I need to remove a hardset ( not glue type) mastic from a large area of concrete floor.
The mastic is almost as hard as the concrete and must be ground down in order to lay carpet.
I am currently using a floor belt sander with hardest grade paper.
It's moving at just about a snails pace.
Is there a beter tool or a surface prep that might reduce labor time.

Paul Maynard

Maybe try an electric floor scrapper. They're available at rental centers.