Two matte mechanisms: One crazes the other does not


Monday 12th February 2018

These two glazes look the same, they are both cone 6 satin mattes. On the same insight-live.com/glossary/71">porcelain. But the matteness "mechanism" of the one on the left, VC71, is a low Si:Al ratio melted by zinc and sodium. The mechanism of the one on the right, G2934, is high MgO melted by enough boron to also have plenty of SiO2 and Al2O3. The "baggage" of the mechanism on the left is high thermal expansion and crazing (drastically reducing strength and providing a space for a germ zoo). If your ware develops this your customers will bring it back for replacement. No change in firing will fix this, the body and glaze are not expansion compatible. Period.

Pages that reference this post in the Digitalfire Reference Library:

This is crazing. Crazing is bad on functional ware., Why does VC71 not cutlery mark when it is barely melting?, Is the V.C. 71 pottery glaze a true matte? , Co-efficient of Thermal Expansion, Calculated Thermal Expansion, Glaze Crazing


This post is one of thousands found in the Digitalfire Reference Database. Most are part of a timeline maintained by Tony Hansen. You can search that timeline on the home page of digitalfire.com.