Ferro Frit 3110

Soft sodium borosilicate frit for glazes. Often used in crystal glazes.This frit can be very useful to reduce the feldspar content in glazes (since many high feldspar glazes have low clay content and therefore poor slurry suspension properties and dried hardness). The chemistry of this frit is similar to a feldspar (but with low alumina and CaO in addition to the alkali fluxes). That means if you can substitute this for at least part of the feldspar you can increase the kaolin (to supply the alumina) and thereby improve slurry properties. In addition you will be able to reduce the amount of troublesome calcium carbonate. Of course, you need to use ceramic chemistry to calculate how to do this. (DigitalFire)

Na2O 15.3% Al2O3 3.7% SiO2 69.8%
K2O 2.3% B2O3 2.6%
CaO 6.3%

Expansion: 104.2 x 10e-7 per degree C
Oxides causing abnormal expansion:
B2O3

Na2O 0.64 Al2O3 0.09 SiO2 3.03
K2O 0.06 B2O3 0.10
CaO 0.29

Alumina:Silica ratio is 1.00:32.01
Neutral:Acid ratio is 1.00:15.78
Alk:Neut:Acid ratio is 1.00:0.19:3.03

Melting range 920-950 C
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Ferro Frit 3134

This is a popular frit and has been used for many years as a general purpose melter across all tempreatures. Equivalents are made by many frit companies. The manufacturer says that it is "intended for use as a lime and borate source in partially fritted glazes, lead bisilicate glazes and low cost hobby glazes cone 06-10". Not many frits have higher boron than this one, so this is considered an excellent source where boron is required. Since this frit has no alumina adding it to a recipe does not require reduction of clay content to reduce alumina. These reasons are likely why it is billed as useful from 06-10 (although boron is uncommon in high fire glazes).(Digitalfire)

Na2O 10.3% B2O3 23.1% SiO2 46.5%
CaO 20.1%

Na2O 0.32 B2O3 0.63 SiO2 1.48
CaO 0.68

Expansion: 93.4 x 10e-7 per degree C
Oxides causing abnormal expansion:
B2O3

Melting point 790 C