Diamond Grinding vs. Acid Etching: How Concrete Should Be Prepped for Epoxy
By Redline Epoxy
Diamond grinding uses industrial grinders with diamond tooling to remove the weak top layer of concrete, old sealers and coatings, leaving an open, consistent surface for the coating to bond to. Acid etching uses a diluted acid to roughen the surface, but it does not remove sealers or old coatings, can leave residue, and gives less consistent results. That is why professional installers prefer grinding.
What prep is supposed to do
Fresh concrete has a weak, dusty top layer. Garages also collect oil, sealers and old paint. A coating needs to bond to sound, clean concrete, so prep has to remove all of that and open the surface.
Diamond grinding
- Removes the weak surface layer, sealers and old coatings
- Creates a consistent surface profile across the whole floor
- Works with dust collection, so it is clean and dry
- Shows problems such as cracks and soft spots so they can be repaired
Acid etching
- Roughens bare concrete, but does not remove sealers or coatings
- Results can be uneven across the floor
- Leaves residue that must be neutralized and rinsed, adding water to the slab
The bottom line
If a quote does not mention grinding, ask how the floor will be prepped. Peeling is almost always a bond problem, and bond starts with prep. See how we do it on our concrete prep and repair page.
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