Whether sanding by hand or using a sander, you need sandpaper suitable for the material to be sanded and the type of finish you want. Start with a coarse grade of sandpaper and finish with a fine grade sandpaper for best results. It depends on whether the surface is to have texture or is to be completely smooth. The machine you use might be a random orbital sander which uses sandpaper discs. These are available in various diameters and grit sizes. Check which sander you have before ordering new sanding sheets to ensure that they fit. If you have a sheet sander, belt sander or detail sander, you will need different types of sandpaper. In that case you will need to buy sanding sheets or belts that match the shape of the sanding pad on the sole of the machine. Whether sanding by hand or using a sander it is always best to start with a coarse grit sandpaper and finish with a fine grit sandpaper. Coarse grade abrasives have grit sizes of 40, 60 or 80. Fine grade abrasives have grit sizes of 120, 180, 240 and higher. Sanding can be done by hand and it is often easier if you use a sanding block or similar together with the sandpaper for support.