- Glass-former (not a flux), though it has a molecular structure similar to alumina
- Major exception to neat structure of Seger UMF
- Has melting point of 1992°F but starts melting at 572°F
- Forms glass at a low temperature, lowering the melting point of the whole glaze — it’s a glass former, not a flux, and is tracked separately from the fluxes in the unity formula
- Cone 10 glazes containing it start to melt very early but it also volatilizes over 2102°F
- Produces good color response in glazes
- Characteristics include Bluish, milky streaks and cloudy effect
- Copper red glazes and brightly colored glazes, from 5-15%, at cone 10
- Low expansion and contraction rate
- aids in reducing crazing
- if more than 10% in glaze loses elasticity and ant-crazing effect may be reversed
- Low viscosity and surface tension
- glazes containing boron will be smooth and glossy
- may even run onto the shelf it applied too heavily
- Element has no known toxicity but is soluble
- Soluble sources include Gerstley Borate (and subs), colemanite, ulexite, borax, and boric acid
- Insoluble sources are Frits, which are slightly soluble.
