Technical Primer for Aluminum

What is a good primer for use on machined aluminum (scuffed up with some 220 grit)? I'd like to infill some machined pockets with 1 shot lettering enamel or something similar that is high gloss black and can withstand the elements.

 

I use PPG epoxy primer for aluminum but there’s a prep coating that goes down first.

 

In the good old daze, there was a 2 step process to treat the aluminum before painting, then the recommended primer was Corlar. Nowadays, a good sanding and epoxy is probably the best bet.

 

Isn’t there an etch primer used for aluminium?

 

White vinegar can be used as the cleaner and for the etching, lots of folks are painting aluminum heads with just engine paint and no primer with success. Or additionally you can get a can of etching primer....

 

Alodine was used for a time, iirc.

 

Airplanes have all their bare aluminum sprayed with Zinc Chromate

 

chevyfordman beat me to it, Zinc Chromate primer for aluminum was used in the good old days.

Pat