still confused after all the posts on this as it seems the answer is always clouded..after taking a part, say a fender,down to bare metal and welding in a repair patch, does the etch primer go on first or does the plastic filler work get done and then the etch primer. Can filler go over etch primer?

Originally posted by drptop70ss:
still confused after all the posts on this as it seems the answer is always clouded..after taking a part, say a fender,down to bare metal and welding in a repair patch, does the etch primer go on first or does the plastic filler work get done and then the etch primer. Can filler go over etch primer? There might be an exception SOMEWHERE, but I think its safe to say that filler NEVER goes OVER etch primer. I would say if you WANT to fill over a primer, use an etch first, THEN an epoxy primer, then use your filler. Really, though, why make the extra work? Just do the bodywork first, get it as good as you think you possibly can, then etch prime it all. If you use a surfacer, that will help straighten it out too.

If the WHOLE fender is bare metal, you can always spray the whole thing with etch, and sand off where it is you need to finish off the bodywork. Again, though, why make more work for yourself?

Yes etch can be applied OVER filler. Filler can NEVER BE APPLIED ON TOP OF ETCH. Am no chemist but from my understanding and first hand experience graemlins/clonk.gif when the filler goes thro its chemical reaction the chemicals in the cream hardener react with the acids in the etch primer. This reaction will lift the etch.

This chemical reaction within the filler only happens during the curing stage of the filler. By the time you are sanding the reaction is done. This is why you can APPLY ETCH OVER FILLER.

Just something to think about before appling your etch of choice over filler check the tech sheets on that etch, some you cant apply over. These etches are wash primers which are a stonger form of etch.

But for the most part, PPG's dx1791, dupont's variprime, S-W I believe its EGB?? 980 and 973 can be applied over etch

Originally posted by sevt_chevelle:

But for the most part, PPG's dx1791, dupont's variprime, S-W I believe its EGB?? 980 and 973 can be applied over etch I think he meant applied over filler.Those primers listed are etch primes.
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