Ceramics

bat

a base for throwing, hand-building, or drying; usually made of plastic, pressed board, plywood or plaster

celadon

a category of green, gray, or blue-gray glazes for stone ware and porcelain; developed in China and Korea

glaze

a coating of glass that is fused to the surface of a ceramic piece

carbonates

a compound containing carbon and other elements, used in making and coloring glazes or clay bodies

oxide

a compound containing oxygen and other elements, used in making and coloring glazes or clay bodies

sgraffito

a decorating in technique where a layer of slip applied to a clay body is scratched through to reveal the clay color

sprig

a decoration in relief, attached to greenware with slip

rib

a flat curved tool made of wood, metal, or plastic used to refine shapes

slip

a fluid suspension of clay in water used in joining clay pieces and for surface decoration

overglaze

a glaze designed to be applied and fired at a lower temperature after the first glaze firing

pinching

a hand-building technique that involves squeezing the clay, usually between fingers and thumb

peephole

a hole in the door of the kiln through which the potter can view the progress of the firing

downdraft kiln

a kiln where the heat and flames are drawn downward and out through openings at the base of the kiln

fettling knife

a long, tapered knife used for cutting and trimming clay

flux

a material that promotes melting or increasing the glass-making qualities of a glaze

clay body

a mixture of clay, minerals, and other ingredients compositon

pigment

a mixture of minerals painted on clay ware before or after firing to produce color

alumina

a primary ingredient in clay and glazes

kiln

a structure built to fire clay at high temperatures

ware

a term for any ceramic

luster

a type of decoration made when metallic salts fired at low temperatures given a metallic sheen to a body or glaze surface

updraft kiln

a type of kiln where the heat is drawn through the kiln and exits through the top

colbalt oxide

a very strong oxide used to produce blue in slips and glazes

kneading

a way of mixing larger pieces of clay to distribute minerals, organic materials, and water evenly and to eliminate air bubbles

wedging

a way of preparing small or medium-sized pieces of clay to improve work-ability and eliminate air bubbles

silica

a white or colorless crystalline compound occurring abundantly as quartz, sand, flint, agate, and many other minerals. It is a sparkly material in sand

colorant

an element or compound that contributes color to a slip, glaze, or ceramic surface

firing cone

an object made of ceramic materials with a specific melting point, used to show the temperature in a kiln during the firing; will bend at the desired firing temperature

flue

an opening within a kiln through which hot gases pass from the chamber to the chimney

underglaze

any coloring element, such as oxides or commercial colorants, applied prior to glaze application

mold

any form used to shape clay

inclusion

any part of a fired clay piece, such as plant remains, rock fragments, and temper, that was not originally a clay mineral

setting

arranging ware in a kiln for firing

coiling

attaching rolls of clay together to form pottery

bisque

ceramic ware that has gone through the first firing at a relatively low temperature (generally cone 010 to 05) and still maintains its porous state

grog

crushed, fired clay used as an additive to reduce clay shrinkage

stoneware

dense, nonporous, hard pottery that matures from cone 5-11 (2200-2400 degrees Farienheight

majolica

earthenware covered with a tin glaze and painted with oxides

oxidation

firing when the amount of oxygen present is more than is necessary to combust the fuel

earthenware

glazed pottery that remains porous when fired at low temperature (below cone 2)

slab building

hand-building technique that involves shaping clay into a broad, flat, thick piece

traditional pottery

hand-built ceramics decorated with natural pigments and fired with organic fuel

kiln furniture

heat-resistant shelves and post used to hold ware during firing

firing

heating pottery or clay sculpture to a temperature high enough to render it hard and durable

atmosphere

mixture of gases in a kiln environment

ceramics

objects made from clay that permanently retain their shape after they have been heated to specific temperatures

burnishing

polishing the surface of a leather-hard pot to compact it and produce and maintain a sheen at low firing temperatures

scoring

scratching the edges of clay before joining them together

relief

sculptural or decorative forms that project from a flat background

bone dry

stage of drying when moisture in the clay body has evaporated so the clay surface no longer feels cold

porosity

the amount of empty space in the structure of the fired clay that makes it capable of absorbing liquids

foot

the base of a pot upon which it can stand

aesthetics

the branch of philosophy that deals with issues of what is considered to be beautiful and what is considered to be art

drying

the elimination of water from clay pieces before firing

chamber

the enclosed portion of a kiln where pottery pieces are placed for firing

neck

the part of a vessel between lip and shoulder

plasticity

the property of clay that allows it to change shape without tearing or breaking

shrinkage

the reduction in size of the clay mass, occurs when water in the clay evaporates during drying and firing

lip

the rim opening of a pot

leather hard

the stage between plastic and bone dry when clay has dried, but may still be carved or joined to other pieces

vitrification

the stage during firing when a clay or glaze loses its porosity and transforms into a hard, nonabsorbent, glass-like state

inlay

to fill an incised or impressed area with contrasting colored clay

incise

to remove clay by carving

raw clay

unfired clay

greenware

unfired pottery or sculpture

melting point

when a clay fuses and turns to a fluid glass-like substance during the firing