Polishing Granite

This thread covers a helpful topic: polishing scratches out of granite tops. June 18, 2010

Anyone have experience polishing granite? I have a slab that a customer gave me to use for an island. I profiled the edge and polished it fine. Unfortunately this piece was a remnant and when I went to machine, there was a scratch on the face like someone put their grinder down before it stopped spinning. I also have a couple of small swirl marks that I didn't see. Trying to be the "nice guy" and offering further proof that no good deed goes unpunished, I tried to polish out the scratch. Now the whole top is blotchy and the scratch is still there. I brought it down to 100 grit and worked my way back up to the 3000. Any ideas or do I just need to drop it back down a few grits and use the old elbow grease until they are gone?

Forum Responses
(Laminate and Solid Surface Forum)
From contributor D:
So you're saying the top scratch did not come out by starting at 100g? Was that a 100g diamond resin pad? Scratch marks may be too deep. A 50g or even 30g may be the ticket. If using resin pads, are you using them on a variable speed grinder? What is the granite? Dark or light? Density?

From contributor R:
I am using a variable speed wet grinder 0-4500 rpm. I have the resin pads from 50 to 3000 grit. Unfortunately when I originally polished it I thought it was all set, although it was getting quite cold and dark out and I was soaked from the grinder spray. I was involved in getting the rest of the kitchen finished and didn't see the scratches until I was loading for delivery and the light hit it just right (talk about an oh crap moment). So after the panic set in I spent about 4 hours with the finer grit pads, to no avail. Fortunately the customers are very understanding and this is their summer cottage, so there is no pressure.

So I should probably just start over with the coarser grits and work my way back up? My main concern was that the 3000 would not be sufficient to get that mirror finish back.

From contributor D:
If 100g did not do the trick, go to 50g, which you should have if you bought a 4" set. If that removes the scratches, simply go through the steps again. If after 3000g the shine is not to your liking, hit it with buff, which also should have come in the set. Buff (black or white) depending on the manufacturer equates to 5000g or 8000g.

A lot of our customers make things out of remnants and they usually have some nasty scratches in them. Diamond Productions Canada makes a pad that is a cross between a resin pad and a turbo cup wheel. Although they come in all grits, the 30g will remove any scratch quickly.

From the original questioner:
Those are the type of pads I am using. My experience where stone or ceramic work is concerned lies mainly in small tile jobs, so I am a little out of my element on this slab. The edge I profiled came out great but I think I made more work for myself on the top. I will try the 50 and work back up from there. If the 3000 isn't shiny enough, I will try the pads. The slab is a very striated brown - dark brown and light green - so probably the light buffing pad.

From contributor D:
Whatever you do, after you achieve the desired finish, seal it! Can't tell you how many horror stories we hear and try to bail folks out of, all because the tops were left like a sponge to absorb anything and everything.

Not to mention the undermount sink falling out. Tends to happen when the only thing holding it in is silicone.