Prepping panels for paint, surface rust & pitting
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I’m busy restoring a old E30 Bmw 3 series, most/all welding is done so far and I’ve also removed any underseal that looked cracked or damage to check for surface rust underneat.
What I’m wondering is, what is the best method to get to metal to a state where I can spray etch primer. So far what I have been doing is using the angle grinder with a knotted wirewheel attachment to get rid of surface rust and underseal. I don’t think this is good enough for getting rid of surface rust, it doesn’t always get rid of rust in pitting either. I find a finner attachement on the angle grinder or the drill does a better job. Any metal I’ve exposed has been given a spray of paint or primer just to give it some protection.
I was thinking of getting someone to blast (sand?) any welding I’ve done and the bits of surface rust I can’t reach with with the drill or angle grinder attachments etc.
Basically how do I get the metal clean enough so I can get some primer on it?
Traditionally, I would have told you to sandblast.
I just recently was introduced to ground glass media blasting.
I wanted to do soda, but when I called my media supplier they turned me onto ground glass. Removes old paint and surface rust, etches the panel, all without warping the panel.
I used a traditional pressure blaster. Worked fine.
crushed glass is the way to go!!
there is a product that you can spray onto rust and it turns it into a workable surface.
Iwata for clears and Sata for base :rock
I’m not sure if I can get ground glass media here in Ireland, another problem is getting someone who has a mobile blaster. The car is on a spit and there’s no way of taking it anywhere because of this.
Whats the procedure for prepping the metal after ground glass media blasting?
De grease, tack and use a direct to metal primer before it grows brown fuzz….
In 2000 I restored a 72 land rover, and we used gorilla something to rebuild the back deck. I have not done much resto work, but we cleared the surface rust, used a converter, then used this gorilla stuff and created a metal like filler in the BIG holes. Not sure what kind of shape that truck is in, but all the work at that particular shop was top notch. Ever car in there was either brand new, or worth 70k plus. I got to work on a drag viper, was fun for a first job in the business. I really had to earn the right to step up big time. I sanded new parts for a while before I got to ever touch a car lmao. But I learned how to mix paint, prep, and do minor body work, plastic bumper repairs, and how to clean a car. So I took what I could with me.
[quote=”99HMC4″ post=21657]De grease, tack and use a direct to metal primer before it grows brown fuzz….[/quote]
Panel wipe, is that for de-greasing or is that something else? Still sort of learning so lots of silly questions.
Might have found some places that do crushed glass blasting, question is have they got portable gear. Will be onto them Monday morning.
No need to degrease. Just thoroughly blow it off several times using a scotch brite pad so long as the surface hasn’t flash rusted. Then either a DTM Primer, Etch primer then primer filler, or Epoxy primer.
I have an etch primer ready for it and also a filler primer to go on after.
I only recently discovered them scotch bright pads (after lots of sanding), they are excellent and so much handier than sand paper!
etch primer generally isn’t used on resto work because most resto work needs bodywork. usually complete panels are totally skinned with filler then blocked down to make flat. you cannot put any kind of filler over etch primer so only use it on panels that are going to just require a filler primer and paint.
I don’t think I’m going to be using fillers, but if I do what do I use? Filler goes directly onto the panel from what I know or should it be applied to a primer?
The only area I might get fillers out is the engine bay but even at that I only intend doing the seam sealer again and any welding that is required and of course paint. Will be leaving the bodywork to the paint guys, any welding I have done has been on the underside, sills, arches none of which can be seen really.
generally for production work filler will go right on the panel. for resto work, a body is stripped, put into epoxy primer then all work is done over the epoxy. this seals the metal, provides corrosion protection and is a good base for your bodywork during the time it takes to restore the car.
Epoxy is the way to go. But If you are going etch remember etch on filler but never under filler. Epoxy is much more user friendly after the rust is eliminated by blasting or treated with converter.
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