Both have their strong points. Powder coating will provide a more durable finish, so for something like a set of wheels, that could prove to be beneficial. The downside is of course that you have to bake the wheels in an oven. If done incorrectly this can weaken the structure of the wheel. Painted finishes are nice since they don't require the same oven treatment, but the finish won't be quite as durable. If you can find a powder coat shop that has experience with wheels, and does not bake them for long periods of time at high temperatures, I think you should go that route.
Originally Posted by M3 Adjuster
At any rate.. there is an EIGHT HUNDRED degree difference in temps between max temp for powdercoating ( 375-400) and the actual MELTING point of aluminum alloy (1100+ degrees). That is a TON of headroom.
I am sure that it's easy to find people that will recommend one be conservative and NOT powdercoat a wheel... but the math speaks volumes to me... of course... I'm an engineering flunkie. But it seems this is not an engineer's baliliwick anyway... what we need are some chemists and physicsts..
It's not that the wheels themselves melt, it's that they become brittle due to the heat change. If the metal is left at high temperatures for too long (IE: if done incorrectly) the wheel could fail during everyday driving or from road hazards due to 'over-aging' the alloy. There are powders on the market now that cure at lower temperatures for shorter amounts of time though, which makes them ideal for powder coating wheels.