Glazes
A glaze is a glass-like substance applied in the form of a layer of powder, fused into place
on a pottery body to give it waterproof qualities
It is basically composed of glass-forming oxides or acids (like silica, feldspar or quartz), fluxes
or alkaline oxides (like soda, potash, calcium and lead) and stabilizers or neutrals (like alumina).
All the oxides in the glaze are solids, but the alkali-acids interaction when exposed to heat
results in the formation of a liquid, with the neutrals helping rebalancing it to a perfect fusion.
When fused, the glaze interacts with the body; in earthenware only in a superficial way,
but in stoneware, glaze and body become one.
Various oxides can be used to make glazes in endless colour and texture combinations.
For Example Copper oxide produces greens and blues in oxidising atmosphere,
and reds in reduction atmosphere, cobalt oxide and carbonate produces blues and Iron
oxide browns and oranges. Tin works as an opacifier to turn glazes white.