Hope this is the right place to post - I have an acrylic coated concrete deck and I wish to recontour a small portion of it with a diamond cup on a grinder so that rain water runs toward the deck drain rather than toward my covered porch. I'm afraid that the acrylic will "gum up" the diamond cup - Should I remove the acrylic somehow before grinding the concrete substrate, and if so, how; or is the diamond cup going to be suitable to do this?