The need to get better transparency in G1947U was the motivation I needed to try frits at cone 10R. I did it by doing some glaze chemistry. Sound boring? Yes. Until you see the results.
This screenshot of side-by-side panels in my account at Insight-live.com shows the original G1947U beside the frit-enhanced version, G3910. It employs frit 3110 as a higher-concentration source of KNaO. The extra KNaO adds brilliance to the glass like no other oxide can, but also increases the COE. The extra melting the frit brought gave me a great countermeasure: I added frit 3249 to introduce some low-expansion MgO. That supercharged melting by bringing more boron, enabling another enhancement: The ability to dissolve more glass-forming SiO2 in the melt.
One more change: I have introduced calcined kaolin (to ratio with the raw kaolin to control slurry and drying properties).

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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.

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I calculated a frit-based recipe to match the original G1947U Cone 10R clear feldspar-based one. Only after seeing the fired results did I fully realize how much better it melts and how much more transparent it fires.
My original approach was just theoretical: Shift KNaO-sourcing from feldspar to frit to get a better melt. As calculations took shape, it became clear that I could increase KNaO (it is a super-flux for cone 10 brilliant surfaces). Those options would theoretically supercharge melting more, enabling dissolving additional SiO2 (which would improve durability). When the kiln opened, I got a surprise with the original G1947U: It never looked white when firing on the ware, but when seeing it thick like on this GBMF test (bottom), it looks really cloudy. Likely the melt is not completely dissolving the particles of quartz! The surface brilliance of the new G3910 blew me away at first; it really is better (top right is G1947U left, G3910 right on buff and brown bodies). There are unexpected benefits: This glaze develops a better interface with the body. And on porcelains, it is more crystal clear and much brighter.
| Typecodes |
Glaze Chemistry
Case studies where glaze chemistry was used to solve a problem. |
| Materials |
Ferro Frit 3249
A magnesia borosilicate frit. Very low thermal expansion and melting point. Invaluable in pottery to increase the MgO in glazes and thereby prevent crazing. |
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