An interesting aside to the powder paint story---Volkswagen of Canada had an alloy wheel plant in Ontario, Canada. All of the aluminum cast and cnc machined wheels were powder coated with clearcoat powder paint. It was far too time consuming to mask off the wheel nut sockets, so they asked me to design a vacuum gun to suck the powder out of the wheel nut sockets before the wheels went thru the big oven that melted and "set" the powder paint. (If painted, the paint eventually compresses and the wheel nuts come loose, a big liability issue.) I designed some of the strangest looking "guns" that you ever seen. They had a pistol grip, a 12" long barrel that fit into the center of the wheel, and a big starfish shaped attachment on the barrel, near the grip that had either 4 or 5 (depending on which wheel it was being used on) hollow barrels that had ends shaped to fit into the wheel nut pockets, with a series of holes all around the end, attached to the outer end/faces of the starfish arms. There was an air passage thru the pistol grip, out thru each arms of the starfish shaped piece, and down the secondary barrels to the ends which fitted into the nut pockets. There was a connection on the bottom of the pistol grip that was attached to a very powerful vacuum system. The wheels were hung on hooks on a moving conveyor to go thru the heating oven, and some poor operator had to stand there all day wielding that vacuum to clean the powder off the wheels. It was said that at the end of a year wielding the vacuum gun, these operators made a lot of money betting on their prowess at "arm wrestling" other members on the plant floor, and I don't doubt it a bit!!!