When I painted my blades black, i used aircraft cleaner, then sanded down the rest and the curb rashes to a smooth finish. After that, i used primer. Then I gave it 3 layers of duplicolor paint with 1 hour in between each layer. After that, i put on clear coat and all done. Aircraft cleaner is a very good product, it could be used to remove old paint and old clear coat too.
Heres a good tip if you are going to paint the rims with tires on: use some 3x5 notecards and slip them in between the lip of the rim and the tires, that way you wont spray any paint on the tires.