Baldor 332B 3/4-Horsepower 1800 RPM Heavy Duty Industrial Bufferhttp://www.amazon.com/Baldor-332B-4-Hor ... entries*=0
[I got mine direct from ACME and it was a bit cheaper, couple years ago though price may have gone up]
I tried another much cheaper similar buffer first, was pure junk that almost shook itself apart in a week. Returned it, got this and never looked back. So smooth and well balanced it is a joy to use and should easily outlast me. Baldor has been making quality tools for a century, still made in the USA, well worth the investment if you think you can use a tool like this.
Comes in handy for any number of things besides plexi of course, I would be handicapped without this thing.