[Silverback]

I’ve rolling fender lips and fixing a bunch of stuff hidden under some bondo on the back of my new project car, and I’m trying to make every effort to prevent future rust.

I’ve had to use the stud welder in a few places to get stuff right where I want it (so far everything I finished shouldn’t take much mud, really everything looks like I’m just going to wipe it with a skim coat and go, I doubt that I need more then 1/16” anywhere, I’m pretty anal retentive when it comes down to it).

What I’m wondering is if it’s OK to wipe it down with some metal prep (or if I run into a spot that had more rust even navel jelly) before I skim it to MAKE SURE that any rust that was there is gone? So far I’ve been using a nylon wire wheel (quickly removed bondo without removing much of anything else so I can see what I’m dealing with first) and a 36 grit roloc to cut down to the bare metal where I have to do some work so the surface has a nice bite to it.

I understand that the phosphoric acid in metal prep can do weird things with body filler (keep it from setting up right I think), but they recommend washing it with water to neutralize it, which makes me think that this is all going on on bare metal that I’d just be causing rust.

What do you guys do? Am I better off skipping the metal prep, just finishing my stud puller/hammer work, hitting it with the 36 grit again and slap on the filler (not sure how much I trust that to get rid of any surface rust that might start while I’m working)? Maybe 60 grit instead of the 36 just to make sure that the grit actually touches more of the surface? I’d really feel better if I use some metal prep, but I don’t wan to hurt anything that goes over it (and this would be a totally different deal if I had the whole body or even a large section totally stripped).

[61 chevy]

Do your metal work...epoxy prime for corrosion resistance...then your body filler.

[adtkart]

^1 hit it pretty much on the head. Once you get the metal where you want it, go over the panel with whatever grit the epoxy primer manufacturer recommends, and apply the epoxy. The filler can be applied over the epoxy. If you have some minor rust, you can use Naval Jelly to remove it, clean the surface, sand with the right grit and epoxy.

BTW.. There is a post on removing rust that was done by Randy Ferguson. It is very detailed, and he is a metal working master.

Aaron