So the airframe is painted and you are wanting to sand? It's no big deal except that it will take a little time. If you are trying to get rid of orange peel then you need to make sure you only use a block with a good grade of wet/dry paper. Generally I start with 800 and a spray bottle of water. Keep it real wet so that your paper won't clog and that the water washes away the grit. after 800, move to 1000 or maybe 1200 and do it all again, using a block. KEEP IT WET, KEEP THE WATER FLOWING. Last you can use some Wizard Diamond cut and an electric buffing wheel. BE VERY CAREFUL TO NOT LET HEAT BUILD UP, BE GENTAL AND TAKE YOUR TIME. DO NOT LET THE SURFACE GET HOT OR YOU MAY GET A DELAMINATION UNDERNEATH. just do small areas at first so that you can get the hang of it, its not hard.
Arnold
Poll