All of the methods described above will work. I used Por15 on my frame. It will “bite” nicely to sand blasted metal. If it is smooth metal, forget about it. The secret to using Por15 successfully is in the preparation of the metal. You have to follow the system exactly.
1 – Sand blast
2 – Remove all possible oils or blasting residue with Por-15 Marine clean (love this stuff)
3 – Etch metal with Por-15 Metal Ready (I used Eastwood’s Fast Etch, same thing)
4- Rinse with water (lots of it). Frame will flash rust but that is a good thing, better grip.
5- Paint with Por 15 black, let dry for a few hours (I was in a hurry and skipped this step)
6- Paint with Por15 Chassis Black
The finish will not be as smooth as spray epoxy or powder coat but will be very durable and looks pretty good. If it ever chips, you can touch it up with more Por15. Try that with powder coat.