Just a quick question.

Can't tell the best paint, Maybe Powdercoat.
Zinc Chromate is an Excellent primer for Aluminum.

Outdoor aluminum what? I use Rustoleum on aluminum and have gotten excellent results. I usually use 2 coats.

Hi, NOGOGLO!

Yes. Aluminum what, please? It might make a difference as to what brand or type of paint is used depending on the size and use of that which is to be painted.

Thanks!

I've done an Aluminum storm door with laquer a couple of times with very good results.

Was the door exposed to the sun on a regular basis, KISS?

Yes, a front exterior door that get a LOT of sun. Might have painted it every 10-15 years.

And, you did it with a lacquer based paint?

Yep, Rustoleum spray laquer in cans.

Took door off and disassembled it. To paint.

I've air brushed laquer, but don't have spray equipment for larger areas.

I definitely have a lot of stuff could powder coat, but don't have sandblaster, powdercoat gun and IR lamps.

Chairs, awnings and gutters and iron railings to name a few.
It probably would be cheaper to buy.