Frits melt so much better than raw materials

Friday 1st August 2014

insight-live.com/material/310">Feldspar and talc are both flux sources (glaze melters), they are common in all types of stoneware glazes. But their fluxing oxides, Na2O and MgO, are locked in crystal structures that neither melt early or supply other oxides with which they like to interact. The pure feldspar is only beginning to soften at cone 6. Yet the soda frit is already very active at cone 06! As high as cone 6, talc (the best source of MgO) shows no signs of melting activity at all. But a high-MgO frit is melting beautifully at cone 06! The frits progressively soften, starting from low temperatures, both because they have been premelted and have significant boron content. In both, the Na2O and MgO are free to impose themselves as fluxes, actively participating in the softening process.

Pages that reference this post in the Digitalfire Reference Library:

Frit, Ferro Frit 3110, Talc, B2O3, Na2O, MgO, Melting Temperature, Oxide Interaction, Frit, Feldspar Glazes, Flux

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.