List of pottery terms

From Wikipedia, the free encyclopedia

List of Pottery terms in use (with links to Wiktionary noted as "W" for more information):

• Ball clay. A secondary clay. Ball clays commonly exhibit high plasticity and high dry strength. Organic matter is frequently present. (W)

• Bat. (W)

• Biscuit. or bisque. Pottery that has been fired but not yet glazed. (W)

• Bloating. The permanent swelling of a ceramic article during firing caused by the evolution of gases. (W)

• Blunging. The wet process of blending, or suspending ceramic raw materials in liquid by agitation. (W)

• Body. The structural portion of a ceramic article, or the material or mixture from which it is made. (W)

• Bone Ash. Strongly calcined animal bone. (W)

• Bone china. Vitreous, translucent pottery made from a body of the following approximate composition: 45-50% calcined bone, 20-25% kaolin. 25-30% china stone. (W)

• Candling (W)

• Casting, slip casting (W)

• Ceramic (W)

• China (W)

• Chamotte. A ceramic material formed by the high temperature firing of a refractory clay, after which it is crushed and graded to size. Used as the a non-plastic component of some clay bodies. (W)

• Clay. A group of hydrous aluminium phyllosilicate minerals. Often also used to refer to the clay body, which sometimes may only contain small amounts of true clay minerals. (W)

• Clay body. The material used to form the body of a piece of pottery. Thus a potter might order such an amount of earthenware body, stoneware body or porcelain body from a supplier of ceramic materials. (W)

• Cone, pyrometric cone. (W)

• Crawling. A parting and contraction of the glaze on the surface of ceramic ware during drying or firing, resulting in unglazed areas bordered by coalesced glaze. (W)

• Crazing. A glaze fault characterised by the cracking of fired glazes and due to high tensile stresses. (W)

• Crock. synonym of pot. (W)

• Crocker. synonym of potter (archaic). (W)

• Crockery. synonym of pottery. (W)

• Deairing. The removal of entrapped air from a mass or slurry, often by the application of a vacuum. (W)

• Deflocculate. To separate agglomerates in a slurry by chemical means, and so decrease viscosity. (W)

• Dunt. A crack caused by thermal shock, especially if ware cooled too rapidly after it has been fired. (W)

• Earthenware (W)

• Enamel (W)

• Eutectic. An invariant point on an equilibrium diagram. A mixture of two substances which has the lowest melting point in the whole series of possible compositions. (W)

• Engobe. A slip coating applied to a ceramic body for imparting colour, opacity or other characteristics. It may subsequently be covered with a glaze. (W)

• Faience (W)

• Fettling. The removal, in the unfired state of excess body left in the shaping of pottery-ware at such places as seams and edges. (W)

• Flatware (W)

• Flux. A substance that promotes fusion in a given mixture of raw materials. (W)

• Frit. A product made by quenching and breaking up a glass of a specific composition. Common uses include as components of a glaze or enamel. (W)

• Glaze. A coating that has been matured to the glassy state on a formed ceramic article, or the material or mixture from which the coating is made. (W)

• Grog. See chamotte. (W)

• Hollowware. (W)

• Jigger. A machine for the shaping of clay body into flatware by the differential rotation of a profile tool and mould. Also the process. (W)

• Jolley. To shape hollowware by the same process as jigger. (W)

• Leather-hard The condition of a clay or clay body when it has been partially dried to the point where all shrinkage has been completed. (W)

• Maturity. The combined effects of firing time and firing temperature on ceramic wares in a kiln. Within limits, wares fired at low temperatures for extended periods may develop a degree of maturity similar to that achieved by applying higher firing temperatures for shorter periods. (W)

• Modulus of Rupture. The maximum transverse breaking stress applied under specified conditions, that a material will withstand before fracture. It is used as a common quality control test used for both ceramic rawmaterials and ceramic bodies. (W)

• Once-fired, green-fired (W)

• Overglaze (W)

• Oxidation (W)

• Pinholes. Faults in the surface of a ceramic body or glaze which resemble pin pricks. (W)

• Porcelain. A vitreous ceramic material. Traditionally considered to be white and, if of thin section, translucent. (W)

• Pottery. All fired ceramic wares or materials which, when shaped, contain a significant amount of clay. Exceptions are those used for technical, structural or refractory applications. Pottery is also: (1) the ware made by potters; (2) a ceramic material (3) a place where pottery wares are made; and (4) the business of the potter. (W)

Published definitions include:

-- "All fired ceramic wares that contain clay when formed, except technical, structural, and refractory products."^[1]

-- "China, earthenware and any article made from clay or from a mixture containing clay and other materials."^[2]

-- "A class of ceramic artifacts in which clay is formed into containers by hand or in molds or with a potter's wheel, often decorated, and fired"^[3]

-- "The term pottery includes many varieties of ware from the crudest vessels of prehistoric times to the most beautiful decorated porcelains, stoneware and earthenware; it also includes many articles such as large grain-jars used in ancient times for storing corn and other dry materials, wine-jars and modern sanitaryware and the large tanks for containing corrosive acids. Many kinds of earthenware, stoneware and porcelains are used for scientific and experimental purposes as well as electrical apparatus (insulators, switch-bases, sparking plugs and bases or frames for electrical heating appliances)."^[4]

• Pug. A machine for consolidating plastic clay or body into a firm column. It consists of a barrel which tapers at one end to a die, through which the clay or body is forced by knives mounted on a shaft which rotates centrally to the barrel. A vacuum system may be installed to de-ier the clay or clay body. (W)

• Roller-head machine(W)

• Saggar. A lidded or covered ceramic box used to protect wares from direct flame, smoke, fuel-ash or cinders during firing.(W)

• Slip A suspension of clay, clay body or glaze in water.(W)

• Soaking(W)

• Stoneware. A vitreous or semivitreous ceramic material. Traditionally made primarily from nonrefractory fire clay.(W)

• Terracotta (W)

• Underglaze (W)

• Water Absorption. The mass of water absorbed by a porous ceramic material, under specified conditions, expressed as a percentage of the mass of the dry material. It is used as a common quality control test used for both ceramic raw materials and ceramic bodies. (W)

• Wedging. A procedure for preparing clay or a clay body by hand: the lump of clay is repeatedly thrown down on a work bench; between each operation the lump is turned and sometimes cut through and rejoined in a different orientation. The object is to disperse the water more uniformly, to remove lamination and to remove air. (W)

[edit] References

1. ^ American ASTM Standard C 242-01 Standard Terminology of Ceramic Whitewares and Related Products.
2. ^ COSHH in the Production of Pottery, Approved Code of Practice. HM Stationery Office 1990.
3. ^ Ashmore and Sharer 2000:252.
4. ^ The Chemistry and Physics of Clays. 3rd edition. A.Searle & R.W.Grimshaw. Ernest Benn. 1959.

• ASTM Standard C242-00. Standard Terminology of Ceramic Whitewares and Related Products.
• Dictionary of Ceramics 3rd edition. Dodd A., Murfin D. The Instiutue of Materials. 1994.