CaO is a strong flux but it can cause crazing

Saturday 13th April 2013

2, 5, 10, 15% insight-live.com/material/173">calcium carbonate added to Ravenscrag Slip on a buff stoneware fired at cone 10R. It gets progressively glossier toward 15%, crazing starts at 10% (test by Kat Valenzuela). Adding a flux only reduces the SiO2 and Al2O3, this pushes the thermal expansion upwards. 5% is actually sufficient. An alternative would be to use wollastonite, it supplies SiO2 also.

Pages that reference this post in the Digitalfire Reference Library:

Calcium Carbonate, CaO, GR10-A - Pure Ravenscrag Slip, The unexpected reason for this crazing can be seen in the chemistry

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