Thread: Fab of bottom door panels for 1937 Buick

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When I was doing rust repair on my 73 charger, I experimented with two techniques which showed promise, maybe MP&C could chime in:

#1 For a patch with no access for planishing, I put an extra bit of crown in the patch. After shrinking, the crown pulls out, effectively preventing the patch from being distorted.

#2 where planishing is accessible, I would put a slight flange on the patch weld seam. During planishing, the flange gets hammered flat, effectively 'stretching' the patch, and compensating for the shrink.

I always say use what works for you. In addition to that, always strive for improvement.

The best I have seen is this "no-filler" fusion weld using a TIG machine in this Buick door link below. Absolutely beautiful work and process. Sorry, but you'll need to be a member to view the attachment pictures. Well worth the effort of signing up, as this is about the best process going for door repairs.


Welding buick door - All MetalShaping

Originally Posted by firebird77clone

When I was doing rust repair on my 73 charger, I experimented with two techniques which showed promise, maybe MP&C could chime in:

#1 For a patch with no access for planishing, I put an extra bit of crown in the patch. After shrinking, the crown pulls out, effectively preventing the patch from being distorted.

#2 where planishing is accessible, I would put a slight flange on the patch weld seam. During planishing, the flange gets hammered flat, effectively 'stretching' the patch, and compensating for the shrink.

In the above link, Richard indicated that he had realized a slight amount of stretch from the serrations of the snips used in cutting the seam. I'm quite sure the edge was touched up with a file to get a perfect seam, but the stretch remained. This slight amount of prestretch was perfect for the MINIMAL amount of shrinking you get with the TIG fusion weld. If it were MIG we would need much more pre-stretch. For your suggestions, I think I would try #1 first, and the amount of stretch needed would be largely determined by the process used. (resulting in trial and error, ie: practice pieces) Anything done in a process should not inflict any more damage to the panel, so I would shy away from the flanging as any creases are more difficult to remove. That's not to say its a "wrong" way to do it, perhaps less preferred due to my perceived notion that it involves extra work. It may in fact require less work, given all the planishing that would be needed otherwise (using MIG). But, referring back to my first statement in this post, use what works for you. And if we're using the MIG, we're dealing with extra work anyhow, let's be honest. If it weren't for you practicing some different methods at the bench in trying to overcome the pitfalls (shrinking from welding) that wouldn't be thrown in the mix as an option. By practicing different methods we find what works the best given the welding process we are using (MIG vs. TIG, filler vs. fusion, etc) The important step for anyone new in the game is understanding what is occurring to be able to make adjustments to deal with any issues. Hence the book I wrote above...

Originally Posted by MP&C

I always say use what works for you. In addition to that, always strive for improvement.

The best I have seen is this "no-filler" fusion weld using a TIG machine in this Buick door link below. Absolutely beautiful work and process. Sorry, but you'll need to be a member to view the attachment pictures. Well worth the effort of signing up, as this is about the best process going for door repairs.


Welding buick door - All MetalShaping







In the above link, Richard indicated that he had realized a slight amount of stretch from the serrations of the snips used in cutting the seam. I'm quite sure the edge was touched up with a file to get a perfect seam, but the stretch remained. This slight amount of prestretch was perfect for the MINIMAL amount of shrinking you get with the TIG fusion weld. If it were MIG we would need much more pre-stretch. For your suggestions, I think I would try #1 first, and the amount of stretch needed would be largely determined by the process used. (resulting in trial and error, ie: practice pieces) Anything done in a process should not inflict any more damage to the panel, so I would shy away from the flanging as any creases are more difficult to remove. That's not to say its a "wrong" way to do it, perhaps less preferred due to my perceived notion that it involves extra work. It may in fact require less work, given all the planishing that would be needed otherwise (using MIG). But, referring back to my first statement in this post, use what works for you. And if we're using the MIG, we're dealing with extra work anyhow, let's be honest. If it weren't for you practicing some different methods at the bench in trying to overcome the pitfalls (shrinking from welding) that wouldn't be thrown in the mix as an option. By practicing different methods we find what works the best given the welding process we are using (MIG vs. TIG, filler vs. fusion, etc) The important step for anyone new in the game is understanding what is occurring to be able to make adjustments to deal with any issues. Hence the book I wrote above...

Thanks Robert. Your detailed descriptions and guidance are very much appreciated. Just signed up on Allmetalshaping.com and will check out your link.
Attached is a picture of the back of the door.
The rust goes about 5 inches up the door. I have bee using butt welds for my repairs.
1) For the door bottom, would I be better off using a flanger and creating an overlapping flange at the top of the 5" panel?

Originally Posted by Mutt's37Buick

Attached is a picture of the back of the door.
The rust goes about 5 inches up the door. I have bee using butt welds for my repairs.
1) For the door bottom, would I be better off using a flanger and creating an overlapping flange at the top of the 5" panel?

If you've been using butt welds thus far, don't stop now. That's the correct method to use. Regardless of the dis-information you can find online regarding using flanges, especially manufacturers selling the flanging tools claiming what an advantage they are for installing panels and the fact that replacement panels come with them, flanges are not a good solution for a sheet metal weld repair.

Sure, flanges can be a crutch for someone who is just learning to weld, but you are adding rust issues/moisture trap, and more importantly the single panel thickness on one side of the weld expands faster in sunlight than two panel thicknesses on the other side. So despite any filler and paint covering the flange seam, the repeated differing expansion and contraction rates will eventually leave a ghost line in your paint finish right at the seam. Just like a wart on the end of a nose, everyone will see it and know exactly where and how the repair was done. Any deformity from the welding process also becomes near impossible to planish out the defects given the multiple layers. IMO is detracts from the value of the car as it is not the correct way to repair. You hear guys saying it's OK to use on floor pans as nobody will see them. I disagree as this is the perfect scenario to practice butt welding to improve your methods, so when you are on a panel that really matters, you feel more comfortable and are more skilled doing it. Keep up with your butt welds...

Originally Posted by firebird77clone

When I was doing rust repair on my 73 charger, I experimented with two techniques which showed promise, maybe MP&C could chime in:

#1 For a patch with no access for planishing, I put an extra bit of crown in the patch. After shrinking, the crown pulls out, effectively preventing the patch from being distorted.

#2 where planishing is accessible, I would put a slight flange on the patch weld seam. During planishing, the flange gets hammered flat, effectively 'stretching' the patch, and compensating for the shrink.

Thanks for your help