[Wavery]

I have painted a few trailer frames in my time. I would recommend NOT using aerosol spray cans. They are 90% solvents and thinners that evaporate and 10% paint.

I recommend using an airless sprayer. You can lay down a much thicker layer of paint. Although, I would also recommend laying down one thin coat first, allow to dry for an hour, then lay down a finish coat.

Aerosol paint runs very easily, even though it is a thinner coat. When you spray with an airless sprayer, you use very little (if any) thinner and you can get twice as much paint on without running.

Care must still be taken to avoid runs. 3 thin coats with an airless should look great and last for years. All of the work is in the preparation, don't waist all that hard work by using spray cans of paint.

You can buy Rustoleum paint by the quart or gallon.

The problem with bed-liner paint is that you can get pockets of moisture and corrosion and not even know it because the stuff makes a "Shell" over the area that is is covering. This shell could have nothing under it (over time) and you wouldn't even know it until the frame actually crumbled. It's far better to have the corroding metal expose itself by having the paint give way.