An example where adding silica really helps a glaze

Thursday 20th February 2014

The flow on the left is an adjusted Perkins Frit Clear (we substituted frit for Gerstley Borate). It is a cone 6 transparent that appeared to work well. However it did not survive a 300F oven-to-icewater IWCT test without crazing on Plainsman M370. The amount of flow (which increases a little in the frit version) indicates that it is plenty fluid enough to accept some silica. So we added 10% (that is the flow on the right). Now it survives the thermal shock test and still fires absolutely crystal clear.

Pages that reference this post in the Digitalfire Reference Database:

MgO, SiO2, G2926B - Cone 6 Whiteware/Porcelain Transparent Base Glaze, Find and Improve a Cone 6 Clear Ceramic Glaze

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