Epoxy Prep Question?

[MN4x4]

I have a 20 year old concrete floor in my shop. I plan to rent an Enco grinder and grind it down to remove any sealer or surface imperfections, then wash and vacuum it until it's clean. My question is - since I will have ground it to a clean surface - do I need to acid etch it anyway? I want this to be as near a perfect install as a DIY can do,

 

[shaun oriold1]

Its been talked about a bunch of times. IF you grind, you wont need to acid etch, you also dont want to wash it. Just vacuum the heck out of it. Take your time, and it will be fine.

 

[pauls340]

Once you grind it you might notice moisture drive forcing water out of the concrete. That has to be addressed before you epoxy. We just did an ice rink shower that over 30 years old and as soon as we finished grinding, several water spots began leaking. I simply wet down the concrete, allowing the water to penetrate and then we sprayed Vapor Lock 5/5 on the surface.....done.