Posted 28 May 2013 - 04:56 PM
I'm thinking that maybe your clay doesn't have an open enough body, that is, it would be less prone to warping and cracking if it contained more coarse material such as sand or grog (ground up fired clay). That would improve the evenness of drying and other workability characteristics. It wouldn't have to be super coarse. It's true that firing temperature of the clay wouldn't be the issue, but I think there might be more variety in clays you could try among those that fire to ^5-6 or higher. You don't want it to mature at a much higher temp than you are planning to fire it to. A lot of ^5-6 clays contain fine to medium sand and are nice to work with without the coarseness being noticeable. Or you could get one with a noticeably coarse body if you like the feel and look of that. I'm not really very familiar with low-fire clays, around ^05 or ^06, but get the feeling many of them don't contain much coarse material. I could be wrong about that. Perhaps your clay supplier could help you with this.