So here's the deal. I've begun cleaning up the parts I'm going to be using for my AV8 build, but don't know what to use on them to keep them from rusting up again. For now I'm cleaning them all the way down to bare metal, but plan on filling all the pitting I'm finding on the wishbones, radius rods, banjo housing, frame, etc. A couple of guys have told me to spray everything with acid etching primer until I'm ready to work the parts in order to keep them from rusting back up, but all I can find locally is self etching primer. Here's the questions: 1. What are the differences between self etching primer and acid etching primer? (if any) 2. Which one is better at killing rust? 3. Can filler be used over this, or should it be used before hand? Any help appreciated. Thanks.
Acid and self etch are basically the same stuff. Neither will prevent rust if stored in a place with any humidity. Also some types of primers and finish can't be sprayed directly over the etch primers. I've had best results with cleaning the bare metal parts with "grease and wax" remover and spraying on a few coats of PPG epoxy primer. It doesn't absorb moisture like regular primer and when you get ready to paint just clean off the dust and spray your top coats of color.
General consensus seems to be that the epoxy primer is the way to go. But what about the filler? Does that need to go on before the primer or can it be used afterward?
Prime with epoxy first and then do your filling. The idea is you keep the metal sealed with the epoxy which is impervious to water. All common fillers can absorb water. If something happens that exposes filler to water when the filler is directly on metal then it'll rust underneath. If the filler is on top of epoxy, the water would probably ruin the filler but it doesn't cause new rust.
Go to your local auto paint dealer and get any and all manufactures printed information . Then go home and READ it. Any ques . , call the paint rep .
I deal with metal and moisture issues nearly everyday at work. And then throw on top of that dissimilar metals and the issues that rise from their being joined together. I have tried about every primer out there and a good epoxy primer always works the best. As mentioned it is moisture proof and makes a wonderful base for a long lasting quality finish. Spray on 2-3 good wet coats and when you sand them down you may not need any filler for the pitting. If you still have some minor pitting that needs attention, use a good filler primer (PPG NCP271) or a polyester filler.
Munkee, to specifically answer your last question, I would advise applying filler over the epoxy primer. That way there is no way the metal will rust under your filler. Don't worry about adhesion either, modern fillers stick to good primer...sometimes better than bare metal. One note about epoxy primer, it is sticky as all get out so be extra careful about cleaning your spray gun.
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