Finishing Aluminum

[zombones]

After painting the aluminum foil on my guitar the color I want it, can I use Polyurethane to add clear coat?

[biliousfrog]

you need a suitable primer for the aluminium, then a paint that will work with the primer & then a clear that will work with the paint...so you tell us, will it work over the paint that you're using, will the paint work over the primer & have you used a suitable "special metals" primer or etching solution on the aluminium?

[zombones]

you need a suitable primer for the aluminium, then a paint that will work with the primer & then a clear that will work with the paint...so you tell us, will it work over the paint that you're using, will the paint work over the primer & have you used a suitable "special metals" primer or etching solution on the aluminium?

The only thing I've done so far is superpaste the aluminum on the bare wood guitar. I plan on spray painting it shiny metal purple. What sort of primer do I use? Will it affect the shiny-ness of the finish?

[GuitarGuy]

My experience with painting aluminum is limited to automotive poly. But what ive found is you can pint over the bare aluminum with no etchant but it does not stick very well ....pretty obvious. The thing is as long as the paint doesnt chip it acts like an eggshell and envelopes the aluminum. As soon as you get a chip it will peel. It held up pretty good on a peavey strat pickguard I had.

[biliousfrog]

yes you can paint directly but it won't actually bond to the metal, just kind of lay over it...the only thing that will help it stick is the small imperfections in the metal. Aluminium, stainless steel & zinc oxidize & create a film that prevents paint from sticking. The solution is to use an etching primer which actually eats into the metal & creates a surface that can be painted. The primer is usually a khaki green & stinks of sulpher so, yes - it will affect the finish

I think that the finish you're thinking of is anodizing.