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Ceramic Clays

Our clays are accurately formulated, completely mixed and ready for immediate use or long storage. We offer both earthenware and stoneware clays. We strongly recommend testing the clays using your particular working process, glazes and firing procedures before beginning any important projects.

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Clay in moist form is considered non-toxic. Silica, which is present in all ceramic clays, has been linked to the possibilities of environmental health problems which may occur through long term respiratory exposure to the dust in dry clay. Avoid dust producing procedures (dry mixing, sanding). Keep clays moist. Be sure your work area is well ventilated. Wash or damp mop floors and tables. Brushing up or sweeping will raise dusts.

Clay used for pottery is indigenous to only certain regions of the world and every manufacturer uses the same base clay. United States clay body formulas are generally a mixture of several different types of clay, derived primarily from clays mined in Georgia, Tennessee, Ohio. Small amounts of darker clays that make up a formula, such as Van Dyke Brown, are found in New Mexico. Clay mined in California has a gritty coarse texture and therefore, is not usually used in formulas. Fine grogless clays from England are used for making porcelain clay bodies.

The earthenware clays generally vitrify at a lower temperature than the stoneware or porcelain clays. (Vitrification is the process whereby a clay body is heated until it becomes non-porous.) Stoneware clays fire to a higher temperature and is, therefore, a harder material than earthenware.

There are two types of firing: bisque firing and glaze firing, both done in kilns at temperatures ranging from cone 014 to cone 10. Bisque firing is the initial of first firing of a dried piece of pottery or ceramic, also known as greenware, performed before glaze firing. Glaze firing is the second firing; glaze is a colored liquid material that can be matte, gloss, or speckled. It is a silica that when heated fuses together and forms a glass-like coating.