Glossary

Practical definitions of ceramic terms

Ball clay:  a very plastic high-firing clay.  It is not really used as a clay body in itself.  Rather it is added to other types of clay to enhance their performance, because of its plastic feature.

Ceramic glaze:  a mixture of powdered materials that often includes a premelted glass made into a slip and applied to a ceramic body by spraying or dipping and capable of fusing to glassy coating when dried and fired.

Clay: a natural earthy material, composed mainly of fine particles of hydrous aluminum silicates and other minerals, that can be moulded when wet, and is dried and baked to make bricks, pottery, and ceramics. There are 5 main types of clay: earthenware, stoneware, porcelain, ball clay, and fire clay.

Clay Slip: a slurry of clay and water used in casting ware.

Decal: a picture or design printed on special paper, that can be put onto another surface, such as metal or ceramics.

Earthenware: ceramic ware made of slightly porous opaque clay fired at low heat. Usually, the earthenware clay is red or Orange and has a more earthier and rustic look.

Fire clay: clay capable of withstanding high temperatures that is used especially for firebrick and crucibles. Like ball clay, fire clay is also used as an additive, and its key function is to raise the temperature firing range of the clay body to which it’s being added.

Glazing:  the process of dipping or spraying the ceramic body with ceramic glaze.

Green body:  is an object whose main constituent is weakly bound clay material, usually in the form of bonded powder or plates before it has been sintered or fired.

“Madre”: “mother of all”. A resistant mould, usually made of  silicone, from which unlimited pieces can be made.

Mould: a material shaped into a certain shape and style.

Moulding: to knead or work a material, such as dough or clay, into a desired consistency or shape.

Plaster: a substance that becomes hard as it dries.

Porcelain: a hard, fine-grained, sonorous, nonporous, and usually translucent and white ceramic ware that consists essentially of kaolin, quartz, and a feldspathic rock and is fired at a high temperature. Porcelain has the capacity to look very delicate and refined but is also tough and non-porous. So, it can be used for detailed sculptural artistic work, but also for dinnerware.

Press machine:  is a machine tool that changes the shape of a work-piece by the application of pressure.

Sintering:  is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction.

Release agent:  a combination of industrial soap and water used to prevent other materials from bonding to surfaces.

Retraction Ratio: a percentage of the clay retracts when in production. On the Roller machine the percentage is 5%, and in slip casting is 8%.

Roller machine: is used to compress ceramic materials, giving it his intended shape.

Slip casting: the process of forming ceramic ware by pouring slip into, usually, plaster molds.

Stoneware: a strong opaque ceramic ware that is high-fired, well vitrified, and nonporous. Stoneware clay comes in different colors, but it’s often grey when it is moist. Because stoneware is tough and quite non-porous, it’s often used by commercial manufacturers to make dinnerware and vases.

Turning lathe: a device or machine for throwing and turning pottery, consisting of a frame and a revolving horizontal disc on which the clay is placed.

Scroll to Top