, opacifier and stain additions to the base glazes are given as percentages. It is easiest to treat the oxide percentages as an additional part. For example if the basic glaze recipe is weighed as: Alkaline frit 75g+china clay 15g+flint 10g=100g, and it also requires 1% copper oxide and 2% red iron oxide, the oxides would read as 1g copper oxide and 2g red iron oxide. This method is called a “Potters Percentage”.

   
How do I stop my pieces sticking to the shelves?

Waxing: application

Wherever we apply the wax, the glaze won't stick to the bisque, so be careful not to spill it or let it drizzle down the side of your pot. Clean up any drops of wet wax with a damp sponge, and allow the wax to dry for 1/2 hour or so for best results. Rinse brushes in hot water immediately to keep them from becoming caked with wax.

   
How do I apply Lustres?

Too light an application

Areas of purple, blue or brown metallic coatings are caused by too light an application of the metallic overglaze.

   
How do I test my glazes?

Mixing glaze tests: amount

Most people mix 100g batches of test glazes, although some that use bowls or larger pieces go up to 300g. Often people make a larger batch, then break it down to smaller pieces for the addition of different colorants (stains and oxides).

   
How do I prepare a glaze?

Mix and strain you glazes

Always mix & strain your glazes before using them.
Anyone who has tested this method can tell you how important it is and how much of a difference it makes.
Mixing and straining glazes is something most beginner to intermediate potters don't do. When you start doing it, it will make a huge difference.

   
How do I test my glazes?

Why do glaze tests

There are many benefits to having test tiles for glazes. It allows you to test combinations of glazes easily and inexpensively, and serves as a permanent reminder of what a glaze looked like on a certain clay. Otherwise, you may forget very quickly.

   
What is Shino ?

Shino #2

Shino #2
Cone 10
Reduction
Nephelene Syenite 44.12
Spodumene 30.47
Kaolin 25.41
Gum Arabicum Pinch

   
What is a glaze?

Clear Gloss 2

Clear Gloss: Cone 6 Oxidation
Gerstly Borate 49.5
Silica 32.0
Kaolin 16.0
Whiting 1.5
Bentonite 1.0

   
How do I apply crackle glazes ?

Crackle glaze: accentuating the crackle

If, after several months, you notice that you have more cracks in a piece that have not been filled with antiquing when using a crackle glaze, you can go back over the piece to accent them.

   
Did you know that art glazes separate ?

What are they?

Art glazes produce a finish within themselves during the firing process.

   
What is An opacifier ?

Matte v/s semi-matte glazes,

It's hard to tell the difference between matte and semi-matte glazes, but the semi-matte glazes have a slightly higher sheen

   
What is a glaze?

Clear Bright Gloss

Clear Bright Gloss: Cone 5 Oxidation
Gerstly Borate 51.0
Silica 31.0
Kaolin 16.0
Potash Feldspar 3.0
Bentonite 1.0

   
How do I apply glaze?

Recipe: Clear Gloss

Clear Gloss
Cone 04
Oxidation
Frit 4064 (Lead Bisilicate!) 78.0
Kaolin 13.5
Silica 4.5
Whiting 4.0

Not suitable for tableware!

   
What is the dipping method?

Safety Measures:

Safety Measures:

· wear a good dust mask when handling dry materials

· wear gloves when touching any raw materilas, dry or wet

· avoid using particularly toxic raw materials, such as white lead. Use frits instead.

· wash hands carefully after contact with materials

· wear protective clothing and wash frequently

· wear a gas mask when reducing or salt or soda firing

· wash workbenches and wet mop studio floors

· if spraying glazes, wear a mask and use a spray booth

· never eat or drink near studio or working area

   
How do I apply Lustres?

Avoiding Pinholing

If your glaze surface has pinholes or other faults it will effect the finished overglaze

   
What is opalescent glaze ?

Opalescent glaze description

An opalescent glaze has a milky, translucent, sometimes bluish sheen.

   
What are some stoneware glazes?

Turquoise silky matt

Turquoise silky matt
A very loved dark turquoise blue glaze. If too thick it will run and be very dry and not good. Works best on very fine porcelain clays. I use a French clay from Limoges. 1260-1280oC with one hour at top temperature.
potash feldspar NR 51,06
barium carbonate 21,28
china clay 8,51
wollastonite 17,02
lithium carbonate 2,13
copper oxide 1,70

   
When should I use rectangular tiles?

Storing Tests: String together

String several together (for example, all the tests that you like on a certain clay, or all the tests of a certain color range), then hang the groups on nails.
As you can see, holes are important!

   
How do I glaze my ware?

Glaze Application: Trailing

Glazes can be applied using a slip trailer or simple ladle. The definition of a trailed line will depend on the fluidity of the glaze used.

   
What is a glaze?

Dry Glazes

Dry: You can purchase commercial glazes in dry form, which are usually formulated for dipping, pouring, or spraying. In addition to a brush, you will need a bucket, some water, something to stir with, and a mask to avoid breathing the dust. The advantage of dipping is that you get a more even coating of glaze, and you can do interesting things you can't do with a brush, such as double dip to get different colours on the same piece. Spraying is usually done by more advanced people since it requires good ventilation, a gun, a compressor, a booth, etc.

   
How do I glaze my ware?

Wax Resist

The same wax we use on the bottoms of our pieces can also be used decoratively. The wax can be applied to the bisque directly or applied on top of a layer of glaze. Any glaze applied afterward won't stick to the wax. Avoid trying to be too fine with wax resist. Very thin lines and small areas don't shed the glaze as well as larger areas.

   
What is Pattern base ?

Pattern base

Pattern base is a special effect glaze that will cause glazes to separate during the firing and form varied patterns.

   
How do I avoid pinholes ?

Pinholes

Another method of taking care of those pinholes on flat surfaces after glazing is to go over the piece with a brush loaded with clear water

   
How do I decorate my ware?

Semi matt cobalt green with yellow crystals

Crystal Glaze: Semi matt cobalt green with yellow crystals.
This glaze use to be very safe. It is a green semi matt glaze with more or less bright yellow crystals. 1270oC with one hour at top temperature. Not too thick.
nepheline syenite 66,05
zinc oxide 4,82
dolomite 4,51
whiting 4,82
ball clay 4,51
quarts 6,91
rutile 8,41
copper oxide 0,30
cobalt oxide 2,00
red ferric oxide 0,60

   
What are some stoneware glazes?

Recipe: Semi glossy blue and yellow

Crystal glazes: Semi glossy blue and yellow
A very popular crystal glaze with zinc. You must not apply it too thick, or it will be yellow gray and not so good. 1260-1280oC with one hour at the top temperature. Does not need a slow cooling. You can also try other combinations of coloring oxides. Very small bright crystals.
potash feldspar NR 63,49
dolomite 15,87
zinc oxide 17,46
rutile 3,17
cobalt carbonate 1,59

   
What are some stoneware glazes?

Recipe: Dark and light yellow crystals

Crystal glazes: Dark and light yellow crystals
A semi glossy crystal glaze based on frits and zinc. It tends to run not too much, if not sprayed too thick. 1260oC with ¾ hour at top temperature. Usually it behaves very good. The crystals can be large. boric frit MOK1 17,60
zinc barium frit 90420 26,40
quarts 22,20
zinc oxide 22,00
china clay 4,50
bentonite 3,30
rutile 4,00
ferric oxide 0,80

   
What is Albany slip?

Alberta slip.

What is Alberta slip.

Alberta slip is a direct substitute for Albany slip compounded by the Archie Bray Foundation to duplicate the chemical and physical properties of Albany slip.

   
How do I decorate my ware?

Liquid Glazes: commercial

Commercial Liquid Glazes: You can purchase commercial glazes and underglazes in liquid form, which are usually formulated for brushing. All you need to apply the glaze is a brush. Some glazes are difficult to brush on smoothly, you will see brush marks. Others will melt enough to erase the brush marks.

   
How do I make test tiles?

Types of test tiles: Rectangular

Rectangular test tiles with a bend (L shaped) so you can see the glaze on a vertical and a horizontal surface. Good glaze flow and coverage results!

   
How do I add texture?

Test tile attributes

Texture: It is generally a good idea to add texture to part of your test piece so you can see how the glaze will respond to texture and carvings.
Holes: Put a hole somewhere to hang your tiles on a wall board or to hang off the handle of the bucket.
Marking: Put some type of word or code that reminds what glaze this was, what clay it was on, and perhaps even firing temperature. Or simply number them and keep the details in a notebook by number.(One way to number is with one of those adjustable rubber stamps, the ones with wheels to change the number).
Dipping: Usually best to do three dips. First dip covers the whole area. Second dip covers 2/3 of the area. Third dip covers half the previous dip. So you have 1/3 with 1 coat, 1/3 with 2 coats, and 1/3 with 3 coats. (Keep the thickest coat the furthest from the kiln shelf in case it runs)
Layer multiple glazes:
For example, take a circle, dip 1/3 in glaze 1, dip 1/3 in glaze 2 (overlapping glaze 1), dip 1/3 in glaze 3 (overlapping glaze 2 on one side and glaze 1 on the other). So you get 3 solid colors, plus 3 overlap colors. Another example: take a square, dip ½ in glaze 1, turn, dip ½ in glaze 2. At this point you have two solids, plus 1 solid over the other. For the 4th section you could try layering the opposite way (glaze 1 over glaze 2 instead of glaze 2 over glaze 1), have an underglaze coat, or introduce a texture or a third color.
Other layering effects: For example, undercoat a section with underglaze, or paint an iron oxide and a cobalt oxide line so you can see if the oxide runs or stays put during firing.

   
How do I store my Materials?

Labelling Glazes

Label glaze containers with the contents, firing temperature, and any risks the materials might present to the user, always use lidded containers and store glazes away from children.

   
What is Celadon?

Celadon

Edouard's Celadon Vert
Cone 9
Custer spar 43.5%
Silica 28.1%
E.P.kaolin 10.3%
Whiting 18.1%
Bentonite 1%
Red iron oxide 1.7%

Thank you to Edouard Bastarache
for supplying glaze recipie.

   
How do I glaze my ware?

Remove dust

We can apply glaze to our work by dipping, pouring, spraying, or brushing. First, we have to prepare the bisque by lightly sponging it to remove any dust. Be careful not to get the piece wet--squeeze the sponge as dry as possible. Remember, dirty or saturated bisque can cause crawling.

   
What is Shivering ?

Shivering Description

The opposite of crazing is shivering. If the body contracts more than the glaze, the glaze can begin to chip or peel off--usually on the rim of a piece. Shivering is fairly rare.

   
What are some stoneware glazes?

Recipe: Light blue chün

Light blue chün
Works best on colored clays, but is also good at white stoneware. Apply rather thick. Good to heavy reduction. Cracks on some clays but not on others.

borax frit, MOK G-3 2,00
china clay 2,00
whiting 19,80
quartz (flint) 29,70
potash feldspar NR 39,60
talc 5,90
red ferric oxide 1,00

   
How do I glaze my ware?

Glaze Application: Pouring

The glaze is poured into vessels and onto ware. It is useful for work that is too large to dip and can provide interesting effects when different glazes are poured over a base glaze.

   
how do I get the best results in glazing?

Glaze too thick or thin

Glaze too thick: Add more water
Glaze too thin: Allow glaze to settle and then decant excess water from the top.

   
how do I accommodate glaze run?

Running

Remember that glazes run when fired so you will want to leave your coats of colour approximately 1/16-1/8” up from the bottom of the piece.

   
What are some stoneware glazes?

Black with brown or blue dots.

Black with brown or blue dots.

Apply rather thick. Works well in oxidation an then gives a semi transparent to opaque glaze with a lot of blue. In reduction it gives a more opaque glaze. You can use it on white porcelain to dark brown stoneware clays. On brown clays it must be very thick to give blue patches.

potash feldspar NR 38,57
whiting 5,71
barium carbonate 8,57
talc 2,86
ball clay 302 8,57
quartz 22,87
ilmenite 7,14
zinc oxide 5,71

   
How do I record my glaze results?

Types of test tiles: Thrown Ring

Throw a ring about 10" diameter but clay is only 2" from the perameter and the inward leaning wall about 2" high too. Then when it is leather hard cut it into maybe 8 pieces like a pizza that way you'll have stand up tiles that will behave as the walls of your pots behave.

   
What is a Satin Matt glaze recipe?

Pale /bright Matt Blue

Pale to Bright Matt Blue
Cone 9 - 10
Oxidation or Reduction
Soda Feldspar 51.0
Kaolin 30.0
Calcite 21.0
Silica 200 mesh 8.0
Cobalt Carbonate 0.5-4

   
What are some stoneware glazes?

Satin Matt Glaze

Satin Matt Glaze
Cone 9-10
Oxidation or Reduction
Potash Feldspar 45.4
Dolomite 17.6
Kaolin 22.2
Bone Ash 2.75
Silica 2.75
Talc 9.3

   
How do I fire red glazes?

Greyed red glazes

Another cause of greyed red glazes occurs during the firing. They can turn grey if fired with glazes in the yellow, black or green family, or with greenware.

   
how do I apply glazes?

Different applications

For an interesting look with a sprayer: drip latex resist on a piece and let it run down the sides. Spray glaze the piece and fire. When the wax burns away there will be a pattern where the wax ran.

   
What is Crazing?

Crazing Remedy

Crazing
One of the most common glaze defects is crazing, although in some cases crazing is a sought after effect. Crazing will occur when the glaze doesn't fit the clay body. The glaze shrinks more than the clay during the cooling, thus causing the effect. Crazing can occur after a piece has been fired. Often one will hear a bowl or platter making a so-called pinging noise long after firing. Crazing can also occur over centuries, as can be seen in many older wares, that would have looked okay initially.
Remedies:

· Add silica to the clay body

· Add silica to the glaze

· Add alumina to the glaze

· Soak the kiln

   
How do I apply Lustres?

multiple applications

The use of metallic overglazes and lustres add a great deal of beauty and value to a piece. It should be noted that a piece is even more beautiful with multiple applications with firings in –between.

   
a green glaze that won’t take a gold firing?

a green glaze that won't take a gold firing?

Do you have a green glaze that won't take a gold firing? Try firing it at a higher or lower temperature than your usual gold fire (cones 018-022)

   
How do I apply crackle glazes ?

Crackle glazes: even application

Crackle glazes may have a tendency to drag when applied, but can be smoothed out with a coating of water on your brush after applying.

   
How do I do certain areas that you do not want to glaze?

Glaze on glaze

If there are certain areas that you do not want to glaze or you do not want colours to overlap, you may have difficulty if not applied properly. Many leave 1/8” –3/8” between colours if they do not want them to run together.

   
What is Delayed crazing

Delayed crazing

Delayed crazing refers to the period of time that a crackle glaze continues to crack. This effect can last for months

   
What are some stoneware glazes?

Tenmoku

Tenmoku glazes and similar:
Good black Tenmoku with brown edges on white or light gray clay. Not too thick. 1260-1280oC in normal reduction. Semi glossy. More rost-colored with yellow or brown bodies.

Cornish stone 64,57
china clay 9,71
quartz 12,91
whiting 16,12
red ferric oxide 8,06

   
What are Ashes in ceramics?

Ashes in ceramics

What are Ashes in ceramics?

Ashes are the noncombustible remains of animal (bone) and vegetable matter used by the potter as a source of body and glaze fluxes. The commonest uses are of bone ash in bone china body and vegetable and wood ashes in stoneware ash glazes.
The ashes provide fluxing and other oxides. The main oxides involved are those of calcium, phosphorus, potassium, sodium and aluminium with silica and many trace oxides. Although the original matter is organic (that is, with carbon being the most important element and hydrogen,
Nitrogen and sulfur also involved) the potter is seeking the inorganic content. Thus from a large bulk of wood the potter collects a relatively small amount of ash.

The ash needs to be washed well to remove all unwanted compounds and firing takes care of the rest.

   
What is a glaze?

Copper Lustre

Comments: Here are a couple of tried and true glazes for raku. Not sure at what temperature they mature; I just pull 'em out when the surface looks melted. Not suitable for tableware! Bisque fire work to 1100o C. Mix glaze same day as firing. Apply glaze thickly
Dribble glaze on thickly for effects. *see disclaimer*
Copper Lustre
Raku Reduction
Gerstley Borate 80
Cornwall Stone 20
add Copper Carb 3
Red Iron Oxide 1

   
What is a glaze?

Clear Gloss

Clear Gloss: Cone 5 - 6 Oxidation
Nephelene Syenite 40.0
Ferro Frit 4508 45.0
Kaolin 10.0
Silica 10.0

   
What are glazes?

General guidelines

Glazes are easy to use and produce excellent results if applied and fired properly. Read all recipes and lables carefully. Keep working areas clean of dust.

   
What are some Earthenware Glazes?

Middle red with darker spots

Middle red with darker spots: It can be a very pleasant semi glossy red glaze with strikingly darker spots. But not always! 1260oC with half an hour of oxidation at top temperature. Not too thick or it will be a dull redbrown.
potash feldspar NR 35,40
petalite 5,20
quartz (flint) 26,40
china clay 1,70
borax frit MOK-G3 17,10
whiting 13,10
tin oxide 1,10
copper carbonate 0,53

   
What are some Copper red glazes?

Rose-colored, crackled semi matt

Rose-colored, crackled semi matt

It is a pleasant semi matt rose glaze with a good crackle pattern. 1270oC with half an hour of oxidation at top temperature. Not too thick or thin. Works sometimes well on top of a Peachbloom in a second firing. Then it can give very sharp dark red spots.

nepheline syenite 36,70
barium carbonate 6,40
quartz (flint) 27,50
zinc oxide 3,70
whiting 22,1
Rose-colored, crackled semi matt 0

   
How do I make test tiles?

Types of test tiles: Thrown hollow cylinder

Throw a wide cylinder without a bottom about two or three inches tall and put two or three grooves in it. When it's leather hard, cut it like a pie, in four, eight etc pieces depending on how wide I want it to be and to make identical tiles. Each "slice" stands by itself and can be easily dipped in different ways at different angles to show different thickness of the glaze.

   
What are some stoneware glazes?

Shino

Edouard's Shino
Cone 9
Nepheline/Syenite 75.95%
Lithium carbonate 3.03%
Whiting 0.70%
Ball clay 17.53%
Silica 2.79%
Bentonite 1%

Thank you to Edouard Bastarache
for supplying glaze recipie.

   
What is a crackle glaze?

Clear Crackle #2

Clear Crackle #2
Cone 8-10
Oxidation or Reduction
Potash Feldspar 40.0
Silica 20.0
Calcite 16.0
Eckalite 12.0

   
How do I glaze my ware?

Slips and stains

Don't forget the possibilities available with raw clay. Unglazed surfaces can be brushed with slip or stains, and colorants can be used to highlight stress cracks or textured surfaces. Clay coloring is responsive to variations in kiln atmosphere, so expect the unexpected. Unglazed clay can show the same kinds of blushes and flashes as our glazes often do, and coarse or textured surfaces are sometimes best just left alone.

   
how do I achieve the desired glazing results?

Maturity

All glazes need to be fired to maturity to achieve the desired results. The temperature for maturation varies with the glaze formulation.

   
how do I highlight The beauty of a crackle glaze ?

Crackle glaze

The beauty of a crackle glaze is to create that old look with the cracks. After the piece has set for a few days, coat the entire piece with a dark translucent stain and let dry. Then wipe off with a mineral spirit soaked rag. Only the cracks will hold the colour, accenting your piece and making it look antique, this can also be accomplished with ink.

   
can I use an air-brush on ceramics?

Air-brush

It is possible to use glazes in an air-brush but they must be watery thin and strained well. Good coverage will require a number of coats. Be sure to apply evenly to avoid runs.

   
Why do I get greyed red or orange family glazes ?

Greyed red or orange family glazes

You can get greyed red or orange family glazes by firing your pieces too hot. Temperature should be at a 06-07 for earthenware.

   
Why am I having trouble with red glazes?

Trouble with red glazes

If you have trouble with red glazes, you might find it helpful to know that this glaze may not act normally if fired with certain other glazes or greenware. Ask your supplier.

   
What are Mid Fire Glazes?

Rose-colored, crackled semi matt

Rose-colored, crackled semi matt

It is a pleasant semi matt rose glaze with a good crackle pattern. 1270oC with half an hour of oxidation at top temperature. Not too thick or thin. Works sometimes well on top of a Peachbloom in a second firing. Then it can give very sharp dark red spots.

nepheline syenite 36,70
barium carbonate 6,40
quartz (flint) 27,50
zinc oxide 3,70
whiting 22,10

   
What are some stoneware glazes?

Blue Speckle

Blue Speckle
Cone 10
Oxidation or Reduction
Potash Feldspar 55
Whiting 15
Ball Clay 5
Silica 200# 25
Red Iron Oxide 4
Rutile Flour 3

   
How do I thin glaze?

Thinning glaze

Glaze that has thickened can be thinned to the proper consistency with the addition of water.

   
What are some stoneware glazes?

Recipe: Glossy gray, blue and brown

Crystal glazes: Glossy gray, blue and brown
A glaze based on zinc and lithium. Spray the glaze thinner near the bottom of the pot, or it will run a lot. 1260oC with 1/2-3/4 hour at the top temperature. Does not need a slow cooling
potash feldspar NR 29,00
quarts (flint) 34,50
dolomite 3,60
zinc oxide 18,50
barium carbonate 4,14
china clay 3,31
lithium carbonate 6,90
rutile 1,38
red ferric oxide 1,24
manganese carbonate 2,21
cobalt carbonate 0,22

   
What are some stoneware glazes?

Transparent

Edouard's Transparent
Cone 9
Custer spar 43.5%
Silica 28.1%
E.P.kaolin 10.3%
Whiting 18.1%
Bentonite 1%

Thank you to Edouard Bastarache
for supplying glaze recipie.

   
What is Crawling?

Crawling Remedy

Crawling
The glaze pulls together and forms separate droplets on the surface of the clay body. Crawling occurs when the glaze contracts too much during the heating cycle and doesn't get sufficient a chance to smooth over. Another cause may be due to bad adhesion of the glaze, e.g. when glaze was applied to a very dusty pot.
Remedies:

· Substitute some of the clay content of the glaze with kaolin

· Substitute glaze fluxes such as zinc oxide and dolomite with their calcined form

· Clean off any dust with a sponge prior to glazing

   
Can I thin lustres?

Thinning lustres

Halo lustres and metallics can never be thinned since the solvents in these products must be present in exact proportions. Every effort must be made to insure little evaporation.

   
How do I make your own test tile chart?

Test tiles DIY

You can make your own test tile chart just like your local studio by using small inexpensive molds and pouring your own tiles.
Or
Roll a slab and cut 2"x4" rectangles. Mark the rectangles with grooves, this gives you a guide to the glaze run. Cut a small hole in the corner, to make hanging easy.
Bisque.

   
Why do I have a lot of streaks or running of glaze ?

a lot of streaks or running of glaze

If, when you remove a piece of ware from the kiln, it has a lot of streaks or running of glaze to the point where it is dripping off the bottom of the piece, you have applied too much glaze.

   
How do I use Texture type glazes in combination ?

Texture glazes in combination

Texture type glazes may be used in combination with other type glazes. It is possible to create a raised design over a satin glaze since it moves very little in firing.

   
What is the dipping method?

Dipping method

If you have a lot of pieces that you want to glaze, you can try the dipping method. There a re special glazes designed for this which are concentrated to cover in one coat.

   
What are some stoneware glazes?

Recipe:Glossy cobalt blue

Crystal glazes: Glossy cobalt blue
One of my most popular crystal glazes based on zinc and lithium. Too thick it will run a lot, and it is not so easy to find the best thickness. Always spray the glaze thinner near the bottom of the pot. 1260oC with 1/2 to one hour at the top temperature. Does not need a slow cooling, but will sometimes be better if you make a second equal firing. A delicate but difficult glaze.
potash feldspar NR 28,40
quarts (flint) 33,00
dolomite 3,66
zinc oxide 19,26
barium carbonate 4,58
china clay 2,75
lithium carbonate 7,34
rutile 0,92
cobalt oxide 1,38
red ferric oxide 2,02
manganese carbonate 0,37.

   
How do I make Egyptian Paste?

Albany slip.

What is Albany slip.
Albany slip is a slip glaze made from Albany clay alone or modified with feldspar and other fluxes. The clay is an alluvial deposit of the Hudson River in the vicinity of Albany in New York State.
When Albany clay is used as a glaze it produces a series of rich yellows, blacks and browns over a wide range of temperatures from 1100c to 1300c. It was first developed when the early American potters followed the European practice of refining the body clay to make a glaze.
In Britain, the mud from many of the larger tidal rivers gives similar effects. It can b modified with feldspar, wood ash etc. and gives mostly tenmoku-type slip-glazes for stoneware.

   
What is a glaze?

Why Glaze?

Why should we glaze our pots? Historically, most pottery was glazed to increase its function. Glazing provides a hard, water tight, scratch resistant, and sanitary surface. In addition, a properly formulated glaze also strengthens a piece of ware. Glazing gives us more control over the aesthetics of our pieces. We can decide color, surface, and any decorative elements we want to add to our work. Finally, keep in mind that we don't have to glaze our pots. Raw clay can be quite beautiful, and it can be decorated in many ways that don't require glaze.

   
How do I apply Lustres?

Sealing Metallic colours

A coating of clear spray will help seal metallic colours and make them easier to antique

   
How do I get a deeper colour of overglaze?

Wise use of your metallics and lustres.

Never dip your brush diretly into a container of metallic or lustre to begin application. Always pour a small amount of colour into an alcohol cleaned container and load brushes from this. These materials are expensive and you may have a contaminated brush and ruin an entire supply rather than just a bit in a dish.

   
How do I fire lead free glazes?

Leadfree glaze problems

Lead softens a glaze and allows it to be fired over several cone numbers. Glazes made without lead have a narrower firing range. Typically, lead glazes are able to be fired over a four cone number range (example 08 to 05). Lead free glazes typically need to be fired within two cone numbers (example 06 to 05) - less than half of that for lead glazes.

   
What is Stoneware?

Tried and True

Following is a brief description and review of different stoneware glazes: Celedons- for example Hot Tea with Iron, or Celedon Leach Korean are well know recipes. Celedons are stoneware glazes that contain iron which produce green, gray and gray-blue colors in a reduction firing. Usually with many visible small cracks. Copper reds- for example Coleman's Copper #2, or Oxblood are well known recipes. Copper reds are stoneware glazes that go from white to bright red in a reduction firing. Shinos- for example shino can vary from white to orange in color. Shinos are stoneware glazes which when applied thin will be white and when applied thicker will be orange. Temmekous- for example temmekou is a stoneware glaze which can vary from a beautiful black to a rich brown.

   
What is a crackle glaze?

Clear Crackle

Clear Crackle
Cone 9-10
Oxidation or Reduction
Soda Feldspar 80.0
Whiting 10.0
Kaolin 10.0

   
How do I fire overglazes/lustres?

Overfired lustres

Cracked metal overglazes are caused by firing to an excessive temperature
If a piece removed from the kiln that has had gold applied has hair-line cracks, it has been over-fired.

   
How do I decorate my ceramics

Spraying

Spraying may sound easy but is not necessarily. Spraying the interior of a vase for example would be difficult, as the spray has little room to maneuver in the small space and is ejected again quickly, possibly spraying into your face. To remedy this, such vessels are first poured and the exterior sprayed afterwards. The advantage to spraying is that glaze cover is very even. This can be crucial with some glazes. Hint: to check the thickness of the sprayed glaze, scratch the surface with a pin. If it is of sufficient thickness, the scratch can be smoothed over by rubbing.

   
How do I apply glaze?

Recipe:Clear Gloss

Clear Gloss
Cone 08 - 04
Oxidation
Ferro Frit 4110
Whiting
Kaolin 85.0
5.0
10.0
Clear Gloss
Cone 04
Oxidation
Ferro Frit 3124 85.0
Ball Clay 15.0

   
How do I glaze my ware?

Mixing the glaze

Before we can use the glaze, we have to mix it. The liquid glaze tends to settle. If there is a noticeable layer of water on the surface of the glaze, it's best to use the electric mixer. Be careful with the mixer around long hair and loose clothes, and always make sure it's clean before sticking into the glaze. If the glaze is just lightly settled, it can be stirred with a stick. Many glazes will settle quickly as we work with them, so keep the stick handy.

   
How do I apply Lustres?

Blistering or flaking of a lustre

Blistering or flaking of a lustre is caused by too heavy an application.

   
How many coats do I apply?

Brush on: check labels

Most manufacturers recommend that you apply glazes with three coats. There are some one and two coat glazes so be sure to check labels.

   
What is a glaze?

Black Gloss #2

Black Gloss #2
Cone 10
Oxidation or Reduction
Potash Feldspar 43
Whiting 17
Ball Clay 13
Silica 200# 27
Red Iron Oxide 10
Cobalt Oxide 1

   
What glaze should I use?

Ash Glaze

Ash Glaze
Cone 10-11
Wood fired reduction
Ash 40
Potash Feldspar 20
Ball Clay 40

   
How do I apply glaze?

Clear Gloss 4

Clear Gloss: Cone 6 Oxidation
Volcanic Ash 63.7
Ferro Frit 3134 27.3
Koalin 9.0
Bentonite 1.0

   
How do I apply Lustres?

multi-coloured effect in your mother-of-pearl lustre

If you want a multi-coloured effect in your mother-of-pearl lustre, it can be accomplished by firing your lustred piece with different coloured glazed pieces at the same time

   
How do I apply glaze?

Transparent glazes Description

As the name implies, transparent glazes will allow colour to show through, but in the process diffuses them.

   
How do I apply brush-on glazes?

Coverage

Whatever the number of coats, glazes should be applied to your ware in a flowing manner, being sure that you cover your pieces well and evenly.

   
How do I decipher The size of crystals ?

The size of crystals

The size of crystals in a crystal glaze will determine the amount of colour variation. The larger the crystals, the more variation in colour.

   
What is a Silky matt greenish off white crackle glaze recipe?

Silky matt greenish off white crackle glaze

Silky matt greenish off white crackle glaze
A very pleasant smooth glaze with a fine dark crackle pattern. Sometimes very beautiful orange spots. If too thick it will be glossy and not nice at all. Works best on porcelain.

nepheline syenite 55,00
dolomite 23,00
china clay 21,00
quarts 1,25
copper carbonate 0,75

   
How do I mix my glazes?

Mixing glaze tests: Finding 1gm accurately

If your recipe calls for .5g and your scale is only accurate to 1g, weight out 2-4 grams onto a piece of paper. With a blade, smooth it into a flattened square, and separate it in half by eye. Or into quarters.

   
What is a glaze?

Dry Alligator

Dry Alligator: Raku Reduction. Not suitable for tableware! Bisque fire work to 1100o C. Mix glaze same day as firing. Apply glaze thickly Dribble glaze on thickly for effects. *see disclaimer*
Gerstley Borate 52.5
Nephelene Syenite 12
Bone Ash 23.5
Copper Carb 12

   
What is a glaze?

Royal Blue

Royal Blue
Cone 10
Oxidation or Reduction
Nephelene Syenite 30
Whiting 15
Talc 5
Zinc Oxide 5
Ball Clay 10
Silica 200# 35
Cobalt Oxide 1

   
What are some stoneware glazes?

Plain White Gloss

Plain White Gloss
Cone 10
Oxidation or Reduction
Potash Feldspar 29
Soda Feldspar 15
Whiting 9
Silica 200# 19
Talc 12
Kaolin 9
Tin Oxide 7

   
How do I apply glaze?

Clear Matt

Clear Matt
Cone 9
Oxidation or Reduction
Talc 30.0
Whiting 25.0
Potash Feldspar 34.0
Silica 11.0
Rutile 2.0

   
How do I create a woodtone effect?

Application tips

Woodtone glazes must be applied evenly but not too heavily. Each coat should be smoothed with fingers to avoid bubbling.
As you apply each coat of woodtone glaze, it must be thoroughly brushed out into a thin layer.
When applying woodtone glazes, the pressure you apply on each brushstroke makes the small dark specks in the glaze dissolve and become dark streaks, which in turn become wood grain when fired.
When applying wooodtones, be sure that all brush strokes are in the same direction.
On highly detailed pieces you may need to thin woodtone glazes slightly to get the specks to form the wood grain effect in the crevices.
Don't worry about over-brushing woodtone glazes. The brushing will help to streak and form the wood grain better.

   
What are Art glazes ?

Applying Art glazes

Because runs are the basis of art glazes, application of the first coat should cover the entire piece. Succceeding applications should be only ¼” from the bottom of the piece.

   
How do I apply glaze?

application of transparent glazes

The best method of application of transparent glazes is to thin glaze with water so it is just slightly thicker than water itself and apply recommended number of coats.

   
What is An opacifier ?

An opacifier

An opacifier is a material that causes a transparent glaze to become opaque.

   
How do I fire my ware?

Heat variation

Most kilns vary in temperature from top to bottom. To determine how much your kiln varies, place witness cones on each shelf when making firings. Usually, there is less difference top to bottom for hotter firings.

Each kiln has its own personality and the solution for improving temperature uniformity may vary.

   
What are some stoneware glazes?

Ash glaze

Benji's ash glaze
Cone 9
Hardwood ash(washed) 16.5%
Softwood ash(washed) 16.5%
Custer spar 39%
E.P.kaolin 13%
Whiting 6%
Barium carbonate 5%
Silica 4%
Black iron oxide 1%
Bentonite 2%

Thank you to Edouard Bastarache
for supplying glaze recipie.

   
What are some stoneware glazes?

Dry Turqoise

Dry Turqoise
Cone 8
Oxidation
Nephelene Syenite 50.0
Barium Carbonate (Toxic!) 30.0
Litium Carbonate (Toxic!) 3.0
Ball Clay 8.0
Flint 9.0
Copper Carbonate 2.0

Comment: Fire in oxidation. Not suitable for tableware!

   
What is pinholing?

Pin-holing Description

Pin-holing is most common to matt glazes. Air escaping from the bisqueware will often form little holes in the surface of the unfired glaze as we glaze a pot. For gloss glazes these will usually smooth out in the firing, but for matt glazes they often remain. It's a good idea use your finger to rub out these little holes before submitting your pieces to be fired.

   
What are some stoneware glazes?

Clear Gloss

Clear Gloss
Cone 9
Oxidation or Reduction
Potash Feldspar 44
Whiting 18
Kaolin 10
Silica 28

   
What happens if I over-apply transparent glazes?

Transparent glaze Over-application

It is important that you do not over-apply transparent glazes since too much colour will give a milky finish over colours

   
How do you know your own glaze tendency ?

Know your brush tendency

After you have used glazes a few times, you will discover if you fall in the light or heavy glaze category. Everyone loads their brush differently and you should know your own tendency so you can gauge how much glaze to apply.

   
What are Antique glazes ?

Effects

Antique glazes give your pieces a frosted type finish with a variation of two to three shades of the same colour. This effect is good for all types of pieces.

   
What are Mid Fire Glazes?

Blue semi matt to glossy

Blue semi matt to glossy
Matt and best if fairly thin, glossy if too thick. 1260-1280oC in normal reduction
potash feldspar NR 39,60
china clay 18,80
quartz 14,60
whiting 22,90
titanium oxide 4,20
cobalt carbonate 1,60

   
How do I decorate my ware?

Dry Glazing description

Dry glazing: In the context of single firing, dry glazing is the practice of applying glaze to dry, unfired ware.

   
What is a glaze?

Mossy Green

Mossy Green
Cone 03
Oxidation
Potash Feldspar 33
Whiting 34
Kaolin 30
Cobalt Carbonate 1.3
Red Iron Oxide 4.0
*See Disclaimer*

   
What are other ways to apply gold?

Gold pens

You can apply gold using a pen designed for that purpose.

   
How can I monitor glaze flow?

Glaze flow

Some glazes do flow more than others during firing, but it is impossible as a beginner to know which ones do and don't. You will have to rely on the knowledge of your teacher. Though a common rule of thumb is: the thicker and more varied the application the greater the tendency to run.

   
How do I make a test tile?

Types of test tiles: Extruded hollow form

Extrude a hollow form with a hexagonal die, use a serrated rib to texture one side. When leather hard, cut into logs. You have a piece that stands and gives you plain and textured test reading of the glaze.

   
How do I spray my glazes?

Spraying Glazes: Booths

Separate equipment is required for spraying, which is not always available in the studio pottery: a glaze spray gun, a compressor, a mask and a glaze booth. The glaze booth extracts fine glaze mist, which should not be inhaled from the air. This is done with an extractor fan. More sophisticated spray booths have a wall of running water to trap most of the glaze, so it is not just ejected into the atmosphere (important where toxic ingredients are used!).

   
What is Shivering?

leadfree glaze shivering

If shivering occurs, fire one cone cooler. You may need to select another body for your bisque. Firing too cool is not a good idea since the strength is reduced and porosity increased, both of which may cause problems during use of the final piece.
Is Your Kiln Uniform in Temperature?
If temperature in your kiln varies by more than 1 to 2 cones, then glazed ware in one part of your kiln may fire okay, while ware fired in another part of your kiln will have a problem.

   
What should I keep in mind when designing my studio?

Layout

Workshops The layout and design of your work area will depend on many factors and no two potters will come up with the same solution. The first consideration will be the amount of space available, how many people are going to work there, and whether the space already exists or is to be built from scratch. If you are using an existing building, some of the design decisions have already been made for you, but the following Article should be of some help: Studio/Workshop design - Layout

   
What is a glaze?

A Disclaimer

Disclaimer: It is the responsibility of anybody using the above glaze recipies to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips.com nor its Guru, Jan, will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
What is the recommended firing temperature.

Recommended firing temperature.

Although most glazes are fired in the 05-06 cone range always check the label for the recommended firing temperature.

   
What is pinholing?

Crawling Description

Crawling is the flaw we're most likely to see as a result of misapplication of the glaze. A crawled glaze coating will peel off the clay or an underlying glaze layer leaving a bald patch. If the raw glaze hasn't adhered well to the bisqueware, the surface tension of the glaze can make it peel away from the surface either as it dries or fires. If the bisque is dusty or saturated with water, the glaze won't stick very well. Glazes that contain lots of clay, zinc or gerstley borate are predisposed to crawling because these materials tend to hold a lot of water and shrink a lot as they dry. If the glaze is applied too thickly it only makes matters worse.

   
What are some stoneware glazes?

Very reddish brown, semi matt with darker spots

Very reddish brown, semi matt with darker spots

Rather thick or it will be no spots. 1260-1280oC with one hour at the top temperature. One of the most red glazes I know based on ferric oxide in oxidation. You can try other simple boric frits with not too low maturing temperature instead of G-3.

feldspar NGP 37,22
bone ash 12,41
talc 8,68
petalite 12,41
quartz (flint) 9,93
ball clay 7,44
red ferric oxide 6,95
borax frit MOK G-3 4,96

   
How do I prepare a glaze?

Sieving glazes

The only correct way to glaze your work is to thoroughly mix and strain each glaze you use. The proper way to mix is either with a wisk (if the glaze is not settled and hard) or an electric mixer tool. Once the glaze is mixed, thoroughly strain it through a large sieve into a container suited to the pot you need to glaze. If you don't already do this you will be amazed at what you don't find because you do find a lot more than you'd expect. This is especially important if you work in a community lab or art center facility where many people use the glazes. This single step will improve the consistency of your glazes and help to yield beautiful pots.

   
How do I apply glaze?

Semi Opaque Tan/Cream

Semi Opaque Tan/Cream E/W
Cone 04 - 03
Oxidation
Calcium Borate Frit 8.0
Lead Bisilicate (Toxic!) 60.0
Rutile 8.0
Bentonite 4.0
Silica 4.0
Potash Feldspar 16.0
Not suitable for tableware!

   
How do I prepare my colours?

Add a marble to keep glazes mixed!

You know how you get those spray can of household items with the bead inside to help mix them when you shake the can? You can do the same thing by adding a marble to a jar of colour before you mix it and it will help you complete the job.

   
What are some Copper red glazes?

Recipe: Copper red glaze

Copper red glazes:
Glossy clear red

Always a good and safe clear red, even in the least reduced parts of the kiln. Too thick it will run. 1260oC with 1/2 hour oxidation at top temperature. Crackle on some clays.

nepheline syenite 37,80
quartz (flint) 27,60
borax frit MOK1 18,40
ochre 0,50
whiting 7,50
dolomite 7,50
tin oxide 0,75
black copper oxide 0,28

   
What are some Raku & Black Fire Glazes?

Raku glaze application

Raku glazes, like most low-fire glazes, don't need to be applied as thick as stoneware glazes; so it's usually fine just to brush them on. Try to spread an even coating, and remember not to get any glaze on the bottom of the piece. Two coats is okay unless the glaze is very thin. Copper matt glazes are often applied in a very thin coat by brushing them on like a wash or by
spraying. Raku glazes can be dipped if watered down to the right consistency, but ours are prepared for brushing.

   
How do I decorate my ceramics?

Experience the world of glazes!

When you are getting started the wide range of colors and textures can seem amazing but also overwhelming. In the beginning - try everything. What you will probably find is you quickly narrow it down to four or five of your favorites. I'll save you some time and tell you some consistent cone 10 glazes that knowledgeable potters use again and again: Shino, Temeku, Celedon, Copper Red, and Leach White.
In the beginning try many glazes as you will find specific applications.

   
How do I unblock a spray nozzle

Nozzles of spray cans

When you have trouble with the nozzles of spray cans or airbrushes, try soaking them in fingernail polish remover.

   
What is froth ?

Froth or foam effects

Froth or foam is available from manufacturers in a variety of colours or you can tint it yourself with one-strokes. It can be used to create a lava effect, snow or a variety of effects. The heavier the coat you apply, the more bubbled and foamy it will be.

   
How do I test my glazes?

Types of test tiles: Thrown "T's"

Throw wide, shallow, bottomless vertical sided bowls. Leave a "flange" on the inside and outside bottom. Tool one side when dry, then cut vertically. This gives you a bunch of upside down "T" shapes with a slight curvature. Gives good run and coverage results.

   
What is crazing?

leadfree glaze crazing

If crazing occurs and the witness cone indicates the glaze and bisque firings are properly fired, make some tests by firing the bisque progressively hotter (eg. if you fire to bisque 05, test to 04, then 03).
When you fire hotter, the expansion of the bisque is changed and glaze on the bisque may fit better.

   
What are some stoneware glazes?

Copper Red

Copper Red
Cone 10
Reduction
Potash Feldspar 43.5
Silica 27.8
Soda Ash 4.2
Whiting 12.2
Tin Oxide 0.85
Barium Carbonte (Toxic!) 8.5
Kaolin 2.1
Bentonite 0.43
Copper Carbonate 0.3
Iron Oxide 1.07

Comments: keeps two weeks. Reduce heavily from 850 C. Not suitable for tableware!

   
What is a Shino glaze recipe?

Shino #1

Shino
Cone 10
Reduction
Potash Feldspar 83
Whiting 9
Silica 8

   
What are some stoneware glazes?

Black Gloss

Black Gloss
Cone 9 - 10
Oxidation or Reduction
Potash Feldspar 46.0
Dolomite 16.0
Kaolin 19.0
Iron Oxide 3.0
Cobalt Carbonate 1.5

Comments: fire in oxidation or light reduction. Heavy reduction will result in metallic black.

   
What glaze should I use?

Satin Matt

Satin Matt
Cone 9 - 10
Oxidation or Reduction
Nephelene Syenite 37.2
Talc 11.9
Whiting 11.1
Kaolin 28.0
Silica 12.5

   
What is a reduction firing?

Copper Lustre

Copper Lustre: Raku Reduction. Not suitable for tableware!
Gerstley Borate 80
Cornwall Stone 20
add Copper Carb 3
Red Iron Oxide 1

   
What Precautions when using dry ingredients?

A Disclaimer

Disclaimer: It is the responsibility of anybody using these glaze recipes to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips nor its Ceramic Guru, Jan will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
Why do I have pinholes in my glaze?

Preventing pinholes

If you have a problem with pinholes appearing in your glaze, try sponging it on rather than using a brush.

   
How do I care for my brushes?

Mother-of-pearl lustre brushes

It is important that you always keep one brush soley for Mother-of-pearl lustre and use it for nothing else. You can use the same brush for some other overglazes as long as it is thoroughly cleaned between different colour uses.

   
How do I avoid contamination?

Lustre brush care

Brushes used for lustres and metallics should be kept thoroughly clean and protected from contamination between uses.

   
What is the best Ventilation ?

Ventilation

Ventilation is the key to satisfactory firing of metallics and lustres. The kiln should remain open until all smoke and colour have ceased.

   
What is a lead glaze?

Lead glazes

The label ”lead safe” does not necessarily mean that a glaze contains no lead, but it does meet minimum government standards for dinnerware items. A lead-free glaze means that it contains no lead at all.

   
What consistancy are Woodtone glazes ?

Finishes

Woodtone glazes produce finishes similar to wood colours and are quite thick, almost jelly-like in consistency.

   
Can Crackle glazes be used for food?

Crackle glaze: application

It is advisable not to apply a crackle glaze on a piece that has another type of glaze on it too. When fired, there will be two different expansion rates and this may cause pieces to break or crack

   
How do I use Texture type glazes in combination ?

Froth

Did you know that froth is a type of glaze that when fired will produce a foam appearance? It is commonly used to simulate snow.

   
Why do glazes coming out with a grainy surface?

glazes coming out with a grainy surface,

If you have a problem with glazes coming out with a grainy surface, you may be applying them too thin. The best way to correct this problem is to warm piece slightly and apply another coat, then re-fire to proper cone.

   
What are Crackle glazes

Crackle glazes: effects

Crackle glazes are formulated to produce those patterns of tiny cracks. To control the amount of cracking, use a thin coat of glaze for a small pattern and for a large pattern a heavy coat of glaze. Bisque must be fired to cone 06.

   
o I best apply Woodtone glazes ?

Which brush?

Woodtone glazes are best applied with a stiff bristled brush. You can use a variety of brush styles but the key is to brush glaze only in one direction, working out the streaks. Rub each dried coat of colour with fingertips to smooth out brush strokes.

   
What are some stoneware glazes?

Sorelslag

Edouard's Sorelslag
Cone 9
Custer spar 56.8%
Dolomite 13.6%
Whiting 10.6%
Zinc oxide(calc.) 3%
E.P.kaolin 16%
Magnesium carbonate 1%
Sorelslag(200 mesh) 4%

Comments: Sorelslag is a titanium dioxide slag made by QIT-Quebec Iron and Titanium, located in Tracy,Quebec.
Its general formula is as follows:
Tio2.82%
Feo8%
Sio2.2%
Al2o3.3%
Mgo5%
Thank you to Edouard Bastarache
for supplying glaze recipie.

   
What is a glaze?

Make your own

Make your own: This is the most advanced form of glazing. Using recipes, you buy raw materials and mix them. In addition to the other things, you will need recipes, which may be obtained from many books and web site. You also need the chemical, which make up your glaze, a scale, a sieve, and a temprement which allows experimentation. Sometimes your glazes won't turn out quite right. You will have to learn how to modify those glazes to solve whatever problem you're having. Other times they will be stunning.

   
What is Earthenware?

Earthenware Glazes

Earthenware Glazes (low fired - Cone 04- 06)Earthenware glazes are more straight forward and predictable than stoneware glazes, they are mainly shiny and come in only a few colors. Usually clear, white, blue, and amber are available at most art centers or community studios. The best way to apply earthenware glazes is to brush it on your pot. You can have fun applying slips to earthenware clay for designs or variations. Bright colors can be produced by applying mason stains. Flower pots are unglazed fired earthenware.

   
What is lustre?

Recipe: Red Clay Paste lustres

Red Clay Paste lustres
a.red clay 20
copper carb 20
+ vinegar

b.red clay 50
copper carb 25
silver nitrate 1
+ vinegar
NB SILVER NITRATE is very poisonous. It also stains your hands and clothes. i)Always wear rubber gloves -even when decorating. ii) dissolve silver nitrate in hot water before adding to pigment paste

   
How do I glaze?

Brush-on Glazes

Brush-on Glazes
Brush-on glazes are glazes especially formulated for brushing onto ceramic work. This makes decorating very easy. These glazes are formulated so that brush marks will largely smooth over, but at the same time the glaze won't run, if fired to the right temperature. Brushing on glazes also enable variations in decoration, that would otherwise be impossible. The difficulty is getting the combination of thickness and firing temperature right, but this is -- as with so many things -- a matter of trial and error.

   
How do I apply glaze?

Lead safe glazes.

Pieces that you plan to use for food should be glazed only with ‘lead safe' glazes.
Lead safe glazes are those that are formulated to meet federal minimum standards for the amount of lead contained in the formulas.

   
How do I fire overglazes/lustres?

When gold comes out of the kiln with purple spots

When gold comes out of the kiln with purple spots it is usually caused by too thin an application of gold or too much thinner in the overglaze.

   
What are some stoneware glazes?

Stiff White Crackle

Stiff White Crackle
Cone 8 - 9
Oxidation or Reduction
Potash Feldspar 80.0
Whiting 10.0
Silica 10.0

   
What is glaze?

Description

Glazes are a formulation of minerals, water and other chemicals.

   
How do I test my glazes?

Types of test tiles: Small cups

Small cups (pinched or thrown) with glaze on the interior. Gives great flow and coverage results. Try texturing one side, and overlap the different glazes over both texture and smooth parts of the form.

   
How do I refire a glazed piece ?

Reglazing a piece:description

First, note that this process is never predictable. In most cases you can make a new piece in less time than you can spend re-glazing it, with much more predictable results. But sometimes there is that piece you can't part with and really want to re-glaze. Here are some things you can try to increase your success rate. The goal, of course, is to get the new glaze to stick to the old glaze.

   
How do I apply glaze?

Recipe: Brilliant Ink Blue

Brilliant Ink Blue
Cone 4
Oxidation
Ferro Frit 3134 50.0
Potash Feldspar 20.0
Ball Clay 20.0
Zinc Oxide (dense) 10.0
Cobalt Carbonate 3.0
Comment: possible to fire in reduction

   
What is flux?

Flux composition

A ‘flux' is composed of lead, lime or other materials that are combined with ceramic clays to reduce the speed and maturing temperature during firing.

   
Can Crackle glazes be used for food?

Crackle glaze: total coverage

Do not use crackle glaze on the outside of a piece if another type of glaze is being used inside.

   
What is crazing?

Crazing Brief Description

The effect of cracks that appear in glaze that are unwanted are called crazing and may be caused from an under-fired clay body. Bisque should be fired one to two cones higher than your glaze firing except for those glazes calling for a special firing.

   
What are some stoneware glazes?

Recipe: Black and blue with silvery spots

Crystal glazes: Black and blue with silvery spots
This glaze can be a little tricky, but when everything is OK it is very good. You must try out the right thickness, and know that it will run if too thick. It is opaque or half transparent, glossy or matt with silvery or (blue) black crystals. Make a lot of tests before you give it up! 1270oC with ½ hour at top temperature.
nepheline syenite 69,25
zinc oxide 5,77
wollastonite 11,51
magnesium carbonate 3,85
Albany slip (the real thing) 7,70
rutile 1,92
copper oxide 3,08
cobalt oxide 3,08
vanadium pentoxide 2,31

   
How do I test my glazes?

Mixing glaze tests: Sieving

Some think it's important to screen after each coloring oxide addition for smoother results. Inexpensive test sieves are available that fit over a jar or half pound margarine cup. Also, some people use permanent coffee maker filters as screens. See how to make your own test sieve here:

Make your own test sieve

   
How do I apply glaze?

Opaque White

Opaque White Glaze
Cone 9-10
Reduction
Potash Feldspar 45.35
Ball Clay 12.85
Whiting 17.5
Borax 1.45
Slilica 20.5
Zinc Oxide 2.35
Zircopax 30.2

   
How do I apply crystal glazes?

Application

The easiest way to apply crystal glazes is to begin by not mixing the jar of colour. Pour off the majority of the glaze on the top of the jar, which will be glaze without crystals. Apply the first two coats of colour from this supply. Let dry and apply the remaining glaze and crystals. You should take care not to apply crystals from crystal glazes too near the bottom of a piece to avoid drippings and puddles on the bottom of a piece. The effects you achieve with crystal glazes will never be the same on two different pieces.

   
How do I make Egyptian Paste?

Egyptian Paste

Egyptian Paste was used, as the name implies, by the ancient Egyptians, as far back as 7,000 years ago. Ornaments made from this material have been found in most Egyptian burial tombs. Egyptian Paste is a self-glazing, low-firing clay body that was probably discovered by accident when a mixture of sand, clay, potash feldspar and soda ash were fired.

Read this entire article in the Articles section of this site 'Egyptian Paste'
Or go to:
http://www.ceramics-tips.com/RscArticleV.asp?id=372

   
What is a glaze?

Copper Green #2

Copper Green
Cone 03
Oxidation
Koalin 13
Dolomite 8
Potash Feldspar 63
Whiting 16
Tin Oxide 4
Copper Oxide 1.2
*See Disclaimer*

   
What are some stoneware glazes?

Matt Glaze

Matt Glaze
Cone 8 - 9
Oxidation or Reduction
Soda Feldspar 40.0
Silica 25.0
Whiting 11.0
Kaolin 12.0
Magnesium Carbonate 15.0

Comment: suitable for Leach Porcelain.

   
How do I apply glaze?

Mottled blue ash glaze

Edouard's Bleu marbré cendré (Mottled blue ash glaze) Cone 4. Thank you to Edouard Bastarache for supplying this glaze recipie.
Nepheline/Syenite 25%
Hardwood ash(washed) 20%
Silica 20%
Ball clay 5%
Gerstley borate 30%
Bentonite 2%
Ultrox 15%
Cobalt oxide 5%

   
What is Glaze starvation ?

Glaze starvation

Glaze starvation results when a piece does not have adequate colour coverage. To correct, simply heat piece in oven , re-apply more glaze and fire again.

   
How do I decorate my ceramics?

Dipping Description

Dipping is probably the most common glazing technique. As the name suggests, a pot or other ceramic object is dipped into a bucket of glaze. This may require a large amount of glaze, depending on the size of the object. If it is a thin necked vase or bowl that is being glazed, the inside may be done first by pouring the glaze in and out again. Then the form is dipped into the glaze with the opening facing down. The trapped air will prevent any glaze entering the already glazed interior. Hint: three-pronged raku tongs are handy for dipping -- they leave only small pin-sized marks which can be smothed over by rubbing.

   
What is an embossing glaze ?

Embossing glaze

Any glaze may be used over embossing glaze as long as the embossing glaze has been fired first.
Embossing glazes are opaque and, if used in too wide and area, can crack in the firing.
Embossing glazes do not flow in the firing process.

   
Can I Fire lustres and china paints together?

Firing lustres

There is a reason for that odour when firing your golds or other lustres. They are suspended in resins and oils so you can apply them properly. During firing, these must be burned out so you will get that fine finish.

   
How do I accent the cracks in crackle glazes?

accent the cracks in crackle glazes.

Black paste shoe polish or ink can be used to accent the cracks in crackle glazes.

   
How do I glaze my ware?

Glaze Application: Spraying

Glaze can be sprayed onto a pot. However, the glaze will probably need sieving through a 120 mesh sieve to allow it to pass through the nozzle of the glaze spray-gun. Spraying is a hazardous process and you must always use an extraction booth that conforms to OH&S regulations. The work being sprayed must always be within the booth and the spray-gun must be directed towards the booth from a distance that ensures that the spray mist is adequately extracted. Spray equipment must be maintained to a high standard.

   
What Precautions when using dry ingredients?

A Disclaimer

Disclaimer: It is the responsibility of anybody using these glaze recipes to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips nor its Ceramic Guru, Jan will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
How do I apply glaze?

Translucent Clear Gloss

Translucent Clear Gloss: Cone 4 - 5 Oxidation
Ferro Frit 4508 60.0
Nephelene Syenite 20.0
Ball Clay 20.0
Tin Oxide 6.0

   
What is the best application of lustres?

Applications of lustres

Thin, even applications of lustres and metallics are necessary. If a deeper colour is desired then re-apply and refire.

   
What is Crawled glaze ?

Crawled glaze Description

Crawled glaze is a condition caused by spots on the bisque that are not covered with glaze. This may be form too heavy and application of glaze, oil from the skin left on the piece or hard spots from polishing greenware. Often the re-application of glaze over these spots and refiring will take care of the problem.

   
What are some stoneware glazes?

Semi matt gray, green and blue

Semi matt gray, green and blue

Color depends on thickness. Very thin glaze is gray, fairly thin green and semi matt. Thicker glaze becomes blue and semi glossy to glossy with small crystals. 1270oC with one hour at top temperature. Very good for incised decoration. Safe glaze.

potash feldspar NR 59,40
whiting 17,50
china clay 4,66
Albany slip (the real thing) 7,30
rutile 7,30
zinc oxide 1,16
quarts 1,46
cobalt oxide 1,46

   
When should I apply a glaze?

Uses

Glazes must be used on anything that will contain water.

   
How do I use sand in glazes?

Textured glaze description

Textured glazes are that family of colours that produce special surfaces when fired.
Textured glazes are often so course they appear to be a gravel stucco finish.

   
What is a glaze?

A Disclaimer

Disclaimer: It is the responsibility of anybody using the above glaze recipies to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips.com nor its Guru, Jan, will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
What is a glaze?

Rusty Red

Salvatoris Rusty Red Black Fire Glaze
Copper Carbonate 60.0
Borax 40
Sodium Bicarbonate 40
Cobalt Carbonate 5.0

Comments: Bisque fire work to 1100o C
Mix glaze same day as firing
Apply glaze thickly
Dribble glaze on thickly for effects
*see disclaimer*

   
will Semi-matte or satin glazes produce antique?

Semi-matte or satin glazes Desc.

Semi-matte or satin glazes are opaque in nature and produce very little antiquing or highlighting effects.

   
What is Stoneware?

Stoneware Glazes Description

Stoneware Glazes (high fired - Cone 4-10)
Stoneware glazes offer a much more diverse range of
colors and textures. They are usually applied by dipping or pouring the glaze over the piece. There are a few glazes with ‘universal' appeal. They are known because of their consistent and predictable results.

   
How do I apply glaze?

Coloured glazes

You cannot tell by looking at a jar of glaze what colour it will look like after being fired.
The firing process matures the components of a glaze to give you the end colour.
Once this is attained however, you can put food dyes into your glaze bottles, this burns out and you can see at a glance what glaze you have used.

   
What is the best way to apply Antique glazes ?

Application

Antique glazes are best applied to pieces with good detail that are not too fine or shallow

   
How do I apply glaze?

Applying semi-matte or satin glazes

The best method of applying semi-matte or satin glazes is to thin the first coat of colour before applying which will help eliminate pinholes.

   
how many coats for textured glazes?

Textured glazes

When using textured glazes, be sure that you are applying the proper number of coats. If you do not apply enough, or if you over-fire your piece, the texture you wanted will be almost smooth.

   
What are textured glazes ?

Textured glazes/ brocades/flairs

Textured glazes (called brocades, flairs, etc.) can be used in combination with most other glazes?

   
What are some stoneware glazes?

Blue texture

Edouard's Bleu texturé #2
Cone 9
Custer spar 38.5%
Whiting 16%
Strontium carbonate 5%
E.P.kaolin 19.7%
Silica 15.1%
Rutile 2.25%
Titanium dioxide 2.25%
Cobalt carbonate 2.4%

Thank you to Edouard Bastarache
for supplying glaze recipie.

   
How do I create a woodtone effect?

Antique glazes

Antique glazes will produce from two to three shades of the same colour.

   
How do I create a third colour?

create a third colour

It is possible to create a third colour by mixing two different coloured glazes together. It is advisable, however to fire a sample chip after mixing to be sure that you have the colour you want.

   
Can antique glazes be applied too thinly?

Too thin an application

It is possible to apply antique glazes too thinly, which will eliminate the frosted look.

   
How do I apply glaze?

Clear glaze

Since clear glaze is the most frequently used and it is often to tell which coat you are on, it is possible to colour it with food clouring and use a different colour for each coat.

   
What are some stoneware glazes?

Recipe: Glossy orange yellow

Crystal glazes: Glossy orange yellow
A colorful crystal glaze based on zinc and lithium. Too thick it will run a lot. Spray the glaze thinner near the bottom of the pot. 1260oC with 1/2-3/4 hour at the top temperature. Does not need a slow cooling. Try a second burning. Try also more ferric oxide.
potash feldspar NR 28,80
quarts (flint) 33,00
dolomite 3,57
zinc oxide 19,50
barium carbonate 4,67
china clay 2,75
lithium carbonate 7,70
rutile 2,20
red ferric oxide 2,20

   
How do I avoid contamination?

Under-fired lustre

If you remove a piece from the kiln that you applied liquid bright gold to and it rubs off the piece, it has been under-fired.

   
How do I apply glaze?

Description

What is a glaze?
We're all familiar with glaze as a coating of glassy material on the surface of a pot. A glaze is exactly that, though we may not recognize some types of glazes as particularly glassy. Glazes can be glossy, matt, rough, and all variations in between. They can also be transparent, translucent, or opaque and may have most any color. A glaze can show depth--in gradations of color for a transparent glaze, or in the surface itself for some special effect glazes such as crater or crawl glazes.

   
What are some stoneware glazes?

Limestone Glaze

Limestone Glaze
Cone 8
Oxidation
Potash Feldspar 40.0
Silica 30.0
Calcite 20.0
Kaolin 10.0

   
What safety aspect should I keep in mind when working with glazes?

A Disclaimer

Disclaimer: It is the responsibility of anybody using these glaze recipes to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips nor its Ceramic Guru, Jan will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
How do I glaze my ware?

Glaze Application: Painting

Glaze can be painted on, and this offers enormous potential for decoration. Any brush can be used, but glaze mops, flat lacquer brushes and Japanese hakes are particularly useful for covering large areas.

   
What are some stoneware glazes?

Shino glaze

Shino glaze

Use only on brown stoneware clays with or without lava or pyrite. Do not work on white or gray clays. Apply normal to thick. 1260-1280oC with good to heavy reduction.
nepheline syenite 33,33
ball clay 33,33
wollastonite 33,33

   
How do I prevent glazes from settling ?

To prevent glazes from settling

To prevent glazes from settling rock hard, add a small amount of Epsom Salts (Magnesium Sulfate) to the glaze. Depending on the glaze composition, it may hardly settle at all, or if it does, be easily stirred again.

   
How do I decorate my ware?

Air-brush(Emergency)

If you need and emergency airbrush, try using a spray bottle, insect sprayer or even your vacuum cleaner.

   
Can Crackle glazes be used for food?

Crackle glaze: application

Contrary to most other glazes, crackle glazes only require two coats in application.

   
How do I create a woodtone effect?

Application

When using woodtone glazes, be sure to brush out the specks you find in the glaze. These specks, when broken and brushed on (all in one direction), will create a woodtone effect.

   
How do I apply Lustres?

contamination

When working with lustres, all forms of contamination must be avoided. The work area and object must be free of dust dirt and moisture

   
What are speckle glazes ?

Speckle glazes description

Like the name implies, speckle glazes produce just that effect. In the application of the colour, you will note little specks or crystals that are applied in each coat of glaze. When fired, these specks produce a varied effect, often called oatmeal.

   
What is Stoneware?

A Disclaimer

Disclaimer: It is the responsibility of anybody using the above glaze recipies to be informed of glaze dangers and to ensure the proper safety precautions are met when mixing and using glazes. In general glaze components marked 'toxic!' should not be used for tableware. Other, not marked ingredients may be harmful to health on skin contact or if ingested. Frits may contain Lead Bisilicate. General safety precautions for ceramic materials apply. Contact a supplier, lecturer or professional if in doubt. Neither Lifetips.com nor its Guru, Jan, will bear any responsibility for incorrectly used glazes and/or ingredients, nor for any damages due to unexpected glaze results. All glazes should be tested before use.

   
How do I apply Lustres?

cleaning lustre

Metallic glazes such as overglazes and raku glazes, will oxidize over time. The oxidation can be cleaned with silver polish, or concentrated lemon juice. To reduce oxidation, keep pieces out of the sun.

   
What can I expect from Art glazes ?

Effect

Art glazes are formulated to break into a multi-coloured effect during the firing process produced by the runs during firing.

   
What are some stoneware glazes?

Recipe: A fat Celadon

Reduction:

Celadon glazes and similar:

92187 Fat greenish gray Celadon

A fat Celadon at its best when thick. No crackle. 1260-1280oC in normal to heavy reduction. Semi matt. White and colored stoneware clays.
potash feldspar NR 38,10
china clay 7,90
quartz (flint) 28,60
whiting 15,90 talc 9,50
red ferric oxide 1,10

   
What is bone ash?

Bone ash: Description

Bone ash is ground bones, usually cattle bones. It is one source of calcium phosphate; others are phosphorite and apatite. It is used as a flux in bodies where the calcium oxide does the fluxing and the phosphorus oxide acts as a glass-former in the melt and also checks over-rapid fusion. Its stiff glassy character is seen combined with that of feldspar in bone china. Bone china contains 45 – 50% of bone ash. A small amount of carbon remains in bone ash when calcination is controlled and this carbon assists the raw plasticity of the body.

   
What are Halos?

Halos

Halo Gold, Halo Platinum or Halo Copper firing purple, brown, or blue is caused by too light a colour of glaze. In order for these metallics to work, they must be applied over a darker glaze.

   
How do I apply crackle glazes ?

Crackle glaze: development of crackle

The crackle effect of a crackle glaze begins to develop even before you remove pieces from the kiln and will continue long afterwards.

   
how do I achieve the desired glazing results?

Speckle glazes

When using speckle glazes, be sure to stir the jar thoroughly to guarantee the specks will be distributed throughout the glaze.

   
What is majolica?

majolica is the technique of painting over opaque glazes

Did you know that majolica is the technique of painting over opaque glazes? Also refers to opaque tinted glazed ware.

   
How do I apply glaze?

Brush marks with matt glazes

Brush marks will show when a matte glaze is fired, so be sure to smooth each coat of colour with fingertips before applying the next.

   
What are some lustre effects?

lustre effects

For a special technique, you can over-fire a metallic. Fire it hottter than normal and the glaze will begin to move, making the overglaze move as well developing voids that allow the colour of the glaze to show through.

   
How do I get glaze to adhere to a porcelain piece?

To get glaze to adhere

To get glaze to adhere to a porcelain piece, it is necessary to use high-fire glaze

   
What is Frit?

Frit

Those little chunks of colour that are found in crystal glazes are called frit. They are pieces of dried glaze.

   
What is Flux?

Flux description

Did you know that flux is added to glazes to reduce the speed and maturing temperature of glazes during firing?

   
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Guru Spotlight
Jennifer Mathes, Ph.D.