Pick the right sander for the job! Sometimes it is a bit of a challenge to know what the right implement is, hopefully this guide will help steer you in the right direction.
First consider the shape that needs to be sanded. Broad, flat surfaces need a broad flat sander that is very stiff. You need the stiffness to ensure the surface stays perfectly flat. If you were to use a large piece of sanding foam, for example, the flexibility of the foam would work against you as it would flex and round off the corners. Keeping the piece supported on a rubber block will give you better positioning and accessibility to the entire working surface at once.
Tiny spaces or small curved shapes are easiest to refine with sanding needles: hard plastic with tapered ends covered with grit.
Very narrow flat surfaces benefit from a narrow sanding stick, as do interior flat surfaces.
Contoured surfaces like rings are easiest to deal with using a flexible sanding sponge. The foam will form itself to the shape of the piece and will ensure that you don’t sand any flat spots on a curved form. These are available in large sheets that can be cut down to a comfortable working size. I usually trim them to 1″x 2″ pieces.
Next, consider the grit. Grit rating refer to the number of particles per inch: sandpaper with 80 grit only has 80 particles per inch so that is way scratchier than 2000 grit papers that have 2000 particles per inch, hardly abrasive at all. If you are in the first stages of refining/shaping edges, go with something rather coarse like 100-150 grit. The coarse grit will remove the most unwanted material with the least amount of pressure, minimizing the risk of breakage. Use a medium grit, say 220, if there is not much to do. A fine 320-400 grit is used to remove any scratch marks from the earlier work. On broad smooth surfaces, finish with 1000-2000 grit to make polishing to a mirror finish even easier after firing. To shop, click here.