Some of the
oxides needed to make glazes have raw material sources that are
not convenient or practical to use. Raw materials can be very soluble
(dissolve readily in water), may not be stable in the atmosphere
or may contain additional oxides not wanted in the glaze. Needed
oxides can be made available in usable form by combining them in
an industrial process called fritting.
is a collection of raw materials (a glaze recipe) which has been
melted to form glass containing the desired oxides. When melted
the mixture is rapidly cooled and ground up into a fine powder ready
to be mixed with other raw materials in the glaze making process.
Frits are often complete glazes in themselves designed for particular
purposes. Mostly, however, they are combined with other raw materials
to make new glazes. They are particularly useful for making low
temperature glazes as commercial versions are designed with low levels of Al2O3 and SiO2..
as feldspars, wollastonite and talc are really naturally occurring
frits created by heat and pressure in the earth's crust.