2 things of interest to this post. I have in-laws who restore tractors and I have helped them paint several. They use rustoleum on several colors and they blend the colors to make a few. Also they use xylol to thin it and make flow good, and they use Mar-hyde hardener (Wet-Look). Usually the ratio runs about 3/4 pot of paint, about an 1/8 a pot thinner and top it off with 2 oz hardener. (In a quart cup) I have yet to see one with discoloration near the exhaust or on the engine. They say the hardener gives the paint more durability (I don't know but it shines like hell)
The other part. Someone asked about frame priming. Rustoleum makes a rust locking primer. Its a copperish brown color. It's not anywhere in the ballpark with POR15 but it does work. Raced dirt track for years and used it. We would build a car, wipe it down with paint etcher, and spray over rust and all with the stuff. Followed by rustoleum over that. I have lots of parts and cars out on the farm, and all of them with that primer under the paint and none have not lost any paint or rusted through.
Rustoleum is good stuff for the money.
