How To Sand Concrete Smooth. You can float concrete by hand or by using a machine. The quantity of water you mix in order depends on the aggregate substance, but you’ll want somewhere within 15 to 20 per cent of water.
The grinder is fitted with sanding papers ranging from 60 grit, which is used to even out concrete floor corners and countertops, to 120 grit, which is used to smooth the concrete into a polished finish. Sand the surface and wash the concrete; I suggest using an aggregate free portland cement and sand (or silica powder if its available).
Sand the concrete porch with the diamond disc until the surface of the concrete porch is smooth and free from imperfections, bumps and surface stains.
The smooth texture of sand finish makes it particularly good around the pool area, where it resembles the look and feel of wet sand. Viewing this finish and found it to be an acid burn finish. You can use chalk, string, or tape to mark the area. Do not let the slurry dry on the concrete because it will harden in place.