What tool works best for smoothing semi rough pool plaster? have a water fed right angle grinder and have been using diamond resined wheels but its taking forever. The aggregate is silica sand and i mixed acryl 60 1:1 on the water( amazing stuff ). ALSO what type of stain will work on the plaster. I am attempting to replicate travertine in a stepped 45 degree pattern. I have used 1 inch strips of tile to act as a guide and look like grout. Came out okm but a tad rough.