Mike:
You might want to check into using Phosphoric acid. You can purchase it from paint stores as well as home depot. I use it in a spray bottle on bare metal, scuff it in with a scotch brite, then wipe off any residue with a paper towel. When you are ready to epoxy prime, you scuff and clean with wax and grease remover then it is ready to spray. The phosphoric acid etches the metal and converts and rust to iron oxide so that it doesn't rust as long as it is out of the weather and is not getting wet. The only caveat is that you can't use a second product with phosphoric acid over it (i.e. no etch primer and no epoxy that contains phosphoric acid (Valspar and HOK are two that do. I use Kirker Enduro that doesn't)). Phosphoric acid is sold under many brand names such as Ospho, Chem Prime, Picklex, etc.
I hope this is helpful.
regards,
Steve
New Orleans
