Bill Turner wrote:

Does anyone have any suggestions for painting aluminum in a way that
will be tougher and longer-lasting than you get with the usual spray
can?

I have a small compressed air paint sprayer, and I'm wondering if
automotive paint might be good, or perhaps something else? Mainly
interested in black or shades of gray. What is the best primer for
aluminum?

--
Bill, W6WRT

Most paint bonds well to aluminum oxide, if it is completely clean. I
think the best oxide for paint adhesion is a porous chromate anodize,
but thermal oxidation is very good, also. If the object can take the
heat, Wipe it with paint thinner, let dry, and bake it in a hot oven
(450 F) for an hour or so to evaporate or oxidize all traces of
surface oil and provide a good surface oxide. Do not touch it with
skin before painting.

--
John Popelish