Rust prevention coating for new truck

So the guy I bought the truck from drilled holes in the fenders to bolt on Ebay flares that didnt line up...

I'm putting oem flares back on in the right holes but I want to make sure she's not growing rust under the flares from those new drilled holes.

How should I go about sealing them? Do I need to treat the back of the panels as well? All holes are covered by the flare so blending/ color match should not be an issue.

Thanks guys

 

I might even think about putting something over the holes on the back side to seal up the hole. Not sure how to go about doing that. And then paint.

just the slightest chip on an edge is gonna rust. So seal ‘em up good.

??

 

I spent more than a few years in the (industrial) painting business, so I'll give you my 2 cents. The vast majority of the corrosion protection in your painted body panels is dependent on the bare metal surface preparation and the electrodeposition primer. The basecoat / clearcoat is mostly for appearance and UV protection. The previous owner broke through all of those layers when he drilled the holes and depending on where you live, that could be a problem. If you live in Arizona where its dry and they don't use road salt, what you have to do is pretty simple and corrosion should not be an issue. If you live in the rust belt like I do, you have a much tougher proposition. I'm also going to assume the holes are covered up with the flares.

If you live in Arizona, I'd recommend applying something like Loctite Extend Rust Neutralizer (see link below) or something similar to neutralize any surface rust on the bare edges of the holes.

https://www.loctiteproducts.com/en/...reatments/loctite_extend_rustneutralizer.html

Then I'd apply a primer and something like Rustoleum paint to protect the primer and seal the surface. As has already been mentioned, you need to make sure the back side is coated as well as the front. If you're not too worried about longevity, you might even be able to substitute a good marine grade caulk / sealant for the paint steps. Note that this isn't a cosmetic fix, but more of a functional fix. If you need a real functional and cosmetic fix, you need to go to a paint & body shop and have them do the whole job.

If you live anywhere near where they use salt, or you want a functional and cosmetic fix, the only real option is a body shop. The reason for this is that corrosion will start at the edges of those holes and creep under the paint. This will eventually show up as bubbles under the paint and get real ugly pretty quickly. Many people think that dabbing a little touch up paint on a bare metal surface will stop rust. Unfortunately, they're very wrong.

Good luck!