I did the fresh air heater in my 52 last summer, and this is what I did. I sand blasted all the parts. Then I primered with two coats of Rustoleum Rust Encapsulator. I scuffed that and hit it it with Rustoleum Hammertone in Bronze. I also painted the case for the motor with the rust encapsulator, and followed up with flat black Rustoleum. It turned out real nice. I had a fellow who used to restore cars tell me he thought I had found a NOS heater.
