|Monthly Tech-Tip |
This slurry is just water and 295 mesh silica. I have mixed it to 1.79 specific gravity and it is creamy. It applies like a glaze to bisque ware (if I dip it fast) and goes on super smooth and even. It does settle, but only slowly. Unlike feldspar and nepheline syenite, if I thin it a little and add powdered epsom salts or vinegar it does not gel, no matter how much I put in. The only response I can see is that it appears to settle out a little less. I was always taught that clay is needed to suspend things, every thing else will settle out like a rock if there is no clay present in the slurry. Of any material, this is one that I would have expected to settle out the fastest.
In ceramics, glazes are slurries. They consist of water and undissolved powders kept in suspension by clay particles. You have much more control over the properties than you might think.
Silica, sold as a white powder, is pure quartz mineral. Quartz is the most abundant mineral, it is pure SiO2 silicon dioxide.