Question:

How do I fire Decals?

Thickness

Thickness of the piece.
Air has to penetrate through the entire thickness of the piece and the gases have to escape the same way. It takes longer for carbon to burn out of a thicker piece of ware.

How Carbon Burns Out

How Carbon Burns Out
During heating (firing) the carbon reacts with oxygen to form carbon dioxide and carbon monoxide gases. The carbon leaves the body as a gas. Binders are burned off at a relative low temperature: 300║F to 500║F.
Naturally occurring carbon in clay burns off (becomes gases) at higher temperatures: up to 1200║F - 1400║F.

Precipitating burnout

Slow Down Firing
Be sure the kiln is vented adequately so there is sufficient oxygen.
Load the kiln with burn out requirements in mind.
Leave plenty of space between ware and shelves. Do not stack ware. Use tile and plate stackers and invert pieces on top of one another to help conserve space and insure proper burnout.

Measuring Heat Distribution

Differences in heat distribution from top to bottom in the kiln are usually far more noticeable for cooler firings like decals. A 2 or 3 cone difference at 022 may only be a 1 cone difference at cone 6. This is because at higher temperatures radiation heats the kiln more effectively. Slowing the first half of the firing can help heat distribution problems. This also helps by allowing more time for air to enter the kiln and burn out organics and for carbon monoxide to leave the kiln. Use a controller to set heating rates and soaks for more precise firings.

Carbon burnout rate

The rate at which this carbon burns out is related to:
The amount of carbon present (that is, the amount of natural contaminants in the body). Some bodies have more contaminants than others, such as red clays. This needs to be considered when planning the firing.
Amount of air available (air provides oxygen for burnout) Air needs to be considered when planning the firing.
This is impacted by several factors. A load that is fired very quickly will not allow enough time for the oxygen to react with the carbon, form gases and leave the ware. If ware is stacked during bisque firing, oxygen may not be able to penetrate all surfaces of or inside all the pieces. Also, if gases are not removed from the kiln and replaces with fresh air, then there may not be sufficient oxygen to burn out the carbon.

Time and temperature

Time and temperature profile during the burn out period. Both time and temperature are important for proper burn out of the carbon. Some carbons require much higher temperatures that others. Oxidation should be completed below red heat (1400║F). Carbon burns out from the surface first. As more oxygen penetrates the body, them more carbon is reacted to form the CO or CO2 gas and the burn out process continues. If there is sufficient time, temperature and oxygen, then complete burn out occurs. If these conditions do not exist, the resulting incomplete burn out is referred to as black coring (where the center of the piece has black or gray cast).

Measuring Heat Distribution

Measuring Heat Distribution
Differences in heat distribution from top to bottom in the kiln are usually far more noticeable for cooler firings like decals. A 2 or 3 cone difference at 022 may only be a 1 cone difference at cone 6. This is because at higher temperatures radiation heats the kiln more effectively. Slowing the first half of the firing can help heat distribution problems. This also helps by allowing more time for air to enter the kiln and burn out organics and for carbon monoxide to leave the kiln. Use a controller to set heating rates and soaks for more precise firings.

Measuring Heatwork

Measuring Heatwork: Heatwork is another critical factor in the colour development of decals. Fading, Shifting and dullness are signs of too much or tool little heatwork. This is also true when decals rub off after firing. (White or blank spots or burned off areas are generally related to application, not firing.) Use witness cones to measure heatwork and to check the heat distribution in the kiln. Firing to a temperature or firing to a Kiln-Sitter cone may not give the same results as found with a witness cone next to the ware.

Determining Firing Range

Determining Firing Range
Because the colours on decals can so easily be affected by the amount of heatwork they receive, we recommend test firings to determine the best firing range.
Use a series of witness cones to fire samples of the decals on tiles or blanks. Make several firings and then select the fired appearance which looks the best.

Incomplete Burn Out

Incomplete burn out can result in several firing problems including: Bloating of the ware - if the temperature is hot enough, the outside of the piece will seal up before all the gases can escape. As the body becomes plastic due to glass forming, gases trapped inside the body expand with heat and cause bloating and sometimes cracking of the ware.
Glaze defects, such as pinholes - the escaping gases will push through the glaze surface and cause bubbles which pop. If these do not heal, then pinholes will result. Appearance of fired bisque - where carbon burn out is incomplete, the piece will have a grayish cast (white bodies) or may have greenish cast (red bodies). The body will also be more porous and weak.

Carbon burnout

Carbon burnout: Materials used in ceramics contain naturally occurring impurities that can affect the colour, appearance and maturing temperature of the product. Carbon, found in most clays, is normally considered one of these impurities. Carbon can also be present in the additives and binders which make up clay bodies, slips, decals and lusters.

Ceramics Frequently Asked Questions

What precautions should I take in the studio?

How do I decorate my ware?

How do I apply Lustres?

How do I market my ceramics?

How do I apply glaze?

How do I market my ceramics?

How do I fire porcelain?

How do I cast slip?

How do I fire an electric kiln?

How do I apply glaze?

What are some stoneware glazes?

What Precautions when using dry ingredients?

How do I apply glaze?

How do I apply opaque stains ?

How do I wedge clay?

How do I apply Stains?

What is Lustre?

What should I keep in mind when designing my studio?

How do I make a coil pot

How do I decorate my ware?

How do I make molds?

What is Clay?

How do I apply glaze?

What is a decal?

How do I clean Greenware?

How do I add texture?

How do I centre my clay?

What tools do I need to start potting?

How do I start a business?

How do I best promote myself and my work?

How do I load my kiln?

What are ceramics

Where do I start?

How do I make a simple mold?

How do I fire Decals?

How can I make a mould?

What are some life quotes?

What is underglaze?

What is Porcelain

How do I care for my brushes?

How do I care for my molds?

What is Celadon?

What is the Tea Ceremony?

How do I care for my kiln?

How do I apply one-strokes?

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

How do I apply Lustres?

What is Overglaze?

What are oxides?

How do I fire Bisque?

Where do I begin?

What should I remember when firing the kiln?

How do I clean brushes?

How do I slump/sag glass?

How do I apply overglazes?

How do I best publicise my business?

How do I make a simple plaster mold?

How do I care for my brushes?

Are stains safe.

How do I fire overglazes/lustres?

What is a reduction firing?

How do I doccument my work?

How do I create fine feature lines?

How and when sholuld I apply underglazes?

How do I make molds?

What is an engobe?

Are they Water or oil base stains?

How do I hold my brush?

How do I store my Materials?

Are any two kilns are exactly alike?

What is mould in clay?

What is a Pyrometric Cone?

Do I need a cone?

how do I throw clay?

Can I use sand to stop glaze running onto shelves

How do I test my glazes?

How do I apply China Paints?

Does greenware need to be dry before loading?

What are some life quotes?

What is the history of the Potter┤s Wheel?

How do I fire lustre?

What is a glaze?

How do I fire lustres?

What is The History of the Way of Tea

What is Celadon (Cheong-Ja) - the Stuff of Kings?

How do I dry overglazes?

What is a glaze?

How do I Burnish?

What is an overglaze marbleizer?

Is there a trick toThrowing Porcelain?

Have you some lovely words?

What is Earthenware?

What is a glaze?

What are some stoneware glazes?

How do I paint Eyes?

How do I Recycle Clay

How do I attach wet pieces?

How do I make a teapot?

How do I make a plaster mold

What are some good tools for decoration?

What is Kiln Wash?

How do I glaze my ware?

How do I slipcast ceramics?

What are some life quotes?

how do I dry my ware?

How do I fire my ware?

How do I apply texture to my piece?

What is a Glost firing?

How do I make my own glazes?

What are some change quotes?

How do I store my tools?

What is the history of Raku?

What is Paperclay

What is a crackle glaze?

Do I need kiln wash for bisque?

How do I refire a glazed piece ?

What is reduction?

What must I remember when Raku firing?

How do I add decoration to my ceramics?

How do I care for my elements?

Does over firing produce poor colour in coloured glaze?s

How do I use my brush?

How do I care for my brushes?

How do I recycle clay?

What are some success quotes?

What is a glaze?

How do I clean Greenware?

How do I make coils?

What are some Black Firing Tips and Tricks?

What is the safest way to pack my ceramics?

What are Formulated clays?

How do I do a reduction firing?

automatic kiln sitter, should I trust it?

How do I care for my molds?

What are some tips for draining a mold?

What is a decal?

What safety measures should I take with Raku Firing?

How do I attach a bat to the wheelhead?

What tools do I need for ceramics

What are suggested plate clay weights?

What do I need to get started?

What are observation holes ?

What tools do I need to make a coil pot

How do I fire ceramic bisque ?

How do I recycle batches of clay quickly

How do I care for my molds?

How do I fire my ware?

How do I roll a slab?

How do I fire my kiln?

What is the correct firing time?

How to I prepare and make slabs?

What is Leatherhard ?

What materials are toxic in Ceramics?

How do I fire glaze?

What are slabs?

What is Korean celadon?

How do I fire Raku?

How do I make paperclay?

Can Crackle glazes be used for food?

How do I avoid S cracks in wheel thrown ware

how do I apply glazes?

How do I get the press onside?

How do I open-up the clay?

How do I fire Reds/Yellows?

What is a glaze?

How do I fire Ceramic glaze ?

Can I repair my kiln?

What are the Approx. firing times?

Ho do I avoid pitting and pinholes?

How do I make throwing ribs?

What is Stoneware?

How do I care for my molds?

How do I apply kiln wash?

What is a Stain?

What is a mold?

How do I decorate my ceramics?

How do I remove mold lines?

How do I cut the spare?

What is a ┤good teapot┤?

How do I Bisque fire in an electric kiln?

How do I keep a kiln log?

How do I paint Eyes?

How do I decorate my ceramics?

How do I apply crackle glazes ?

What is Primary clay?

What are some easy projects?

What is Thermal Shock?

What effects can I achieve with a brush?

What are cones?

How do I Drain small pour holes?

What is Glaze?

What is Raku?

How do I remove a stuck lid?

How do I glaze my ware?

How do I make Egyptian Paste?

How do I apply texture?

What is overglaze/lustre?

Must my kiln be level?

How do I make my own brushes?

What clay should I use?

How do I apply a decal?

How do I clean my greenware?

What is Agate ware?

How do I care for my new Kiln?

How do I make stamps?

How do I load my kiln?

How long do I fire bisque?

How do I promote my work?

can I draw directly onto a piece?

How do I increase my profile?

How do I fire different bodies?

what is porcelain?

How do I make test tiles?

What is Earthenware?

What is the humming in my new kiln?

What should I remember when firing a new kiln?

How do I mend Greenware?

how do I get the best results in glazing?

How do I prevent dirt on my greenware?

How do I accomodate Clay Storage in my studio?

How do I fire Larger pieces ?

How do I prevent sagging during firing?

How do I brush one-strokes?

How do I load my brush for applying underglaze?

How do I mend molds?

Why should I use pottery plaster?

What is the coat coverage ?

How do I prevent glazes from settling ?

How do I fire lace figurines?

What is Albany slip?

How do I create a woodtone effect?

How do I light my Gas Kiln?

What is a pyrometer?

What is a Binder?

What is a glaze?

What are some Doing well Quotes?

What is Slip casting?

What is a Rib?

What is a Bisque?

How do I care for my elements?

How do I fire porcelain?

How do I store my throwing tools?

What is the History of tea?

What is the history of Ceramics?

Why do I get black spots in my glaze?

How do I fire flat pieces?

What is Terra-Sigillata?

What are Pyrometric Cones?

What is Iron Oxide?

How do I load my kiln for a glaze firing?





Not finding the advice and tips you need on this Ceramics Tip Site? Request a Tip Now!


Guru Spotlight
Lynne Christen