Post rust repair primer best practices
 

As i'm completing my rust repair on my build, i've pondered what's the best primer treatment for all those unexposed areas. Places like the kidney bowl inner, lapped surfaces on the rocker and the like all need some sort of protection. On my driver side I used a PPG epoxy primer and zinc weld thru. Looking at some online sources like Classic Carreras, I see they are using copious "Zinc rich primer" on their builds. It looks like a cold galvanizing zinc paint.

Now that i'm in the middle of the passenger side, I'd like to get some feedback.


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I'm just a beginner, but I would use weld thru primer and after the job spray the inside with some semi hardening cavity protection that can creep into the seams as well as protect the surfaces.
That's what I'm doing an an old 924 I have as an object to learn on.

Would be nice to hear what the pros think...

Por15

when it comes to parts like this you can't get to the back sides once they are welded in place i found SEM RUST-SHIELD works best to paint them with .
i sand the back sides with 180 grit and or a red pad . then you can spray roll or brush on a coat of rust shield .
i'm not a fan of any por product IMO it's over priced and just average quality then it takes forever to dry .
once the rust-shield is dry i grind off the rust-shield on the lip were the part needs to be welded and apply a coat of weld thru primer . one very thin coat of weld primer is all you need on the lip of the part to much and it will weld like crap . weld primers are zinc based being zinc a little goes a long way for rust protection .
once i have to part welded and dressed in ( any grinding ) i stick a spray wand of my undercoating gun up thru the drain hole ( if there is one ) and recoat the inside cavity with more rust shield .