Granite Counter top

[DC_INC]

Hi Everyone,

I am installing 16" granite tile on a countertop and I have 2 questions

1. I have 1/4" CBU over 3 laminated sheets of 3/4" exterior grade ply on a kitchen island. What mortar is best for the counter top medium bed or thin set? I am wrapping the stone around the sides of the island too and will be using thin-set on the sides not medium bed thin set. I just want to make sure the top is durable enough in case someone sits on the top.

2. I bought diamond resin polishing pads (dry polishing pads) and am using a Rigid Orbital sander that has a no load min speed of 2000 RPM. The pads come in grits from 50 - 3000 and I want to polish the edge of the tile but when I polish them it seems like the pads are either burning the stone, or that the color from the pads is seepiing into the stone. I though I was polishing at too high of a speed, but am not sure. Any advice for dry polishing granite using diamond resin pads?

[LGB]

I like medium bed thinset for those larger tile but a regular formula would work too. Are you sure your pads are intended for granite? There are all kinds of different matrixes for different materials. Also be sure to do a good job with each grit before moving on to the next. You can't skip any or you can have problems like you are experiancing.

[Dan V.]

I recently had a similar issue with dry polishing pads. I was using a set to polish edges (flat) on Black Galaxy granite slabs. The boys over at stoneadvice.com assured me that wet polishing was the way to go. Either use the dry pads wet or buy a good set of wet pads. I did the latter and the edges came out perfect. As mentioned above, you need to spend time with each grit before moving on. Also, since you're using tiles and not a slab, I would line up your tiles on your bench and do several at a time. That way, you have a consistent edge.

For us newbies to stone fab, dry polishing is just adding difficulty to the job, especially if you've got one of the harder granites. I'm not familiar with the use of a random orbit sander on stone. All pro fabbers use variable speed angle grinders/polishers with a center water feed, unless of course they have one of the real profiler/edging units.

[Hamilton]

Hi Dave

I use dry pads, and unfortunately they dont work well with all stones.
Some pads, maybe its just the brand, or the make or whatever but some
seem like they need to be broken in first. Once you get the pores opened
up on the matrix they will tend to work a bit better. I would try spinning them
on some concrete somewhere or the back of the tile before throwing in the towel.

A bit unconventional but it works sometimes. If all else fails,
make all your cuts and label them in order with your full tiles and take them
to a granite shop who can wet polish them for you.
If you plan on doing more granite work the investment in wet
polishing tools may suit you,
if not it can get expensive buying all the tools and pads.
Best of luck

[hoosierdaddy]

2 sets of wet polishing pads and angle grinder for $135 on Ebay....got it yesterday and it works great. So its not as expensive as you might think. Also got a 3/8" router bit for $65.

For some reason the site wont let me post urls but just search for variable speed wet grinder and there are deals galore.

[DC_INC]

Thanks for the help Gents. I just bought a variable speed orbital air sander to try the dry pads wet. If I still get the burn marks, I will break'em in on some concrete.

If that fails, I will swear a bit, then go buy some wet pads and repeat. If that fails I will swear some more and give up and take it to a granite shop.

Aprreciate the help.

Dave.