HOW TO GUIDE FOR FINISHING HARD CONCRETE
Concrete is considered to be hard when it tests above 6000 psi and above a 7 on the MOHS scale. For these floors the initial cut is very difficult and the diamonds have a hard time penetrating the concrete and grinding it. When trying to grind hard floors choosing a diamond with a soft bond is critical. Choosing a diamond with a smaller surface area and in extreme cases wetting the concrete in front of the grinder can increase production rates and help the diamonds cut and stay cool. The recommended operating speed is 5 – 7 on a scale of 1 -10 for large machines with adjustable speed controllers.
On concrete floors with topical curing chemicals the recommended process is as follows:
Process 1 (if aggregate must be exposed)
30 Grit Metal
50 grit Soft BSD or Soft Premium 8 segment
100 grit Soft BSD or Soft Premium 8 segment
Densify
400 grit BSD
800 grit Resin
1500 grit resin
Process 2 (if “salt and pepper” must be exposed)
60/80 Grit Metal
100 grit Soft BSD or Soft Premium 8 segment
Densify
400 grit BSD
800 grit Resin
1500 grit resin
On concrete floors without topical curing chemicals the recommended process is the same as above except the metal step may be removed.