Ceramics Vocabulary

ceramics

ceramics

the art of making things of clay

clay

A decomposed granite-type rock. To be classified as clay the decomposed rock must have fine particles so that it will be plastic (see definition below). Clays contain impurities which affect color and firing temperatures.

wedging

Process of kneading clay to make it homogenous; ridding the clay of all air pockets.

greenware

Unfired pottery that is bone-dry. A state in which clay forms are the most fragile.

bisque fire

The first firing of the clay done before glazing. The approximate temperature of this firing is 1880 F.

bisque

unglazed clay, fired once at a low temperature

leather hard

Refers to clay that is dry enough to stand alone but still damp enough to be joined to other pieces or carved without distortion. Clay in this state resembles leather. Hard to bend and soft enough to be carved.

bone dry

Refers to clay which is ready to be fired. All the moisture is gone from the clay. Clay is VERY FRAGILE at this stage.

kiln

Enclosed containers of various sizes- built of refractory brick and heated by electricity, gas, oil, or wood to temperatures from 1500 F. to 2340 F. in which ceramic ware is fired. Also called the “oven” for firing the clay.

fire

term used for baking work in a kiln

handbuliding

One of the oldest craft techniques in which objects are constructed entirely by hand.

form

Three-dimensional shape and structure of an object.

pinch technique

Hand building technique in which a ball of clay is pinched from the center out with the thumbs to create a bowl shape.

coils technique

Hand building technique in which the object is built up with rope like pieces of clay, one on top of another.

slab technique

Handbuilding technique in which flat pieces of clay are joined (clay is flattened and thinned with a rolling pin)

scoring

Roughing up of the surface of clay for joining.

slip

A liquid form of clay used as a glue or as decoration.

glaze

A glassy coating that has been melted onto a ceramic surface. It is used to decorate the piece and to seal the clay surfaces.

underglaze

Colored decoration applied to bisqued clay, then coated with a clear glaze. Typically made of clay slip or raw pigment.

matte

not shiny

glaze firing

The second firing of a piece of pottery which has been coated with glass forming materials. The approximate temperature of this firing is 2300 F.

incising

Carving designs into a surface.

texture

high or low patterns created by pressing or carving down into the clay

sgraffito

decorating technique achieved by scratching or carving through a layer of slip or glaze before firing to expose the contrasting clay body beneath.

cone

A type of thermometer placed in the kiln to indicate when firing is complete. The cone is made of glaze materials and will bend to indicate the end of a firing. (we fire between cones 04-06 which is approx. 1800-2300 degrees).