Why does this glaze look like this? What are its mechanisms?

Tuesday 8th June 2010

This is cone 6 an oxidation transparent glaze having enough flux (from a boron frit or Gerstley Borate) to make it melt very well, that is why it is running. Iron oxide has been added (around 5%) producing this transparent amber effect. Darker coloration occurs where the glaze has run thicker. These are all simple mechanisms, which, once understood, can be transplanted into other glazes. This glaze is also crazing. This commonly occurs when the flux used is high in K2O and Na2O (the highest expansion fluxing oxides). K2O and Na2O produce the brilliant gloss. They come from feldspars, nepheline syenite and are high in certain frits.

Pages that reference this post in the Digitalfire Reference Database:

Iron Oxide Red, Reducing the Firing Temperature of a Glaze From Cone 10 to 6, Glaze Recipes, Mechanism

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.