Opax Glaze Opacifier Zicronium oxide Pottery supplies 1 lb. Zicron Ultrox

Description

You are buying 1 pound of Opax Zicronium Oxide powder to opacify clear glazes.
Other Opacifiers are Ultrox Zicron, Tin Oxide etc.
Opax is a brand name for Zirconium oxide opacifier.  This will increase the viscosity of the glaze.  It also can be used to make matt glazes.  This makes a very hard glaze.
Opax
Oxide
Analysis
Formula
Na2O
1.11%
1.00
ZrO2
90.84%
41.18
Al2O3
0.91%
0.50
SiO2
6.48%
6.02
Oxide Weight
5,548.72
Formula Weight
5,548.72
There are three main oxides that are used as opacifiers: zirconium, tin, and
titanium, although bone ash in small amounts also will opacify a glaze, but
that's not all it does.
Ultrox, Zircopax, Opax, Superpax  are all
brand names of zirconium compounds. One of them, Opax is zirconium oxide; the rest are zirconium silicate. If all
you're doing is making a glaze white and unvariegated, zirconium will do it.
If you want a bathtub white, this is what you're looking for. It's the
cheapest opacifier.
Tin oxide will produce a mellower white if you're just opacifying a white
glaze, and will produce a warmer white than zirconium. It also has a
different effect on some colors than zirconium, particularly iron.
Titanium, whether pure in the form of titanium dioxide, or in the form of
rutile (which is theoretically 92% TiO2, and 8% iron) both opacifies and
breaks up the surface, producing microcrystals.
Which one is best? As usual, it depends.
Paul Lewing, Seattle