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cracking teapots and thermal expansion

updated fri 31 jan 97


R Wuetherick on thu 23 jan 97

If you look back in "Ceramics Monthly" there was an excellent article
on using spodumene in clay bodies to increase resistance to thermal
shock. The author claims that one of the bodies tested was raku'ed
and it was waterproof. So maybe you might want to take a look
at this article..

Has anyone on this list tried any of those bodies or done any
in this direction.

Rod Wuetherick

> snip
> To increase the thermal shock resistance the body must be altered
> eliminate or reduce cristobalite formation.This is usually done by
> addition of Feldspar to convert the cristobalite to a low expansion
> silica glass,the addition of flint to adjust the expansion if
> and a possible clay adjustment to see that the body does not over
> vitrify.
> Regards
> Roger Keane
> Keane Ceramics Pty Ltd
> Somersby N.S.W.
> Australia.