Try to find some old paint with lead in it!! /forums/images/graemlins/grin.gif Why do you think the green in the old JD tractors last so long and when they banned it the new paint was crappy for a few years until they found something better.
But if it's an implement just get a decent brand and brush it on. Don't bother with the spray cans for the big stuff because in a 12oz can there may be 4 oz of paint, the rest is thinner. Also we use to paint oil field skids with epoxy, no primer, just bare metal. I've used some in the spray cans for small stuff and it works ok. Haven't really looked for it in a can. The stuff we use to use we had to mix the paint with hardner.
BTW I paint my stuff black if I'm repainting (implements), it helps dry out the moisture when its in the sun.