Rattle can primer

RRR is right about the expense. Spray cans would be a very expensive way to do it.
1969383S is also right. You really do want to protect bare metal with epoxy primer. Plus you cam do filler work right on top if the epoxy when it is scuffed with some 80 grit.
Here is my $0.02. Go to TP Tools at 1/2'' Coalescing Air Filter .html?b=d*8081
They sell a water separator that does a great job keeping the air dry. it takes reusable filter cartridges that look kind of like toilet paper rolls. They can be dried out and reused many times. Make sure you buy a few extra cartridges. This thing works great. I have one.
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