|Monthly Tech-Tip |
Look at recipes before wasting time and money on them. Are they serious? This is a cone 6 GLFL test to compare melt-flow between a matte recipe, found online at a respected website, and a well-fluxed glossy glaze we use often. Yes, it is matte. But why? Because it is not melted! Matte glazes used on functional surfaces need to melt well, they should flow like a glossy glaze. How does that happen? This recipe has 40% nepheline syenite. Plus lots of dolomite and calcium carbonate. These are powerful fluxes, but at cone 10, not cone 6! To melt a cone 6 glaze boron, zinc or lithia are needed. Boron is by far the most common and best general purpose melter for potters (it comes in frits and gerstley borate, colemanite). Other melters used less often are zinc and lithium (or the fritted forms). The lesson: Look at recipes before trying them, we use the term limit recipe to describe the skill of being able to eye-ball a recipe and quickly assess if it is ridiculous or not.
Stop! Think! Do not get addicted to the trafficking in online glaze recipes. Learn how they work. Understand them. Then make your own or adjust/adapt what you find online.
Random material mixes that melt well overwhelmingly want to be glossy, creating a matte glaze that is also functional is not an easy task.
This term refers to critical thinking ability that potters and technicians can develop to recognize recipes having obvious issues and merit, simply by seeing the materials and percentages.
A Textbook Cone 6 Matte Glaze With Problems
Glazes must be completely melted to be functional, hard and strong. Many are not. This compares two glazes to make the difference clear.
|Oxides||B2O3 - Boric Oxide|