Using Polishing Grit with Glass
Although I'm not a big fan of cold working by hand, I always keep some rock polishing grit handy because there are so many things I can do with it quickly. The most common rock polishing grit is made of silicon carbide. It is a black slightly sparkly powder. As with sandpaper, the lower the number, the more rough or coarse the grit
is.
Grit polishing works by rubbing between objects and wearing away the rough surface on each. When using grit to polish glass, you have to have two surfaces for the grit to rub between, typically, a flat piece of scrap glass and the item you are polishing.
The basic technique is to add a small amount of grit and a bit of water to create a slurry on the sheet of
flat glass, and then work the slurry around in a smooth pattern with your glass piece until it is as smooth as you want. Sometimes, the flat glass is the item you are trying to polish.
Although grit is typically used to polish, or smooth something, I use it as an alternate to sandblasting, by wearing away the smooth surface of the glass to create a uniform frosty texture.
