Grinding, wet or dry?

[tcianci]

A friend want to epoxy his garage floor. It is currently painted. I told him that the paint really should be removed for the epoxy job. He doesn't want to go through the expense of renting a blast trac. I know that you guys have used a grinder with diamond wheels to clean the floors. 2 questions... Do the diamond wheels load up too much because of the paint and 2nd... can you use the diamond wheel wet to keep the dust down. I will relay the answers to him, thanks.

 

[rugerlady]

Most diamond grinders that you can rent have an attachment that you can hook up a shop vac to, this keeps the dust down.

 

[boiler7904]

Seems like this might be a case of never enough time / money to do it right but always enough time / money to do it again.

If it's just paint, he could probably get away with a wire wheel in a hand held grinder as long as he used proper PPE. After that a typical muriatic acid prep should suffice.

Epoxy cures with a chemical bond. With a material like paint between the epoxy and concrete, he's setting himself up for a chance to redo the floor in a few years once the epoxy peels (if it sticks at all)

Cost of renting the proper equipment now vs. cost (and hassle) of redoing the floor down the road seems like an easy decision for me.