Question for the welders/fixers (1 Viewer)

[EStein]

OP, if you're able to get a dolly behind it (along entire weld seam), I'd start with hammer and dolly first, starting with light taps and putting the coals to it as needed, hammering on the crowned side. If you're able to flatten it but end up with it oil canning on you in areas, then you can do some spot shrinking with a single or double 0 tip.
Never used a shrinking disk, so can't comment on it.

This may be of help in understanding weld shrinkage:

IDK if he has a vid on it:
https://www.youtube.com/channel/UCtRedgDFHDnLuBO040NdL1g/videos?view=0&sort=da (...wealth of info and technique here)
but in welding seams like you have with mig, he'll start by tacking it (dotting) about every inch or so.
When cool, go back over every weld dot first with hammer and dolly to planish it, concentrating on just the prouds of each weld. Goal here is to neutralize the 360 degree "pull" around each one.
Follow this up by grinding down whatever peaks are left on each dot, leaving them maybe .010 to .015" proud of your base. And grind both sides if possible, unless you want a ghost line in your finished paint work.
After this is done to all your weld dots, go back and add another dot adjacent to and overlapping your first planished and rough ground dot. Follow this with more planishing and grinding...wash, rinse and repeat until your seam is 100%, then go in and do your final finish grind.

Slow and monotonous yes but being able to planish each weld dot individually makes it much easier IMHO to control weld shrinkage than trying to tackle a full length weld seam after the fact.

Hope this helps and g/l.

I’ll check it out this afternoon….thanks!

 

[peesalot]

Problem with shrink disc IMO is the skin & weld are diff composition and will react differently so you may change the shape but not nec flatten it.
I guarantee to get that flat you will weld holes in the skin(burn thru) thats why I said make a sample of the problem out of scrap, fix that to your satisfaction then apply that method to the piece. I might try preheating with a plumbers torch or give tig a try, if its clamped flat you can fill it nicely with TIG, and when you grind for flat its going to be painfully slow as you literally cant hit one spot long enought o take it down, a typical weld ball will take 4 passes or more, letting cool each time and you can NOT just run the grinder down the line, you have to take each tack down one at a time, when its close to skin go get the flapper wheel. OR you could weld a door bar on the inside so you have a hard straight surface to tack/grind the seam to if a door bar wouldnt block window that might be the best to get it flat & keep it flat.

 

[Malleus]

Too late now, for sure, but a backer piece would have been the way to go. If you cut it and weld it again (my choice), try this method. The thicker the backer the better.

 

[diesellibrarian]

I agree with the person who suggested dollying your weld seam. Welding actually causes metal to shrink. Your seam is raised because the as the weld cools, it tries to gather metal to itself. If you are able to get in behind the seam with some kind of dolly, some serious on-dolly hammering should level things out.

 

[EStein]

I’m on the road for a few days, so I can’t put any of this to practice but I’m a little disheartened. I think the reality is for me to get this flat I would have to be an expert or super lucky… For a second I was thinking screw it. Put in a little overtime and buy a new door. On the other hand, I was half serious when I posted this previously… What if I just cut the whole thing out and kept the new metal as close to the edge as I can… that would help with the warpage. I think this is going to be my last ditch effort if none of these other methods work. I might even have a piece of sheet metal big enough to fit that I got at Home Depot a few years ago. (I’ve heard don’t use Home Depot sheet metal because it is cheap… not sure about that) Anything I’m missing about just replacing the whole panel like in the pic?

Also, all those grinder marks above the seam was me trying to heat the panel up… Then I realized after I was going to have to smooth all that out. Some days you just shouldn’t work in the shop.

Thank you all who have responded. I really appreciate the wisdom.

 

[diesellibrarian]

It would be a shame to do all of that extra work. I really think that some stretching along that weld would make the panel quite presentable. The tricky part will be accessing the back side of the panel to get a dolly in there. It might be easier to cut a few small access holes in the back panel than to cut out half of the door skin and face 8 linear feet of welding to get it back on? Or, if you could work with existing access holes, and somehow attach a dolly to some kind of handle? Or use a long slapper-type tool to reach areas in the middle of the panel? Just spitballing...

 

[EStein]

Yeah, you’re right. I will come off the ledge. I’ll see what I can do first. But last resort I’m cutting that bastard out!

 

[pb4ugo]

I don't see how working around the edges gets rid of the warped/raised seam.

 

[EStein]

I don't see how working around the edges gets rid of the warped/raised seam.

Well, I was thinking because it’s closer to the edge where the metal rounds over its a lot more rigid and less prone to warping. At least that’s how it’s been on my other doors as well as all of the body panels i replaced.
And I go about 10 times slower.

 

[pb4ugo]

Well, I was thinking because it’s closer to the edge where the metal rounds over its a lot more rigid and less prone to warping. At least that’s how it’s been on my other doors as well as all of the body panels i replaced.
And I go about 10 times slower.

I agree, but your warped seam will still be going across the door.

 

[EStein]

I agree, but your warped seam will still be going across the door.

No, that would be cut out. Basically cut out that whole interior that I have outlined.

 

[peesalot]

Could go aircraft style and rivet an aluminum patch over it.

 

[EStein]

Could go aircraft style and rivet an aluminum patch over it.

Haha! Yep

 

[aztoyman]

I say do what YOU feel will work best for your current skill level. If you're feeling it would be better to put a new full sheet on, do it. Especially if it worked on the other door. You can always practice on the piece you cut out later on the work bench.

 

[EStein]

I say do what YOU feel will work best for your current skill level. If you're feeling it would be better to put a new full sheet on, do it. Especially if it worked on the other door. You can always practice on the piece you cut out later on the work bench.

Yeah definitely. I’m gonna mess around with all of the options a little bit. Not gonna stress out over it though. If I have to I’ll just cut it all out. And if that doesn’t work, then I’ll just get a new door. Hell I’ve put so much money into this thing so far what’s another 900 bucks!

 

[brian]

Could have flanged the original joint vs butted it as well.

 

[EStein]

Could have flanged the original joint vs butted it as well.

 

[EStein]

Well, nothing really working. Just making things worse. I’m going to try to cut the seam, but I fear that it will still be warped up toward the middle of where the seam will be. I have a feeling I’m going to end up just cutting the whole panel out and replacing all the sheet metal below the door handle. I’m OK with that.

Question… Would there be any benefit to going with a 14 gauge sheet metal as opposed to 16? Would that help with warpage or should you not mix-and-match different thickness when butting together?

 

[EStein]

Well, I bailed on trying to fix the warping and oil canning. I cut the whole thing out and bought a new piece of metal and replaced all of it below the door handle. Spent about seven hours, welding and grinding. I went extremely slow. I think it’s gonna work. Here’s what I did and thanks for the suggestions to all who responded.

Changed out my wire to the lighter .023. Also turned the heat up on the welder. Made a big difference and it pooled better and made for a lower weld to have to grind later.
Slowed way down. This took most of the day.
I blew compressed air on every single stitch. Probably overkill but I wasn’t taking chances.
I ground some of the weld as I went.
I never did more than two welds together at a time. And then moved at least 6 inches away for the next one. Blowing compressed air in between. I made sure this baby stayed cool!

Somehow, I’ve been able to get away with sloppy welding up to this point. The door was a big challenge and I learned a lot. Thank you again to all who responded to this thread and helped me out. Still a little grinding to go. It’s not perfect but I’m going to be happy with it.

 

[Jim S.]

Looks good! Well done.