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Clayworks Vocabulary List: Absorbency – The ability of a material to soak up water Ball Clay - An extremely fine-grained plastic and sedimentary clay. Bat – A disk on which pottery is formed or dried; it is also used to remove excess water from plastic clay. Bisque or biscuit - Unglazed ware fired to a temperature sufficient to harden but not mature the body. Clay - A decomposed granite-type rock; To be classed as aclay the decomposed rock must have fine particles so that it will be plastic. Coiling - A hand method of forming pottery by building up the walls with rope-like coils of clay and then smoothing over the joints. Crackle glaze - A glaze containing minute cracks in the surface caused in cooling by the different rates at which the body and the glaze contract after firing. Crawling - The separation of the glaze coating from the clay body during the firing caused by too heavy application. This results in exposed areas of unglazed clay. Crazing - An undesirable and excessive crackle in the glaze, which penetrates through the glaze to the clay body. Dipping - Glazing pottery by immersing it in a large pan or vat of glaze. Dry foot - To clean the bottom of a glazed piece before firing. Dunting - Cracking of fired ware in a cooling kiln as a result of opening the flues and cooling too rapidly. Earthenware - Low-fire pottery. (porous) Engobe - A prepared slip that is halfway between a glaze and a clay; usually applied to damp ware although may be used on bisque ware. Flux - Lowest melting compound in a glaze such as lead , borax , soda ash, or lime, and including the potash or soda contained in the feldspar; the flux combines easily with the silica and thereby helps higher melting alumina-silica compounds to form a glaze. Foot - The ring-like base of a ceramic piece, usually formed by tooling the excess clay. Glaze - A liquid suspension of finely ground materials that is applied by brushing, pouring, or spraying on the surface bisque-fired ware. Glaze ingredients will melt together to form a glassy surface coating. Glaze Fire - A firing cycle to the temperature at which the glaze materials will melt together to form a glasslike surface coating. Greenware - Pottery that has not been bisque fired. Grog - Hard fired clay that has been crushed or ground to various particle sizes. It is used to reduce shrinking in such ceramic products such as sculpture and architectural terra cotta tiles, which have drying or shrinkage problems. Finely crushed grog is also used in throwing bodies to help the clay stand. Kaolin - Pure clay-also known as China clay. It is used in glass and porcelain bodies and fires to a pure white. Kiln - A furnace/oven made of refractory clay materials or firing ceramic products. Kiln furniture - Refractory shelves upon which the clay work is placed within the kiln to be fired. Leather hard - The condition of the raw ware when most of the moisturehas left the body but when it is still plastic enough to be joined or carved. Mat glaze - A dull surface with no gloss but pleasant to the touch. Maturity - The temperature or time at which the clay body develops the desirable characteristics of maximum non-porousity and hardness; or the point ta which the glaze ingredients enter into complete fusion, developing a strong body with the body, a stable structure, maximum resistance to abrasion, and a pleasant surface texture. Overglaze - Decoration applied with overglaze. (Usually shiny in appearance) as opposed to underglaze which is mat and not shiny in appearance. Porcelain(hard) - A hard non-absorbent clay body that is white or gray, that rings when struck. Raku - Glazed, groggy earthenware that originated in Japan and is associated with the tea ceremony. Shard: A broken fragment of pottery Short - A term describing a body of clay that is lacking in plasticity. Single fire - A firing cycle in which the normal bisque and glaze firing\s are combined Slab construction - A hand building method in which forms are created by joining flat pieces of clay. The pieces are thinned and flattened with a rolling pin or slab roller. Slip - The mixture of clay and water. This is used to join leather hard clay bodies together and for slip trail decoration. Stain – Sometimes a single coloring oxide , but usually a combination of oxides plus alumina, flint and a fluxing compound. The purpose is to form a stable coloring agent not likely to be altered by the action of the glaze or heat. Stoneware – A high-fire ware with slight or no absorbency. It is uasually gray in color but may be tan. Terra-cotta – An earthenware body generally red in color and containing grog. It is the common body type used in ceramic sculpture. Throwing – Forming plastic cly ona potter’s wheel. Turning or tooling – Trimming the walls and foot of a poton the wheel while the clay is leather hard. Wax resist – A method of decorating pottery by brushing on a design with a solution of wax. This will prevent an applied stain or glaze from adhering to the decorated portions. *The three most common techniques used in ceramics are: Pinch, Slab building, throwing on the wheel, and coil.
"Absorbency – The ability of a material to soak up water"