Post by Jugglerguy on Dec 18, 2011 16:08:58 GMT -5
My 13 year old son has an interest in rocks and I'm trying to help him learn to polish them. Right now we're working on some Petoskey stones which are fairly easy to find where I live. I need some advice.
A friend of mine recently sold us an old rock grinder that he bought along with a bunch of other equipment from the son of a deceased man. He doesn't know much about it, so he's not able to help too much. We've been using a grinder wheel of unknown coarseness (another says 160 on it, and this one seems finer) and then a plywood wheel with a thin layer of foam covered by 320 grit black sandpaper on top. By using just those two wheels, we were able to polish a Petoskey stone fairly well, but it took long time. It seems like there should be more grits between the grinder wheel and the 320 grit sandpaper. A more aggressive grinding wheel would be nice too. There are about ten different plywood wheels with various surfaces (cloth, leather, aluminum with little bumps, etc.) include with the grinder. We tried some finer sandpaper wheels (500 and 600) and they actually made the rock look worse, so I don't know what the problem is there. We haven't tried polish yet because the man we bought this stuff from just dropped some off yesterday. The polishes are cerium oxide and Zam buffing compound. I'm not really sure which to use.
I'd like to have some replacement sandpaper discs and perhaps a larger selection of grits to polish stones a little quicker. I'm not even sure how to attach the sandpaper to the plywood. Do I peel the sandpaper and the foam off, or does the foam stay on while just the sandpaper is replaced? Does the sandpaper have a sticky back or do I need some sort of adhesive?
Thank you for any advice you can give,
Rob
A friend of mine recently sold us an old rock grinder that he bought along with a bunch of other equipment from the son of a deceased man. He doesn't know much about it, so he's not able to help too much. We've been using a grinder wheel of unknown coarseness (another says 160 on it, and this one seems finer) and then a plywood wheel with a thin layer of foam covered by 320 grit black sandpaper on top. By using just those two wheels, we were able to polish a Petoskey stone fairly well, but it took long time. It seems like there should be more grits between the grinder wheel and the 320 grit sandpaper. A more aggressive grinding wheel would be nice too. There are about ten different plywood wheels with various surfaces (cloth, leather, aluminum with little bumps, etc.) include with the grinder. We tried some finer sandpaper wheels (500 and 600) and they actually made the rock look worse, so I don't know what the problem is there. We haven't tried polish yet because the man we bought this stuff from just dropped some off yesterday. The polishes are cerium oxide and Zam buffing compound. I'm not really sure which to use.
I'd like to have some replacement sandpaper discs and perhaps a larger selection of grits to polish stones a little quicker. I'm not even sure how to attach the sandpaper to the plywood. Do I peel the sandpaper and the foam off, or does the foam stay on while just the sandpaper is replaced? Does the sandpaper have a sticky back or do I need some sort of adhesive?
Thank you for any advice you can give,
Rob