overspray,Here's the way I was preping the metal before spraying epoxy. I used duponts 5717s and 5718s to clean and 'convert' the metal. then I sprayed their dtm epoxy ,and uro primer . I started doing this after a repair on a 70 superbee where I used a ppg epoxy primer and for some reason it peeled off completely.again I followed ppgs reps info. so I started using dupont . I couldn't post duponts info but maybe you can. (new at computer thing) they have one that can be used under bondo.can you make sense of their info for me ...thanks.
From the way I read the tech info on the Dupont site for DTM epoxy primer sealer, the part number 2580CR (chromate) was the recommended product for under body filler at 1.0 mils and dried overnite (16hours) or baked at 140degrees for 20 minutes. Of course this was over properly prepared metal. The chromate variety of this primer was the only one specificly recommended for under body filler. A similar epoxy- Hot Hues DTM epoxy primer sealer was also listed as good for use under body filler with the same mil thickness and dry times. This goes along with the info I previously posted concerning proper prep, full cure/dry time and that products with chromate have better rust and corrosion inhibiting qualities. Rust/corrosion inhibitting does NOT mean rust nuetralizing or proofing. It means that it inhibits (slows down) the process of corrosion. Lead and zinc chromate are added to primers and paints because of their dense and large molecular structure which helps make a barrier against moisture and UV thereby helping slow down rust and corrosion. Because of environmental and health concerns, fewer primers and paints contain these products. Go back to the Dupont automotive products site and reread the tech for the epoxy primer/sealers. overspray
curbdogs-I had a friend/body shop owner who had several failures/peeling with NCP primers over bare metal. You should probably recheck the tech info thouroughly and see if you followed the correct application steps and products for that primer before you proceed. overspray
This is the way I was taught 35 years ago. Bare metal/mud/epoxy primer/spot putty/high build primer/paint It's never steered me wrong, I have jobs still looking good that are at least 10 years old. The only weak link in the way I was taught was that we didn't have urethane with the base coat/clear coat system. The 'new' product was acrylic enamel with hardener.....man what a joke as far as the longetivity aspect went. -slacker
Question: If I have a freshly sandblasted 'A' body, what do I put on it to keep it from rusting .... then start slapping bondo on?
Yes, it's back up from the cellar......... this is where I seem to get confused. Archived threads state that the Bondo should be applied to bare, ground steel. This old body will be more than likley covered 100%. So, are you saying that you 'DP-90' it, then sand it back off to then apply the bondo's ?
I've always been told that you seal the metal with DP90 or such after all the metalwork, then any bondo can go over that, then your mid-coat sealer and paint. When I asked this question it was because I had heard conflicting stories. It seems to be split, so I just go with what I know....
You can put bondo over bare metal or epoxy primer *only*. Since you're working with a sandblasted body, I would *highly* recomend you sand it down with a DA/80 grit, & epoxy prime it *right away*. Anything you bondo after that I would scuff it by hand with 80 grit before applying bondo. 35+ years doing body & restoration: my paint jobs look good after *decades*. ~ Paul aka "Tha Driver" Easy on the Giggle Cream!
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