80-Grit sanding discs are ideal for heavy sanding, stripping, and roughing up the surface. Its tempting to buy coarse 60 or 80-grit paper to speed up the sanding job. However, because modern lightweight joint compound is so soft, heavier grit sandpaper is not a necessity. Coarse-grit paper may have a tendency to leave undesirable sanding marks. We recommend 120-grit or 150-grit paper for the best results.