Opinions on acid/chemical dip for panels, and alternatives

[ck80]

Am I seeing things or do I spy a stamping that says your fender in the last picture was made in Taiwan??? I don't even know what year you're discussing, but I'm guessing the OEM didn't have it made in Taiwan. Or am I missing something?

Edit: Oh, I see that the shape appears to be the 73-80 GM truck fenders.

You're not wrong. When gm stopped making them the somewhat worn tooling was sold overseas. This thing was a piece made off that gm die tooling.

So, crimp lines a little less crisp on the fold overs (like the doors wound up near the end) but alignment generally works OK, better than repops made off new tooling and more questionable metal... not that the recycled can metal of the 70s was the best.

But yes, 73-80 stuff all the same. For me mounting point geometry means more than crispness of line for one big reason - I'm going to be using the full body trim pkg, and that covers the body lines.

 

[superbon54]

Thanks for the feedback so far, but.... Well, I'm not interested in any type of "encapsulator" or "neutralizer" coatings. There are so many seams at so many angles, it's not going to seal it all, it just won't.

Here's some pics of the volume of seams. Basically the whole perimeter is involved.

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The amount of flipping, twisting, contortions, and then having exposed surfaces where the stuff is glopy drippy, running, what have you.... not for me. Plus, that's just a cosmetic bandaid... even if it did fully penetrate (which I doubt) it's not removing the rust which is what I'm after. Still, for a broken truck repainted blue once they're pretty decent compared to Chinese.


Any recollection on how long they recommended you wait, and, did that apply to everything or just the parts that weren't e-coated?


If there was a set/pair of nos ones within driving distance and not owned by a crackhead asking over $1000 I'd gladly go that route and save time/effort. But if I can put less than $400 each into getting what I have rust eradicated and straight I'd probably be willing.

I've got a used but straight and unpitted OEM core support and brackets setup, plus wheelwells, I plan to have dipped and powdercoated once I find a place for it. My hope is someone will be able to handle the fenders too, but, I need to know what to really look and ask for. Never went down this road before.

It was about a week to wait IIRC, reorienting the parts every couple days to “drain out” any remaining solution and it was only on non e-coated parts. The dip/e-coat process took a little over a month in two separate facilities 400 miles apart so I’m pretty sure there was adequate dry time between processes.

 

[Longroof79]

There were businesses that would submerse your body panels, and even whole bodies. The process would strip all the paint and plastic filler off the panels and would neutralize any surface rust, etc. The only thing is, prior to painting the panels, the chemical would need to be washed down with water. The one downside to this is that the bare metal would need to be coated as quickly as possible because it will start to flash rust.
I had a few panels done by this process over 30 yrs ago on my other car, and many of these establishments are no longer in business due to EPA regulations.

I think this is what Superbon is referring to.

 

[jlcustomz]

I'm on a painting forum & most people on there don't care for por-15 or any similar products, especially on panels. First of all, it's still best to remove as much loose rust as possible. You should never just paint over rust if you care. Now cavity wax, everybody professional there agrees on being a good thing for hidden areas. Also agreed upon there that a few coats of quality epoxy on cleaned up metal is the best treatment where possible. Not too familiar with acid dips, but some can leave stuff that epoxy may not properly bond too.
Now me personally with what little or light rust I've had to fool with, I'm both cautious & cheap. I'll sand and power wire brush from several directions where there are pitts on the metal. A few wire brush splinters in the skin never hurt anyone.

OK, just kidding. They do sting a little.

 

[CopperNick]

Just wandered over from the Non G-Body forum where I had posted about the progress I had made in stripping my frame rails down to bare metal in preparation for recoating them.

Yeah, I get panels are substantially lighter and require more consideration when hunting rust but a few things cross over. First, have to agree about dipping; it does get into the cracks and crevices if the panel is left submerged for long enough but getting all the cracks and seams and overlaps both clean and dry post dip can be a prolonged exercise and frustrating as you tend to think you got it all and then a thin runnel of dip appears out of nowhere and drools down an edge or face.

Would not suggest normal mechanical stripping but have heard good things about soda blast at low pressure. Thing to look for is a shop that has a good reputation for that kind of work.

Although what I am doing to rehab my frame rails is no where near to what you have in mind, it still might be possible for you to use SEM Rust-Mort, which is a liquid and introduce it into the cracks and crevices of your panels along the seams and edges. For what I am doing I use a roller and a brush but I have also put the stuff into a generic plastic bodied pump bottle and sprayed it onto large surfaces or into tight areas or where there are multiple layers to deal with. You might have to employ several applications just to be sure and when dealing with seams, for myself I would probably have the panel standing upright so that the seam being addressed is at the bottom and looking up. Gravity can be your friend when trying to saturate the metal folds. There are also several bio-green rust neutralizing products out there and available by the gallon. Grey plastic bottle, sort of yellow label with rusty brown lettering; name escapes me, have a gallon out in the shop that I am using to rehab a vintage motorcycle wheel. Very large Aluminum disposable turkey roasting pan works great as a basin to sit the wheel in. Can check the shop tomorrow for that name.

After that our ways sort of part because my next step will be to apply a coat of POR-!5 over my RustMort. Again, done by roller and brush. After that there will be applications of Krylon Anti-rust flat black and Duplicolor, also semi-flat black. If I can squeeze in an extra day, I might even go for the gusto by topping it all off with a coat of 3M black undercoating. Your opening post is specific that you don't want to deal with encapsulators; Cool.

As for dealing with panels that come back from dipping or stripping bare-naked, Grey Epoxy Primer works well as a primer sealer to protect the metal from flash rust. It does not have to be removed if a skim coat of filler needs to get applied, just lay the skin coat right on top of it and commence to block sanding. To get it into tight areas and under metal in multiple layers, it can be thinned down slightly more and literally poured into the cracks and crevices; do this on a tarp and outside because, being runny, the stuff will find ways to escape, which tells you how far deep it has gone and where. Pour more as necessary.



Nick

 

[James84SS]

Been going to American Metal Cleaning in Toledo years. They do nice work. Look them up online

 

[CopperNick]

Evapo-Rust. Method involves soaking. Not sure of the max size of any panels you'd be pickling but it occurred to me that large size wading pool for a child might have enough bottom area that you could lay the panel flat and then pour the solution over it. Probably require a couple of gallons but the stuff is both recoverable and re-useable and bio friendly when it come to disposing of it.



Nick