Sand the stuff you want to paint with some 400 grit. Wipe clean with tack-cloth. Spray with 4 or 5 light coats of black primer. Let primer dry. Wipe with tack-cloth again. Spray with 4-5 light coats of desired color.
That should hold up pretty well, your only real option for permanent durability would be to get some custom aluminum parts made for you, kinda spendy though.
That should hold up pretty well, your only real option for permanent durability would be to get some custom aluminum parts made for you, kinda spendy though.