Polishing Granite

Bob Mariani

I recently had a granite top installed and the customer is complaining about a small spot that is not at shiny as the rest. It is an area about 5" in diameter. Tried unsuccessfully to fix it. Polished with rubbing compound..no good. Polished with wet diamond grinder pads to 5000 grit.. no good. let new sealer soak in for 30 min..no good. Any ideas on what to try next?

Bud Cline

Some spots won't polish, it's not in their molecular character. Probably embedded slag.

Bob Mariani

Not sure if this is it. The area that needed to be addressed was about the size of a silver dollar. Now after "fixing it" the same effect is 5" in diameter.

BACKWOODS

My granite sub will use superglue to fix areas, they drop it on, let it dry then scrape it level with a razor blade. A bit of polish to the area. Looks good and seems to last, no call backs.

Bud Cline

Probably a subsurface imperfection that gets bigger the deeper it goes - who knows? I wouldn't keep screwin' with it.

Bob Mariani

I think I solved this issue. I only had grinding wheels up to 5000 grit. A factory finish is more polished then this. I needed three more steps. Also I used a flexible backer on the wheel. I needed a stiff one to be sure no swirls are left. (easier to be sure the grinding is perfectly flat). First polish with a black grit pad which is 8500 grit. Next use a buffing pad and tin oxide. Next use a stone enhancer, the granite sealer I was using does not add the dark shine I needed.
Thanks for your help and ideas.

rsss396375

I've had that problem before. If you have some StoneTech Enhancer in the shop, try that localized to the problem area. Give it a chance to saturate, perhaps 3 coats and see if it progresively gets better. It just may be the stone that was in the ground and doesn't like to be polished, but really rare.