25
GLOSSARY
BISQUE
- Any fired undecorated clay object.
CERAMICS
- a general term applying to any fired piece of clay material.
CHINA
- A translucent high fire ceramic body.
CLAY
- Earth that is relatively pure silica and alumina; usually a blend of different clays and minerals, combined to achieve
various effects and different properties.
CONE
- see pyrometric cone.
CRATERING
- Imperfections in glaze caused by rapid cooling, which “freezes” bubbled glazes before they can smooth
out, leaving pits.
CRAZING
- A network of hairline cracks in a glazed surface which appears after firing.
DECAL
,
CERAMIC
- A design or picture, usually overglaze, which is applied to and fired onto the ware.
DRY-FOOTING
- Wiping glaze off of the base of objects before firing. This is an alternative to stilting glazed ware to
keep the piece from sticking to the shelf when firing.
EARTHENWARE
- Porous ware made of low fire clays.
ELEMENTS
- Coils of wire having high electrical resistance and resistance to high temperatures which serve to convert
electrical energy to heat in the kiln.
ENAMELING
- Application of finely ground colored glass to metals (usually copper or silver) resulting in a glaze-like
finish after firing.
FIREBRICK
- refractory blocks used in making the insulating firing chamber of the kiln.
FIRING
- Applying heat to ceramic materials to cause a change in their chemical composition (see maturity).
FIRING CHAMBER
- The space in the interior of the kiln where the ware is heated.
FURNITURE, KILN
- Any of a wide assortment of shelves and posts used in loading a kiln. They are used in supporting
ware to take full advantage of the firing space.
GLAZE
- Finely ground glass, suspended in liquid, applied to ceramic ware to give it a glossy (usually) glass-like surface
when melted by firing.
GREENWARE
- Any unfired clay object.
HIGH FIRE
- Firing to very high temperatures; anything over cone 4. Commonly (cone 6) used with porcelain and stone-
ware.
KILN SITTER
R
- A mechanical device for shutting off the kiln at the desired temperature using pyrometric cones. It is
intended for consistent controlled firing. This device does not always shut off due to operator induced mechanical variables
and must be checked manually.
KILN WASH
- A refractory material used as a coating to prevent sticking of ware and glazes to parts of the kiln and shelves.
It is a powder which is mixed with water and applied with a brush.
LOW FIRE
- Ware fired only to medium temperature as for earthenware, pottery, or terra cotta.
LUSTER
- An overglaze giving an iridescent finish.
MATURITY
- The point at which bisque is completely fired and glazes reach the intended smooth, glassy state.
NESTING
- Stacking one piece of greenware inside another, a technique used in loading for bisque firing.
OHMMETER
- An electrical measuring device for measuring electrical resistance. This is used to check elements for
aging or an open circuit.
OVERGLAZE
- Decorative material applied on top of a glazed surface. Examples are decals, gold and other metallics,
lusters, and china paints. They are always low fired (cone 018 to cone 014)
PEEPHOLE PLUG
- A piece of refractory material used to close the peephole.
PINHOLES
- Imperfections in a glazed surface characterized by tiny holes.
PINS
- Short pieces of high temperature wire used to anchor elements in place.
PORCELAIN
- A type of clay body which becomes vitreous and translucent when high fired.
POST
- Columns of refractory material used to support shelves in the kiln. They are available with square, triangular or
circular cross sections and in many different heights.
PYROMETER
- A high temperature thermometer consisting of a heat sensing device (thermocouple) connected to a meter
readout. Especially important in working with glass. This is an excellent device to measure the progress of a firing and
temperature profile of a kiln.
PYROMETRIC CONE
- A small elongated pyramid of ceramic material which is formulated to soften and deform at a
specific temperature plus time condition, indicating that the ware is mature and the firing complete.
SHELVES
-Slab of refractory material used in the kiln to support ware being fired (see furniture).
SILICA - (SILICAFLOUR, FLINT)
A mineral powder used to prevent sticking of porcelain and other high fire clays
during firing.
SLIP
- Liquid clay used in casting shapes with molds.
