The Question About Concrete Grinding
I’m often asked whether dry grinding can be used to prepare the concrete surface for Omega Concrete Countertop SealerTM. The answer is NO.
Dry grinding is not the same as wet grinding, even with the same 200 grit. Dry grinding/polishing tends to burnish the concrete surface, making it too smooth for good sealer adhesion. This applies to any coating sealer, not just Omega.
Here’s Why You Can’t
The dry polishing process creates concrete cuttings which don’t get flushed away like they do with wet polishing. Because the powdery cuttings tend to remain under the polishing head longer, they break down and act as finer polishing media. This is why dry polishing is more effective than wet polishing when trying to polish concrete to a mirror shine, because the concrete cuttings themselves act as a finer polishing compound than the diamond pad that created them.
Additionally, the super-fine cuttings get forced into the open concrete surface pores, contaminating the surface, and that can cause adhesion failure.
These two characteristics are the major drawbacks of dry polishing, and why dry polishing is not permitted as suitable surface preparation for Omega (nor recommended for any urethane coating sealer).
If you can’t wet grind with 200 grit, use the muriatic acid method. The Omega instructions you receive after purchase contain full details of this method.
The following two videos show how variable your concrete can be depending solely on the surface preparation technique used.