Originally Posted by Retro Grouch

What are you trying to accomplish?

If you want to mimic the factory finish you are going to have to completely disassemble the wheel, strip all of the old finish off of the rim, sand, use an etching primer for aluminum, sand again, prime again and paint. Your finished product will never be any better than your surface preperation so, if you want a factory-looking finish, don't even think of skimping on that step.