The green underglaze bond is failing on impact
Tuesday 23rd August 2016
This is a insight-live.com/glossary/43">fritted stoneware fired to cone 03. There is plenty of glass development to form a strong interface with glazes and underglazes. But this green commercial underglaze is not bonding well with the body. Repeated blows to the surface by a hammer (insufficient to break the piece but enough to test the glaze) are chipping off chunks of glaze/underglaze at the latter's interface with the body. This does happen with most other underglazes tested. The green underglaze is obviously more refractory and should be reformulated so that its stain medium develops enough fired maturity to counteract the refractory stain.
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