Clay Bodies

摘要

FIRING RANGE This is a fundamental choice and will determine not only which clay, but also the colours, glazes and bisque and glaze firing temperatures. A completely different set of glazes will be needed for firing raku (1,000-1,060 deg C), earthenware (1,040-1,160 deg C), or stoneware (1,200-1,300 deg C). Stoneware and porcelain can, however, utilise the same glazes and firing cycle. CLAY COLOUR This is relevant to the look and style of the work and will have some influence on the apparent colour of any glaze. For example, the test files in image 10 show the same transparent honey glaze over nine different clays fired in an electric kiln, although this effect would be less noticeable with opaque glazes. In practice, the earthenware clays come down to a choice of red or white. For stoneware the choice is buff or white although there are a few red clays that can just about tolerate being fired to the low end of the stoneware range. For porcelain the only choice is white.