September 08, 2011

Bottled Project Update

Casting and Testing

To distinguish the Bottled Project from other rcboisjoli projects we've been designing a new glaze for the series. Creating a stain matte white glaze has been our goal, with dozens of recipes online and in books, there's no shortage of ideas around. We however, use a base list of materials for all our glazes. It simplifies ordering and cost for materials too. If all our glazes are based on the same ingredients, we have to order fewer bags of dry goods and larger cheaper quantities of our base materials. 

This run has been seven edits along the line to create a solid, stain matte, white glaze. Glazes are a careful mix of melters (fluxes) stabilizers (alumina) and glass makers (silica). We prefer a boron based glaze with lots of nyepheline syenite. Plenty of calcium and zinc help the create a matte glaze, as does a commercial opacifier, like Ultrox.

After a week of testing, we're going to run with glaze 090911 the last in our series of tests. It's solid, matte, white and food safe too. It should take the decal well, which is important for this project! Always test and retest glazes. It may seem like a lot of work to do, but it's amazing to find a glaze that just works well for you.
We always save off-casts from the bottle runs to save for glaze tests. Usually it's the ones that we forget to time in the molds and end too heavy and thick to use.

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