Plasticity in Ancient and Modern Processing. In the original, ancient technology of ceramics, a mixture of clay and water was found to have the useful characteristic of “plastic flow.” This phrase means that the clay and water mixture can be made to flow into a desired shape by applying a moderate amount of force, for example, by the direct action of human hands. However, when the potter takes his or her hands away from the clay, and only the much smaller force of gravity is then present, the clay will no longer flow. Thus, while the plastic clay-water mixture can readily be shaped by moderate force, it will still keep this shape on the storage shelf until it is fired. Ceramic technology, ancient or modern, is hardly possible without this special capability. When wetted with water, some types of clay such as “ball clay” have better flow properties than others, and these are used for making ceramics where precise shaping is desired. (Note: many of these words are defined more completely in Appendix I.)
KeywordsClay Surfactant Starch Mold Toluene
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- 1.K. K. Chan and D. J. Shanefield, Am. Ceram. Soc. Bul., 68 (1989) 854.Google Scholar