I've been using electric sanders for years, Blupen and they work fine. Bondo dust is especially fine and if you use a vacuum attachment it keeps things MUCH cleaner. I do recommend a long board to get things really flat, but that is dry (and by hand!) Wet sand your final primer to get it baby smooth- get a buddy to help push it out that day 'cuz you don't want all that water in the garage anyway- I let the hose run the entire time as I wet sand,by hand- of course, playing it across the area continually. Good luck and hope it's in paint soon!