I want to do some body work on several parts of my truck. Then, when finished with the whole thing, I will be painting it.

does either a eurothane 2K primer or and epoxy primer seal and prevent rust from starting again? I want to leave the primer areas exposed until I am ready for the topcoat. I know single stage primer doesn't seal and absorbs water and can rust easily.

thanks.

 

Old school version is DP40 (epoxy)...it can sit for years and not rust. It isn't cheap but works great (now called DPxxLF for lead free and available is more colors). The urethanes are pretty good but from what I have been told by the paint reps, it is not meant to hold back moisture and it will eventually rust.

So look for some type of good expoxy primer and paint away. Remember you can use the epoxy under and over your mud, thus no moisture issues at all. I always pull the dent, epoxy, mud, sand, then after final mud sand I recoat with epoxy. Yeah a tad **** but it works.

Kenny

 

If your looking for the best quality job and have time, do it the way mudge mentioned, start with epoxy and seal up bodyfiller areas and cutthroughs with more epoxy. If you use 2k urethane primer, when you have it blocked out, a final coat of epoxy as a sealer over the urethane will give some long term holdout and chip resistance as well. PPG's dp was one of the best, I don't think the new dplf is in anywhere in the same league as the old dp, and have seen people mention some issues with it. Some have mentioned even after months being able to soften and remove the dplf when wiping with lacquer thinner. Now I think there are better choices of epoxy to be found then the pricey dplf. I haven't used ppg's dp since it went lead free. Epoxy is the only primer that is non porous, but most of them don't have a lot of fill to them or the easiest to sand, so many use a 2k urethane primer over the epoxy for its fill and sanding characteristics. Its fine to paint over 2k urethane primer, but like mentioned, epoxy over it would be better. Any baremetal spots should have epoxy put down, or at very least a primer that states it is a direct to metal type. Although people do use urethane primer over metal, it is not really meant to go over large areas of bare metal.
Use epoxy on your bodywork spots, but if driving around with it, you should really scuff it up and reapply another coat before continuing with additional bodywork, priming or painting.