Monthly Tech-Tip | No tracking! No ads! |
In the new recipe I am trying to match the oxides (the white, yellow, red, blue boxes). B2O3 is priority, I have supplied enough of the new frit to almost match it, but that far overshoots the Na2O (even if all of the feldspar is removed). While differences in the Al2O3 and SiO2 can be compensated by adjustments in the feldspar, clay and silica, the new frit has far more Na2O and only half the B2O3. The match shown here is the best I am able to achieve, its biggest problem is the significant rise in the calculated thermal expansion, that is going to mean issues with crazing. The only way to use this frit to better match the chemistry of the original glaze would be in combination with another one that has much higher B2O3 and has as little Na2O as possible.
You will see examples of replacing unavailable materials (especially frits), fixing various issues (e.g. running, crazing, settling), making them melt more, adjusting matteness, etc. Insight-Live has an extensive help system (the round blue icon on the left) that also deals with fixing real-world problems and understanding glazes and clay bodies.
Glossary |
Glaze Chemistry
Glaze chemistry is the study of how the oxide chemistry of glazes relate to the way they fire. It accounts for color, surface, hardness, texture, melting temperature, thermal expansion, etc. |
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