Metal help

texasking

Promoted Users
What would the metal gurus on here do about this? All the sharpie lines are low from blasting, I assume. I'm getting ready to get the torch out, again:)
 

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Chris_Hamilton

Trying to be the best me, I can be
Robert's the Guru, but I've got a big mouth so this is my take.
I've had success with this method. Might take some trial and error but if you can access them from the backside push a low spot up, get the torch (small tip, neutral flame) and heat a small spot in the center of the low spot. Dull red is good enough. First couple I would try that and let it cool on its own. Might need to do it in several areas of the low spot. Also when you push it up , run your hand and see if you can feel a high. That would be the place to start.
If that doesn't shrink it enough heat a spot and tap with body hammer. If it's floppy you may have to support it with a dolly on the backside, but don't hit it hard enough to ring the dolly. I wouldn't artificially cool it (air or wet rag) as it will get harder to work that way. Go slow, don't get in a hurry....you know the drill.:)
 

MP&C

Member
Agree with Chris…

1. Is this a trunk lid
2. Do the "low spots" match up to holes in the inner structure on the back side..
 

MP&C

Member
The reason I ask about the inner structure, is most of the time, damage such as this follows those openings exactly, and kinda verify that it was indeed sandblast damage. Someone is blasting along cleaning up the inside oblivious to the fact that nothing is hitting the panel underneath that brace, only at the opening. The peening action starts the stretch on the same side that the media hits, so it stretches INWARD toward the media source.

For heating methods, Robert kinda shys away from torches for sheet metal shrinking because I like the slower sneak up on the fix approach. Faster methods tend to have me sliding past the exit ramp sideways, and then I need to stretch again. So here is a media blasting damage "study" I did, and various methods to correct.

http://67-72chevytrucks.com/vboard/showthread.php?t=647269

My preferred method is using the heating tip on a dent puller, trunk lid upside-down so we have peaks upward, and then use the heating tip on the high(est) spot. By shrinking while the weight of the dent puller is against the panel (but don't push, you won't need excessive force) you can actually see the panel move down/outward as the shrink occurs. So in the same way that Chris is pushing a low outward and then heat, both are persuading the panel to move in the direction to remove the low even before heat is applied. But it boils down to using the "shrinking" tool you have, and what works best for you.

The panel really doesn't care which side heat is applied, it will shrink regardless. But in my experience, just having that little bit of force (weight) against the inside, it seemed to restore proper panel crown more quickly.
 

texasking

Promoted Users
Agree with Chris…

1. Is this a trunk lid
2. Do the "low spots" match up to holes in the inner structure on the back side..
It is a trunk lid on a '67 Nova. All the lows are in the areas where the inner structure is not touching the outer skin. The problem with this particular trunk lid is there is very little access to the outer skin, only small holes. I worked on it this afternoon for a couple hours and got it 90% of where I want it to be by using the torch and working it very gently with low heat. I will see how it looks in the morning and try to get it a little closer without overshrinking. Right now it is sturdy and not trying to oil can, so I hope it is pretty close. I always read, with great interest, the posts about some of the fantastic metal work that is done on this forum. I am in no way even in the same league as some of you, but I have learned a lot and am getting pretty good at fixing these "blast" damaged panels, thanks to many on this forum.
 
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