Inner Panel Rust Treatment - Decklid

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mopowers

mopowers

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At what point would you guys consider separating a decklid to treat rust??

I'm trying to decide whether that's necessary for the decklid on my '66 Dart build. All of the exposed metal is solid, but as you can see in the photos, the inner structure/metal is rusty - to the point where a couple pinholes are poking through. I'll obviously be repairing the pinholes with fresh 18g metal, but I'm curious what you guys would do.

The other option I'm weighing is treating it with phosphoric acid the best I can. I'm kind of leaning this way because the thought of trying to get the trunk panel gap as good as it is now once it's split sounds like a total pain in the *** and the car is just a hotrod - definitely not shooting for perfection here. What would you do???

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Here's a spot where I experimented with some acid rust treatment (below). It seems to do a decent job, but I doubt I'll be able to reach every spot that needs it.

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I wouldn't worry about surface rust as you can easily blast or treat that. Its the seams that concern me. My deck lid is rough too. I am considering cutting the bottom lip out in once section and perhaps breaking the lower seam so I can pull it back and blast and treat it. I got a lot of other body work to do first so I will look for another deck lid in better shape before I go down that path. Its a 70 so deck lids are relatively easy to find.
 
I'm no expert, but it looks good in the area that you treated. I would pour it in shake it around into the corners and crevices.
 
Jim Lusk said:
See if you can have it dipped. That's the only way to get to the rust in the crevices.
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Yes, have it dipped. It won’t cost that much and by the time your done with treating it with whatever, you’ll be ahead money and time wise. Dip it, seal it, repair it and paint it.
 
Kendog 170 said:
Ive had good luck with this.
rust mort - Bing
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4spdragtop said:
Krud kutter "Must for rust" in a spray bottle works awesome.
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Those are similar to the product I use (klean strip concrete-metal etch). They're all Phosphoric acid based of various strengths. Looks like the Krud Kutter is weaker - <20%, whereas Rust Mort is 40-60%. Le believe the Klean Strip stuff is ~40%.

TF360 said:
I'm no expert, but it looks good in the area that you treated. I would pour it in shake it around into the corners and crevices.
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Thanks. I'll probably give that a shot first. I'm just not looking forward to the mess.

Jim Lusk said:
See if you can have it dipped. That's the only way to get to the rust in the crevices.
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ch1ll said:
Yes, have it dipped. It won’t cost that much and by the time your done with treating it with whatever, you’ll be ahead money and time wise. Dip it, seal it, repair it and paint it.
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I've been looking into dipping, but unfortunately, I haven't been able to find anywhere within a reasonable drive that can do it. The closest place I've found so far is in Eugene OR (about 7 hrs away). I'll be making more calls on Monday though since I think a lot of places are closed today for the holiday.
 
There are alot of these places, google metal treatment. They are used for machined parts that sit in storage too long before use so its not just an automotive thing.
 
Make sure its phosphate treated after dipping if you go that route to protect it from rust before you get a chance to seal it in epoxy primer. The process of dipping uses electrolysis in a caustic solution.
 
mopowers said:
...I've been looking into dipping, but unfortunately, I haven't been able to find anywhere within a reasonable drive that can do it. The closest place I've found so far is in Eugene OR (about 7 hrs away). I'll be making more calls on Monday though since I think a lot of places are closed today for the holiday.
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$150/panel
 
ch1ll said:
There are alot of these places, google metal treatment. They are used for machined parts that sit in storage too long before use so its not just an automotive thing.
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Thank you. I'll do some more digging. Not sure if you noticed I'm in California though. Those types of businesses are few and far between around my neck of the woods. I called about 10 plating/stripping/body shop places within a couple hours drive today and none of them knew of a shop in Northern California that had the ability to dip something as large as a trunk decklid.

1MeanA said:
$150/panel
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I have separated hoods but they are spot welded, not crimped. I wouldnt attempt to uncrimp a trunk lid. Maybe an experienced body man could do it.
If its just surface rust you can treat it with a phosphoric acid rust converter. Most rust converters on the market are phosphoric acid. I like to use Ospho brand.
You can also pour epoxy primer in there and let it run into all the crevices.
Here are a couple shots of my hood I separated.

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mopowers said:
View attachment 1716009477
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Google search and found this.:

Pricing | Metal Dippin

Pricing | Classic Car Acid Dipping to remove paint &rust
www.metaldipping.com www.metaldipping.com

There used to be a place around here that did that but it closed awhile back. It was a miserable place and I doubt you could even find people to work there these days. I can't see anybody in their right mind getting into that business now especially with the environmental regulations. I expect doing it in California would be even more restrictive.

Also, I have doubts that any process will properly remove rust from a seam. Do the best you can and cross your fingers.
 
1MeanA said:
Google search and found this.:
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There used to be a place around here that did that but it closed awhile back. It was a miserable place and I doubt you could even find people to work there these days. I can't see anybody in their right mind getting into that business now especially with the environmental regulations. I expect doing it in California would be even more restrictive.

Also, I have doubts that any process will properly remove rust from a seam. Do the best you can and cross your fingers.
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Yeah, that's the place I was referring to in Eugene OR. Unfortunately, it's a little far for me. I'll give the acid a try and. I guess it's better than nothing.

Has anyone tried grinding the seam to separate the panels, then welding it back up?
 
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I've peeled a couple of hoods apart without much trouble... This is the product I use...
 
Well, after about 20 more calls today, I'm pretty confident in saying the closest place to have it dipped is about 500 miles away, so that's not happening.

I'll get what I can with some acid and call it good. I don't even want to think about how much time it would take me to grind the crimped seem to separate the panels and try to attach them keeping a decent trunk panel gap.
 
FWIW In most applications I don't have much use for POR15, I've had it peel from metal that had 99& of the rust sanded away leaving clean shiny metal... But POR15 actually sez to apply it over the rust, brush loose rust away then paint... Well, I've done a few decklids with it & it does seal the metal & prevent air & moisture from getting to the surface...

Using conversion coatings that are supposed to convert rust generally need to be neutralized or at least thoroughly rinsed... Kinda hard to be sure you got it all out of a decklid & since the stuff is a form of acid I don't like taking chances...

I the past I've poured 1/2 pint of POR15 into the decklid & rolled it around allowing the paint to spread as much as possible... Let it dry for a few hours then pour the other 1/2 pint in & roll the decklid around some more but this time start rolling the opposite direction... Clean up any POR15 that leaks out before it dries....

BTW wear latex gloves and old clothes while doing this & it's best to do it over the lawn so if any spills you let the grass grow & mow it....

Also as much as you & I both would like to take the decklid apart to clean inside it don't!! You'll never get it apart without destroying it..
 
MoparMike1974 said:
I agree, you would be hard pressed to uncrimp and recrimp a panel without distorting it.
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My dumbass was even considering grinding the edge away to split them, then welding the perimeter to reattach. Nope, screw that! haha!

1WildRT said:
FWIW In most applications I don't have much use for POR15, I've had it peel from metal that had 99& of the rust sanded away leaving clean shiny metal... But POR15 actually sez to apply it over the rust, brush loose rust away then paint... Well, I've done a few decklids with it & it does seal the metal & prevent air & moisture from getting to the surface...

Using conversion coatings that are supposed to convert rust generally need to be neutralized or at least thoroughly rinsed... Kinda hard to be sure you got it all out of a decklid & since the stuff is a form of acid I don't like taking chances...

I the past I've poured 1/2 pint of POR15 into the decklid & rolled it around allowing the paint to spread as much as possible... Let it dry for a few hours then pour the other 1/2 pint in & roll the decklid around some more but this time start rolling the opposite direction... Clean up any POR15 that leaks out before it dries....

BTW wear latex gloves and old clothes while doing this & it's best to do it over the lawn so if any spills you let the grass grow & mow it....

Also as much as you & I both would like to take the decklid apart to clean inside it don't!! You'll never get it apart without destroying it..
Click to expand...

That sounds like a reasonable approach. I figure anything I do will be better than nothing, and even if I do nothing, it'll still be fine for what I'm doing with the car.
 
I would use epoxy primer. Its much thinner than por15 and will easily get all the way into the clevises at the crimped edge.
 
I figured I should go back and update this. I decided to give a citric acid bath a shot and it worked to perfection. I built a frame with some scrap lumber, lined it with several layers of plastic and made a pretty dilute citric acid solution mixed at 30:1 by weight water to citric acid. It took two days, but completely eliminated all hidden rust. Here are the results:

Before:

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During:

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After:

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I'll be using this method again for sure. Here's the acid I bought. A 10lb bag was about $36 and is enough to make 36 gallons at the 30:1 ratio I used.

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Did you have to neutralize the citric acid left over on the panel?

I used a muratic acid bath on some parts a few years ago, and they required a quick dip in water mixed with baking soda to neutralize the acid leftover on the metal.
 
adam83 said:
Did you have to neutralize the citric acid left over on the panel?

I used a muratic acid bath on some parts a few years ago, and they required a quick dip in water mixed with baking soda to neutralize the acid leftover on the metal.
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I just rinsed it off really well with soap and water before it had a chance to dry. The citric acid solution I used was very dilute at 30:1, plus it's a much weaker acid than muriatic acid or the phosphoric acid I normally use. I believe, the pH of those two are around 1-1.5 if I recall and the solution I used was around 3.

Probably not necessary, but I did neutralize the acid before disposing of it though.
 
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