What's the maximum firing temperature for your clay bodies?
This is approximately indicated by the vitrification point stated for each clay in our catalogue but, with stoneware, it will be lowered by reduction firing conditions and is dependent upon other factors such as firing cycle. Consequently this figure is given only as a guide for comparison purposes. If clays are fired above their vitrification point then bloating is likely. Bloating may also result from insufficient biscuit firing or too fast firing in the later stages of the glost firing. Conversely, overlong firings may give excess heat work and cause bloating.