So I've been doing a lot of research on this lately and thought it might be relevant here for the folks that want to polish stuff. Since most of the polishing I do is on small parts that need to be treated lightly, I don't do anything aggressive. Changing sear geometry or contact is bad, m'kay. So I start with Simichrome, move up to Mother's Mag Polish, and finish with Flitz.
Anyhow, knowing what grits you are working with is pretty important with polish, yet I couldn't find anything that actually said what grits where in these. MSDS doesn't say contents, so I did more googling. First off, I didn't know this one, but wear gloves when using all three of these. Seriously. Pretty decent solvent content of kerosene, alkaloids, ammonia, naphtha, etc.
All three have friable aluminum oxide in different amounts and size, so they break down and get finer and finer as you polish. Sizes are based off googling btw, from other discussions where people called the manufacturers, etc. Micron to grit is ballparked off the
Gesswein Canada conversion chart. Mind you, take this post with a grain of salt, as I am not a materials engineer. Also make sure your compounds work with what you are polishing.
Simichrome is around 10 micron, so ~1800-2000 grit
Mag Polish is around 4 micron, so ~5000 grit
Flitz is 3-3.5 micron, around 7-8000 grit