On frame undercarriage restoration

[tequilaiam]

I've read that products like POR15 or rustoleum are best applied to bare metal/rust. Otherwise they peel the old paint off and can trap moisture where you can't see it.

What's the best method to get the old paint/coatings/grease/tar/bugs/whatever off the underside of a CUCV or any other old vehicle?

In my garage I have a sandblaster, spray guns, "engine cleaner" air tool (compressed air wand w/ venturi for chemicals), grinding wheels, sandpaper and on and on yet don't know if some of these are overkill or too time consuming for something as large as a truck. My experience is more akin to tinkering with small projects and maintaining newer vehicles that need occasional touch-up.

If not mechanically removing old coatings and rust, would a quick spray of aircraft stripper be good or should I just hit it with degreaser and apply the rustoleoum over the old stuff that's not already flaking off? A frame-off project would be ideal but I won't have the space for that unlessI can get my wife out of the house for a few years. I'd also think that chemically stripping old paint off would be **** on any rubber hoses or wire insulation.

What's the general consensus for working smart, not hard on old MVs? Thanks!

 

[mkcoen]

One of the things I've been doing while working on my M37 frame is scraping the accumulated road tar off the undercarriage. I've found a small propane torch works great for loosening it (and undercoating) and softening it enough to use a putty knife to remove it.

The only time I've used POR is after grinding or sandblasting the area first.