Welcome to Ceramics Tips

Troubleshooting: Dull lustres/metallics

Cloudy or dull lustres or metallics may be caused by insufficient ventilation or firing to an excessive temperature.

Terra sigillata: Application and Firing

Application and Firing: Terra sigillata can be applied by spraying, dipping or brushing at all stages of construction. Apply several coats and burnish or simply polish with your hands or a soft cloth when damp/dry to the touch. Polish between coats for the glossiest surfaces. Terra sigillata can be fired at any temperature but the polished surface will start to break down when fired over cone 04. Use as a slip/engobe up to cone 10 and above.

Ceramics Decoration

Once you have the piece you want and have completed the necessary processing, you are ready for ceramics decoration. There are so many styles to choose from that you may want to start simple and develop your own unique style after some experience. Glazes run the gamut from the simple to the sublime using chemicals, metals and other compounds to achieve incredible results. The most important part of ceramics decoration - have fun!

About Decals

Decals are available in a huge array of designs and colors, and can be adapted to almost any project with little effort. Technically, decals are overglazes and may be made of china paints, gold, platinum or enamels. They are applied over a fired glaze surface, glass or porcelain bisque, then re-fired. During the firing, glazes soften and most decals sink into the surface and become a permanent part of the item. Metallic decals fuse to the glaze, but remain on top of it, and may wear off as time passes.

Description

Engobes can be defined as liquid clay slips of varying compositions which are applied to the surface of a clay object, e.g. a pot. The purpose of the engobe can be as different as the varied forms it comes in: to give color to a piece; to improve the surface texture; to provide a ground to do further decoration on; to add textures.
Engobes can be applied to wet clay surfaces, leather-hard ware, greenware and even bisqued wares. In each case the engobe´s shrinkage rate should match that of the clay underneath, otherwise cracking (when the engobe shrinks more than the clay underneath) or shivering (when the clay underneath shrinks more than the engobe on top) can occur. While there are some basic engobe recipes around, The Potter´s Complete Book of Clay and Glazes by James Chappel has a range of engobe recipes for diferent grades of moisture content and firing ranges from cone 10 up to cone 11

Terra Sigillata: History

History: Historically terra sigillata has been used as a sealer and decorative coat on pottery for thousands of years. Common examples are the Roman red black pottery, and the black polished Native American Indian pottery of the Southwest. Contemporary uses include raku, smoke firing and other techniques that emphasize the surface.

using underglazes

When using underglazes, do not backstroke when applying, as this will cause a pile-up of paint or a pulling off of the paint already applied.

drying underglaze

Remember that your colours must be dry before taking any nest step, whether it is firing or adding design work over your underglaze base.

Woodgrain finish with stains

A special effect of woodgrain can be accomplished easily. Simply cover the entire piece with your choice of colour and wipe piece down with a wrinkled piece of newspaper. Be sure to do your wiping in one direction. The newspaper will absorb some colour leaviing woodgrain streaks where the colour remains.

Colour Development

Colour Development
Cloudy looking decals or decals where the colour is not bright need to be burned out and carbon monoxide fumes have to be removed from the kiln. Manual venting by propping the lid and removal of peephole plugs will improve the firing, but may not help bring enough air to the bottom of the kiln or to distribute it evenly throughout the load. A downdraft vent system will ensure sufficient air is brought into the kiln and circulated throughout.

Waterproofing

- Tung Oil (available in hardware or woodworking stores - Thompson´s Water Seal (available in hardware stores, used for sealing wood and concrete) - Acrylic Floor Polish (ie Futura.) (available in the grocery store.) Note that I would not use any of these for dinnerware. Just for vases, flowerpots, etc. And some people use them over glazes just to get a nice subtle shine. And I have been known to use them on the bottom of pots to make them less likely to scratch furniture. Another reason potters want sealers is to protect painted work. For example, people that use acrylic paints on bisque and want to protect the paint. We do sell Duncan spray and brush-on sealers in flat and gloss, which will protect the paint from chipping and smudging, and give it a shine if you wish. They are good for decorative pieces. But these are not waterproof. So if you want your piece to be waterproof, try one of the above products. But since those items work by penetrating the clay, and they probably won't penetrate through the acrylic paint, I would put it on the inside of the piece, then protect the painted outside with an acrylic spray sealer like the Duncan products (or similar items available in the hardware store.) So for example, if you want to waterproof a flowerpot, put the tung oil, Thompson's water seal, or acrylic floor polish on the inside of the pot. Paint and seal the outside.

Thin pieces

When glazing a thin piece, glaze the inside, making sure you don´t over apply, as the thin walls will absorb a lot of glaze, then wait for it to dry thoroughly before glazing the outside. Otherwise the clay may be saturated and glaze won´t absorb and stick to the outside. Some people wait overnight.

Terra-Sigillata: Description

Terra-Sigillata is a slip, made of clays whose particles are extremely fine. Like slip or en-globe - which it basically is - Terra-Sigillata appeals to those who wish to develop an intimate relationship between the surface of their work and its form, and who respond to the way in which the Terra-Sigillata becomes an integral part of the clay body rather than coating the surface like a glaze. After the final firing the forms are hand-polished with Tung Oil to achieve a more durable surface. Terra-Sigillata means "sealed earth". It was used by the Greeks and Romans before the invention of glaze.

Attaching pulled handles

Attaching pulled handles: Once all handles are pulled and firmed, (approx.1/2 hr), they are ready to attach. I will describe this process as connecting to a mug, though it is the same procedure no matter the form. 1. Take handle and flatten the large end with a flat piece of wood ie ruler, wooden spoon back. 2. With a fork or other tool cross hatch both the flattened end of the handle and the point on the pot you wish to attach the handle, with an old toothbrush, wet these areas with water or slip. 3. Attach the hatched end to the pot and press and wiggle it gently until you feel adhesion 4. Pick up the pot and hold arm extended as when pulling the handle, and continue pulling in the same way until desired thickness, squeeze off any excess clay and join other end to pot by pushing into place. 5. Leave upside down to dry. Note: Handles dry faster than ware, so keep them covered with plastic or put on ware board with all handles facing inward.

Drawing Directly

You can draw directly onto a pot by placing design over carbon paper and tracing the design, you can also sketch right onto the surface with pencil as the lines will burn out in the firing.
hope this has helped!

Oxide over glaze effortlessly

When applying oxide over dry glaze, the glaze sucks the water out of your brush making it difficult to paint clean lines. Lightly mist the glaze first with water, and the oxide will flow smoothly.

10 Oxide Experiments

Here are 10 ways to experiment with oxides.
1. Brush oxides on greenware, bisque and/or glaze.
2. Make some slip and add some oxides to create colors. To get more uniform colors mix well.
To get more random, blotchy colors don't mix too well.
3. Brush oxide wash over an unfired glaze, then fire. Be very careful when handling as you may smudge the oxide.
4.. Brush oxides on, then apply glaze. Best to dip or spray to avoid brushing the oxide off (and if dipping, best to put some glaze aside so oxide doesn't contaminate your whole batch of glaze.)
Generally the stronger the oxide wash, the more it will bleed through the glaze.
* Both 2 and 3 works well with Opulence glazes, and many of the other glazes. Where specified by the manufacturer this is explained on the label.
5. Mix ball clay with your oxide/water. Is reported to gives a better consistency and tones down the color.
6. Brush a couple different oxides on, overlapping in areas.
7. Sgraffito. Brush on oxide. When dry, scratch with a sharp tool through the oxide to show the clay underneath. Cover with transparent or translucent glaze. Or do the same thing with oxide over unfired glaze.
8. Spatter wax on the surface, and paint the oxide wash over that.
9. Use other masking techniques, such as torn, wet newspaper, and paint an oxide wash over it.
10. Sprinkle a variety of different oxides on a newspaper. Place leather hard objects onto the oxide mixture (for example, a piece of tile). Or use a piece of Styrofoam or a sponge to pick up the oxide and transfer it to your piece. Keep the pattern as it lands, or smear it around. In this bisque and apply glazes; the oxides will still interact with the glazes when fired together.

Cloth for texture

Cotton lace, burlap, cheesecloth or other cotton, absorbent materials can be soaked in slip and added to pieces for interesting textures. Soak fabric in slip, squeeze out lightly, brush on leatherhard clay surface, dry slowly, and bisque. The fabric will burn out leaving the slip texture behind.