Joest Abrasives is Simply a Better Drywall Sanding System. Joest drywall sanding products have holes throughout the surface that allow the dust to easily escape, and Eliminate Load-up. Joest Abrasives drywall sanding discs for the Porter Cable 7800 Drywall Sander and Drywall Sandpaper last longer and provide a higher level of finish. Joest abrasive drywall sanding sheets utilize a Non-Woven backing that draws the dust through the portholes evenly. Not only is the backing a nice additional cushion, but it drastically improves the performance and life of the sanding disc. Even distribution of sanded drywall material means you can Eliminate Sand Scratches!