Frame Paint

Sand blast it and put two or three coats of a proven epoxy primer (not a wash primer /acid etch primer) over the bare metal.

Never, ever use POR-15 over anything of value. Regardless of what they claim, no coatings stick to POR-15 long-term and there's no such thing as a magical chemical/product that turns scale rust into a primer.

 

X2 on the epoxy primer. Even if you needle scale and wire wheel as much as you can and epoxy over it, it should last a long time. I find the Corlar 2.1 to be good stuff. You can get it online pretty reasonable. Mixes 1/1 with activator, no induction time required

 

I have a sandblaster that hooks up to pressure washer. Used it on frames some. Also a small handheld spotblaster similar to the Harbor Freight ones but a little better quality, I think. It is great for blasting around bolts hucks etc on frames. Then epoxy prime. I have also used Duplicolr bedliner in the aerosol can. Not the rubberized stuff. This stuff dries hard. But if anyone does this ahead of top coating be advised let it gas out for a week or two. I got in a hurry once and shot topcoat of acrylic enamel too quick and it washed right off. So I sanded it good and flat and it has been great. Starting to need spot blasted around a few bolts. Good idea to check torque on fasteners that have rust around them.

 

Not my experience.

 

That's pretty much it in a nutshell. Something to stop or slow the spread of rust and then something to cover it so it looks a little more presentable. I've been doing a bunch of reading about converters and encapsulators. They look like a good base to put over top what I knock off with a brush then top coat it with Rustoleum. Was planning on doing my trailer too with the same process.

 

Tightly wrap them in place with at least 2 layers of aluminum foil.
That will protect your wiring looms and air lines from damage from sand-blasting.

 

I'm hoping to find something that's safe to use on them.