Studying Studying Ceramics Ceramics

VocabularyVocabulary

AIR POCKETS

Air which is trapped inside the body of the clay. This expands and can create explosion in the kiln. Wedging clay before use is a good way to avoid this problem.

BASE

A slab or platform on which clay is handled; a circular device attached to the wheel-head.

BISQUE

Unglazed clay, fired once at a low temperature. Ceramic piece will not blow up in firing.

BISQUE FIRING

The first firing of unglazed ware; this removes all moisture from the clay and prepares it for further steps like glazing. The approximate temperature of this firing is 1815 F.

BONE DRY

The condition of unfired clay when it is as dry as possible prior to firing.

CENTERING

The act of aligning the clay on the potter’s wheel in order to proceed with forming and shaping.

CERAMICS

The art of making things of clay. Clay is an ancient tradition.

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.

CLAY BODY

A mixture of clay and other materials selected to produce particular characteristics to meet the ceramist’s needs.

COIL

A long roll of clay.

COIL CONSTRUCTIO

N

Rope like pieces of clay that are stacked to form a wall and build the object. This technique is one of the most commonly used hand-building methods. The size of the coils can vary but must be slipped and scored into place or one side in blended to create strength.

FIRE

To bake in a kiln. Firing is a term used for “cooking” the clay.

FOOT

A slightly raised area or ring on the bottom of a pot.

FORM

Three-dimensional shape and structure of an object.

GLAZE

A compound of materials that is applied to the surface of greenware or bisqued ware and that forms a glassy coating when fired.

GLAZE FIRE

Much hotter than a bisque fire. Firing to a temperature at which glaze melts to form a glasslike surface.

GLAZE FIRING

Typically the second firing that reaches temperatures at which glazes will melt. The approximate temperature of this firing 2300.

GLOSS

A shiny surface.

GREENWARE

Pottery that has not fired. It is bone-dry, a state in which clay forms are the most fragile.

GROG

Ground fired clay that is added to a clay body to reduce shrinkage and warping.

HANDBUILDING

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

INCISING

Indenting a line into a flat surface.

KILN

A furnace built for firing ceramic ware. It is built of refractor brick & heated by electricity, gas, oil or wood to temperatures from 1500 F to 2340 F.

KILN FURNITURE

Pillars and stilts which hold pieces during the 2nd firing. Shelves to make various levels within the kiln.

LEATHER HARD

The condition of a clay body that has dried somewhat but can still be carved or joined. Hard to bend & soft enough to be carved.

MATTE

Not shiny.

OVERGLAZE

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

PLASTIC

The stage in which clay is soft, pliable, and moldable, versus dry and brittle.

POTTERY

Pottery was one of the first art forms explored by mankind. There are many extinct cultures throughout the world who did not leave behind any written record of their existence. For some of these civilizations the only evidence of their daily lives comes in the form of pottery. Some pots were for daily use and some were for ceremonial purposes. Some cultures buried their pots with their dead, and some had huge garbage dumps where broken pots ended up. Pottery and other forms of ceramics have left behind an important archaeological record.

PYROMETRIC CONES

Pyrometric Cones are designed to melt or bend after reaching a specific temperature (depending on the rate of rise). The original large sized pyrometric cones are used in a cone holder on the kiln shelf for visual firing, testing or monitoring of the temperature in the kiln. Small Cones are used where space is at a premium.

SCORING

Roughing up of the surface of clay for joining two pieces together.

SLAB

Clay which has been made flat by using a rolling pin.

SLAB CONSTRUCTIO

N

Handbuilding technique in which flat pieces of clay are joined (clay is flattened and thinned with a rolling pin or slab roller joined by slipping and scoring pieces together.

SLIP

A mixture of clay and water. It is the glue that adheres to pieces of “plastic” clay.

TERRA COTTA

“baked earth” ( a red, low-fired clay)

THROWING

Forming clay on a potters wheel.

UNDERGLAZE

colored decoration applied to bisque clay, then coated with a clear glaze. Typically made of clay slip and raw pigment.

WEDGING

Kneading clay by cutting and reforming it in order to expel air.