rust repair

[LanceG]

Hello! I am restoring a 1970 Ford Bronco. I've been sandblasting the body and replacing panels where needed. However, i am noticing some rust showing at the seams where panels/brackets meet. I can blast most of it away, but I fear that more rust between the panels may eventually deteriorate the spot welds themeselves. The panels themselves are still in very good condition. The way I see it, I have two options: 1. remove as much rust as possible and seal both sides of the seam or, 2. remove the panels, sand the rust, prime the ends and reweld the panels. How is this issue normally addressed? Thanks!

 

[mikeiam82]

You could drill the welds to remove the panels and clean it up but as soon as you re-weld youll burn some of the paint away anyway. This can be reduced by weld thru primer that adds zinc into the metal by the heat and galvanizing the welds. Id say the best thing for you do do is blast as much as you can wash with a special zinc phosphate solution and por-15 the seams then scuff and seam seal. por-15 is a canadian made product that can actually seal the rust, you can paint por-15 on parts and hammer them it wont chip off if applied correctly. This isnt a sure thing but a solid and cheaper solution than cutting all the rust out with is unfortunately the only way to completely stop rust.

 

[LanceG]

Thanks for the information! The more I think about it, the more I'm inclined to just replace the brackets. I'm seeing it mostly on the two core/wheel well brackets where the battery tray mounts. I'm sure years of battery spillage probably contributed to the addtional rust. That body mount is almost shot so I was going to replace it anyway. Since I'm replacing it, I might as well replace the entire bracket. Does POR15 work well on body panels? I've seen it used on a lot of frame and suspension parts, but haven't seen it on body parts. Also, can it be used to seal the seams then topcoated with something else? THanks! Lance

 

[mikeiam82]

POR-15 would work well on almost anything, you cant really go wrong. If your using it on a seam, for example the 1/4 panel lower where it meets the top section of the 1/4, just make sure you clean the seam out as best you can. Spray or brush POR-15 to seal whatever you cant get in and wait for it to dry. Then you need to scuff it and put a flexible seam sealer in the crack to seal any water from ever getting inside. It would act as first defense and the por-15 would work as a second defense against water and air. You cannot leave POR-15 primer open to the elements, it is oil based and repels water but sunlight will break it down so it has to be top coated. Painting over top of it would depend on the paint you are using. Some paints would need a sealer where some may not, but if it is under the body or hood no top coating is necessary unless you want to make it nice.

My original post was more directed to replacing exterior body panels where the seams are seen but if your just replacing the mounts for the inner wheel wells to core support or firewall you could just cut them off weld new ones on and clean up the burn paint easy enough then re paint. POR-15 or any good quality product should be sufficient. Personally ill be sand blasting my entire body after all my panel replacement is done and sprayed with a good quality primer or POR-15. From there ill be undercoating the underneath and floor pans to further seal it all up and ill be golden. Yours may not be as extensive as mine but im doing a complete resto-mod.

Good Luck.