Glossary

Slip

A thick and creamy mixture of clay and water used to join clay parts together OR to decorate the surface. It is applied before firing, when the clay is still plastic or leather hard.

Oxide

A finely ground raw material (a metallic oxide) used in ceramics as a colorant, flux, or glass former. Examples include iron oxide, copper carbonate, titanium dioxide, rutile, etc.

Stain

A proprietary mix of oxides produced by industry and sold in a variety of colors. Stains tend to be more stable and come in a wider range of colors than do raw oxides.

Underglaze

A mixture of ceramic color that can be applied to wet, dry or bisque clay. The pre-fired color of commercially prepared underglaze stays true through the firing. Underglaze has no glass former so it is not shiny when fired. A clear glaze can be applied over underglazes if a shiny surface is desired.

Wash

A thin solution of the same metallic oxides that are used to color glazes. A wash can be applied under or over a glaze. Applied first, it can be rubbed into the carving and textures, picking up details; applied over a glaze, it can fuse and flow as the glaze melts, giving a softer result.

Sgraffito

Sgraffito is a decorating technique developed centuries ago. In its simplest embodiment, leather-hard clay is coated with an engobe (or slip) of contrasting color and then a pattern or picture is added by carving through or scraping off the slip to reveal the clay underneath. Similar to the 2D technique known as “scratch art”.

Mishima

A decorative technique where a design or pattern is incised, or carved, into the clay, filled with a contrasting colored slip, allowed to dry and then sanded to reveal the original design filled with color. Inlay designs are typically covered with a transparent glaze.

Leather hard

Clay that has been allowed to dry slightly, making it stiffer and able to support its weight, but which can still be worked on and have parts attached. It is the ideal stage for incising.

Wax Resist

In this decorative technique, patterns or designs are created by brushing a wax medium over an area of clay, slip, or glaze to resist the final glaze application when the wax is dry.

Incise

To cut a design or decorative mark into the clay.

Engobe

A colored slip, it is applied to wet clay for decoration.

Surface Treatment

Any of a variety of techniques used to create interest on the surface of a ceramic work; the way the surface is treated, textured, decorated, colored, and/or glazed.

Terra Sigilatta

Terra sigillata is an ultrarefined clay slip that can give a soft sheen when applied to bone-dry wares and, if polished or burnished while still damp, may give a high gloss. The ancient Greeks and Romans used this technique in lieu of glaze.

Material

Quantity

Borax

5

Talc

5

Nepheline Syenite.     

16

Ball Clay

26

EPK

26

Flint

21

Zircopax

10

Total

109

Water

6 # 8 oz.

Sodium Silicate

4 drops

clay

1000 g

water

3000 g

Calgon

2-5 g