What would happen if you made a clay body from 50:50 kaolin and ball clay?

Saturday 18th April 2015

It would insight-live.com/trouble/2">craze glazes! Really badly (this is fired at cone 6). One might think that there is adequate quartz in this high of a percentage of ball clay to at least minimize crazing, even causing shivering. At cone 10 oxidation this has about 5% porosity (the ball clay contributes enough iron that porosity drops to 2% in reduction). While an addition of feldspar would cut this somewhat, only more silica will increase thermal expansion enough to put the squeeze on glazes to prevent crazing like this.

Pages that reference this post in the Digitalfire Reference Library:

Silica, Ball Clay, Cristobalite Inversion, Quartz Inversion

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