Converting sander/polisher to grinder

Darwins Child

I have recently patched some salt-spalling on the low-point of our garage floor using quikrete sand/topping mix and, try as I might, I could not level them with the rest of the surface of the floor. The patches are raised above the floor approximately 1/16", or perhaps as much as 1/8", which makes squeegeeing the floor more difficult than it should be.

I'd like to grind the patches down to pretty much even with the floor surrounding them and then finish that part of the floor with some epoxy floor-coating specific for garage floors. The area of the floor that contains the patches is no more than 9 ft2. The patches themselves add up to a total of maybe 4 ft2.

I figure that the patches can be ground down with a grinder in under 15 minutes. A rental place has quoted $47 for a so-called dustless grinder and $25 for the grinding disk for 1/2 day, plus tax. I'm seeking an alternative.

I have tried our son-in-law's belt sander, but it's inappropriate for this job.

I've seen some youtube videos of water-lubricated concrete countertop grinder/polishers, but nobody rents them around here.

I've got the very nice variable speed 7" Hitachi sander / polisher shown in the photo below. I also have a shop vac to suck up dust as it is created.

Is there a kit that converts a polisher / sander into a grinder of any diameter?

Thanks.

Attached Images

sander polisher.jpg (157.1 KB, 8 views)