Can you actually throw a Gerstley Borate glaze? Yes!

Tuesday 18th March 2014

G2931 Worthington Clear is a popular low to medium-fire transparent glaze recipe. It contains 55% Gerstley insight-live.com/glossary/129">Borate (GB) plus 30% kaolin (GB melts at a very low temperature). GB is also very plastic, like a clay. I have thrown a pot from this glaze recipe! This explains why high Gerstley Borate glazes often dry so slowly and shrink and crack during drying. When recipes also contain a plastic clay like this one the shrinkage is even worse. GB is also slightly soluble, over time it gels glaze slurries even in smaller percentages. Countless potters struggle with Gerstley Borate recipes.

Pages that reference this post in the Digitalfire Reference Library:

Gerstley Borate, Gillespie Borate, Gerstley Borate 50:30:20 glaze. How could this have worked?, Gerstley Borate vs Frit 3134 melt fluidity comparison, Replacing the Gerstley Borate in recipes containing 50% or more of it, Glaze Gelling, Plasticity

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