Well Phill, if you thought the belt sander was bad, you will be interested to hear that I did parts of panel #5 with an angle grinder and a coarse cleaning pad
I used it to remove most of the epoxy on the panel left after gluing the strips. Quick and easy, and not too risky either in my opinion. Sanding with the beltsander and the foam pad was much quicker and I got down to the stage where I can begin using a fairing board pretty quick compared to earlier. Not for the faint of heart or the Zen builder though