Undercoating questions.

[Ranger850]

My bed is off, i want to undercoat the bed and was wondering if just paint would be OK. I plan on coating the frame with something like POR 15 or a2part epoxy paint. The bottom of the bed looks decent. Still covered in a light coat from the factory. Can i just lightly sand and then spray with a couple of coats of Rustoleum?

 

[Bird76Mojo]

In my experience, regular Rustoleum won't last long at all. My next shortbed project the entire bottom and inside of the bedsides will be sprayed with Iron Oxide (red) primer, commonly seen as "Rusty Metal Primer" - I've never seen ANY paint last as long outdoors (with no topcoat) as this stuff does. I sprayed some 1/4" steel that was very scaly/rusty without even cleaning it, and it still looks perfect to this day. No rust "bleed-through" at all. That was years and years ago.. At least 10 years ago I'd say.

I'd scuff it lightly and then pressure wash it with soapy water.

Other common undercoating products make future bodywork a nightmare. They don't grind off easily as they tend to gum up.. They make welding an absolute nightmare.. You have to use very harsh/deadly chemicals like MEK to remove them..