Thanks to all for the input.
I did check with Rustoleum and they recommended rusty metal primer and then a rustoleum automotive finish. I asked about using the Ospho as well and they nixed that idea.
I plan on driving this truck and where I live this means plenty of gravel roads.
My original thought was to use POR15 because I had read that it was tough.
I still have not decided which way to go but I appreciate everyone's food for thought. Thanks again!
Since Rustoleum does not sell Ospho, I am not surprised that they "nixed" it. If I were them, and didn't have any research supporting compatibility, I would not have recommended it either.
I have a 48 frame which was sandblasted and POR-15ed (bad move it turned out). It was left outside with a tarp on it which kept it out of the sun, but not dry. It rusted in a splotchy manner. I then cleaned it with paint thinner, applied Ospho, Rustoleum rusty metal primer, and Rustoleum gloss black paint. I returned the frame to the outdoor elements for 2 years without any rust showing up.
Carl
