Polishing Basics
Polishing concrete is very similar to sanding wood. Machines equipped with diamond-segmented abrasives (akin to sandpaper) are used to grind down concrete surfaces to the desired degree of shine and smoothness. As when sanding wood, you gradually progress from coarser-grit to finer-grit abrasives. The result is a glossy, mirror-like finish. You can polish concrete using wet or dry
methods. Although each has its advantages, dry polishing is the method most commonly used in the industry today because it's faster, more convenient, and environmentally friendly. Wet polishing uses water to cool the diamond abrasives and eliminate grinding dust. Because the water reduces friction and acts as a lubricant, it increases the life of the polishing abrasives. The chief disadvantage of this method is the cleanup. Wet polishing creates a tremendous amount of slurry that crews must collect and dispose of in an environmentally sound manner. With dry polishing, no water is required. Instead, the floor polisher is hooked up to a dust-containment system that vacuums up virtually all of the mess. Summary of the Basic Polishing Steps
Remove existing coatings (for thick coatings, use a 16- or 20-grit diamond abrasive or more aggressive tool specifically for coating removal, such as a T-RexTM). Seal cracks and joints with an epoxy or other semi-rigid filler. Grind with a 30- or 40-grit metal-bonded diamond. Grind with an 80-grit metal-bonded diamond. Grind with a 150-grit metal-bonded diamond (or finer, if desired). Apply a chemical hardener to densify the concrete. Polish with a 100- or 200-grit resin-bond diamond, or a combination of the two. Polish with a 400-grit resin-bond diamond. Polish with an 800-grit resin-bond diamond. Finish with a 1500- or 3000-grit resin-bond diamond (depending on the desired sheen level). Optional: Apply a stain guard to help protect the polished surface and make it easier to maintain
