Ferro Frit 3134
This is a popular frit and has been used for many years. Equivalents are made by many frit companies. Recommended for use as a lime and borate source in partially fritted glazes and low cost hobby glazes cone 06-10.
Several factors make this frit's chemistry so attractive:
-It has almost no alumina. That means, as already stated, that Al2O3 can be supplied by clay, giving the glaze better suspension and hardening properties. Conversely, adding Frit 3134 to a recipe (to supply boron for example) does not require reduction of clay content.
-It has high sodium. That means that it's presence enables reducing feldspar content which in turn provides even more opportunity to source Al2O3 from kaolin or clay.
-It has high boron. That gives it a lot of bang-for-buck as a flux, especially in middle temperature.
-It has a very high CaO content. That makes it useful for developing chrome-tin pinks and maroons. CaO-sourcing raw materials do not normally melt at low temperatures but a frit of this chemistry (high soda and boron) does.
Leadless and low alumina high calcia borosilicate frit
Frit Melting Range: 1450 - 1600F