Generic Base Crystalline Glaze
Recipe
Notes
From Crystal Glazes Book 1 by Fara Shimbo, page 37. Almost all other recipes are based on additions to this. The more frit you use (relative to the other ingredients), the lower will be the maturing point. That being said, almost all of the recipes here have close to 50% of this frit. The more silica, the less the glaze will tend to craze, but the fewer the crystals produced. Zinc silicate is Zn2SiO4, so for every molecule of ZnO, two SiO2s are needed to form the crystals. Of course the crystals are on the surface and make up only a small part of the total glaze volume, that leaves extra SiO2 for the glaze itself. In this recipe the SiO2:ZnO ratio is 2.5:1. Understandably, raising and lowering the amount of zinc oxide will directly affect how many crystals the glaze will be able to grow. That being said, almost all recipes here have 25% zinc. The recipes here add small amounts, usually 5-10%, of other materials, usually at the expense of the silica. The most common addition is titanium dioxide. MgO is added using dolomite, talc or magnesium carbonate. Li2O is sourced from spodumene and lithium carbonate. CaO from whiting or dolomite. Tin oxide is also used. These additives affect opacity; crystal size, shape and ancillary development; and color. In a couple of instances, other frits are also used. There is much more background information in Crystal Glazes books 1 and 2 (specifically about this in book 1 page 37).
Description
Cone 6-10 - Almost all other Frit 3110 recipes are based on additions to this