Duct Tape Strengthens Sandpaper
I do a lot of finish-sanding freehand, without a block or support, so I can smooth over curves and edges and get into nooks and crannies. But the finer abrasives are usually bonded to thinner paper and, at least for me, the paper is too thin and ends up tearing long before the abrasive is consumed.
My solution is to back pieces of sandpaper with good old duct tape. It might be stiff at first, but it softens up quickly. The resulting sandpaper can handle a lot of stress and it’s a cheap alternative to more expensive papers. I like to fold a piece of sandpaper in half, put a strip of tape on each side of the fold, and then use the paper like a shoeshine rag.