Painting Non Ferrous Parts

[forsailbyowner]

Ive noticed that that aluminum and copper parts just dont seem to do well painted with engine paint. I just did a disassembly and the aluminum exhaust manifold, copper coolant pipes etc... had continuous corrosion between the paint and metal surfaces. The exhaust manifold for example held a pronounced white layer of corrosion under seemingly unbroken paint while the unpainted mixing elbow was externally corrosion free. Im thinking the pigment in the paint holds metals that are causing an electrolytic reaction. This time around I used an old hot rodders trick and instead coated all nonferrous parts with clear enamel. Sure makes for a nice looking engine. Thoughts?

[Beersmith]

gotta use a good self etching primer for it to stick.