Roof Sheet Metal

[Doppleganger]

Ok, so I had the cab soda blasted. He does not touch roofs for warpage reasons so roof is still in original paint. Roof was dirty so I'm wiping it down - looking things over for a sand/primer soon. I cant believe how thin and cheesy the sheet metal on the roof is. I notice there is a slight ripple. Cant see it at 10ft (sits so high you wouldn't see it anyways) but up close and on an angle, you see it good - especially when its up against a straight reflection. They aren't dents - more like sags. Real soft and pliable. I suppose one could put a skim coat of filler on it and block sand it, but this stuff is so soft, I dont know how you could. Almost wish they had put foam or something between the layers to stiffen it up. Talk about a pop can.

Anyone dealt with this, and if so, how?

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[bucket]

That's actually from people (or something) sitting on the roof. If you can use a self-welding dent puller or a stud gun, carefully and methodically pull out the low areas so that the roof skin will get it's crown back and regain it's strength. If using a stud gun, you will have to do the process several times and will require a lot of studs.

 

[Doppleganger]

That's actually from people (or something) sitting on the roof. If you can use a self-welding dent puller or a stud gun, carefully and methodically pull out the low areas so that the roof skin will get it's crown back and regain it's strength. If using a stud gun, you will have to do the process several times and will require a lot of studs.

I have a good idea how it happened.....involves blasting the bottom (which I told them not to do - was clean factory primer - so wasn't necessary). I think they pulled it on that top section to lay it down. My theory anyways.

The whole area is like whack a mole - push one area down, it pops up the next section over - push that down, same thing. Oil canning I think is the term? There's about 3-4 'sections'. Metal feels really soft too. I have a self welding stud gun - just wasn't sure that would work if the metal was stretched.

THX

 

[bucket]

I have a good idea how it happened.....involves blasting the bottom (which I told them not to do - was clean factory primer - so wasn't necessary). I think they pulled it on that top section to lay it down. My theory anyways.

The whole area is like whack a mole - push one area down, it pops up the next section over - push that down, same thing. Oil canning I think is the term? There's about 3-4 'sections'. Metal feels really soft too. I have a self welding stud gun - just wasn't sure that would work if the metal was stretched.

THX

Yep, "oil canned".

The roof, in proper shape, has a slight crown in all directions. With those depressions, the roof is basically flatter and there's too much metal for a flat roof. Getting the steel worked back up will essentially 'shrink' the roof skin. Having those depressions now has in fact stretched the metal very slightly, but the heat from the studs will help take care of that.

The key is to work carefully. You don't want to move any one part of the skin too much at once. It will seem like you aren't doing much, and that is good. After a long period of not doing much, it will all add up to a roof skin that has a proper contour and is not stretched.

 

[1STLS1]

There isn't a simple solution. If using the stud gun, cool the area immediately to shrink it. Pull up and tap around it down. Another thing I had done with tin canning is get it as good as it will get and run a bead of urethane on the inside to hold it in place. Works on hoods and doors too. It's getting covered by a headliner, door panel or hood blanket, sometimes that is all you can do.

 

[Doppleganger]

I cant see how the original shape could ever be recovered. Unless I win a lottery and could have someone who knows what they're doing fix this, this is about the end of the whole mess for me.

Thanks fellas.

 

[bucket]

I cant see how the original shape could ever be recovered. Unless I win a lottery and could have someone who knows what they're doing fix this, this is about the end of the whole mess for me.

Thanks fellas.

It just takes patience It can be repaired with an extremely minimal amount of filler after it's been metal finished.

 

[Doppleganger]

I wonder how involved it would be to swap out a new roof skin?

 

[CalSgt]

I wonder how involved it would be to swap out a new roof skin?

My 2 cents, More work than fixing what you've got...

 

[DanMcG]

That's going to be a lot of work to fix, the metal is stretched and you'll need to shrink it back with a stud gun and a hammer like mentioned above.
AMD offers a roof section now, but I can't imagine replacing one. I guess you could use a new roof to make a patch panel, but that would give ya a whole new set of possible warpage to deal with.

 

[Doppleganger]

I've never done this and have no idea how not to make it worse, or worth even less if its parted out. For me to have any chance at finishing this truck, the cab had to be in paint before winter so I could start reassembling / wiring it over the winter. No idea what a real body shop would want to fix this - or the way this area is, if they even know what oil canning is (seriously). Any vids always shows them fixing an issue with access to both sides.

I'm going to show the pics to the guy who stripped it - for whatever thats worth. We need to move but cant with this unfinished mess that will not go away. Thing is worse than a boat.

Sorry for the venting. Wife and I have talked seriously about unloading the whole project if it cant be finished in a decent time. Sht like this doesn't help.

 

[Doppleganger]

That's actually from people (or something) sitting on the roof. If you can use a self-welding dent puller or a stud gun, carefully and methodically pull out the low areas so that the roof skin will get it's crown back and regain it's strength. If using a stud gun, you will have to do the process several times and will require a lot of studs.

Is welding the studs necessary or can you just use it for the heat? I saw a short vid of a guy using just a stud welder and then drenching it with cold water. Did this a dozen times for a small area. Most all these vids are on doors where both sides are accessible, or they are much smaller areas - mine is about 12" x 40". What about a torch?

At this point I have nothing to lose to try it - just dont want to make it worse.

THX Andy.

 

[waterpirate]

I feel your pain.
Shrinking metal and moving it around is an art form. Most new body guys don't get it. Panel changers and glue experts is where the industry has gotten to. The older guys who know how to use all the body hammers in their tool box is who you are looking for. As a fall back position, you could dimple it with the pointy end of the body hammer and fill it. I would suggest that route rather than trying a roof replacement.
Eric

 

[hoagster]

I have a couple of spots like that on mine and they are butt prints from high school days gonna leave them! They make a shrinking disk that heats up the metal and then you cool it, but like everyone else if you have to be careful not to make it worse!

 

[Doppleganger]

I feel your pain.
Shrinking metal and moving it around is an art form. Most new body guys don't get it. Panel changers and glue experts is where the industry has gotten to. The older guys who know how to use all the body hammers in their tool box is who you are looking for. As a fall back position, you could dimple it with the pointy end of the body hammer and fill it. I would suggest that route rather than trying a roof replacement.
Eric

Replacement is out of the question...AMD is out of stock and the cost would be worse. Torch and a pointy body hammer is how I've seen it done the most. I guess an acetalene is better than a propane. Dunno, but I only have the latter. One route I will try if the other doesn't work out.

Also have another theory as to how this happened....the cab sits so high even on the dolly that you cant see the top. I am wondering if the open wind from the drive affected the back half of the roof through the interior light hole. This sheet metal is so thin, doubt it would take much.