One thing that comes with me to every job site is a simple block made for hand-sanding. I take a 2×4 and rip it to just less than 3 in. wide. Then I cut it down to 9 in. long. As shown in the drawing above, the resulting block holds a 3-in. by 21-in. sanding belt. This size fits nicely in my hand and is the same size that my belt sander accepts.
Spencer Dobrovolny, San Anselmo, CA