Just an old trick of the trade though not of the gun trade, more of the cabinet making trade. Make your sanding blocks out of wood then apply Cork to the working face. I purchased a pack of 12 inch square cork floor tiles from what I remember it had 1 1/2 square yards of cork in it. This appeals to my "don't want to pay a lot streak" the pack still has at least a quarter of the tiles left after more years than I want to remember. You can shape the blocks to whatever shape you require at the time then apply the cork with a good strong adhesive if you want to use them wet, when the cork brakes down after many years you just replace it keeping the block.
