| Description |
Zircopax is a brand name version of zirconium silicate or zircon.
It is often used for semi-opaqueness. In North America, the most popular zirconium opacifiers fall under the brand names of Zircopax, Superpax and Excelopax. These vary according to particle size, the finer the size the greater the scattering of light (and thus the better the opacification). In addition, the finer sized materials contain a little extra silica for maximum whiteness.
Of course, the amount of zircopax in a glaze determines the opacity. Small amounts (1-3%) may give no noticeable difference but are sometimes employed to improve glaze hardness. Since zircopax is refractory, the more that is added the more the degree of glaze melting is going to be affected. Up to 15% or more might be needed to fully opacify a glaze. If higher amounts are needed the glaze formulation may need to be adjusted to reduce the amount of SiO2 or increase flux (to melt the glaze better).
Zircopax affects glaze melt viscosity, surface smoothness, thermal expansion and color development and can be implicated in a range of glazes faults associated with these. Please read the page on zircon for more information.
Zircopax can be used to whiten porcelain bodies, especially for casting, but of course, translucency is lost. |