Technical Metal working advice needed

Ok....so I recently cut a section out of my quarter panel to smooth it out in the English wheel. A previous repair had the panel looking like a bag of walnuts. So after smoothing the panel out and welding it back on I had some shrinkage along the weld seam. The front half of the panel was easy to work out with a hammer and dolly...but as you get closer to the wheel well I can’t get a dolly on the backside of the work to stretch the metal back out. I’m looking for recommendations on how I can fix the low seam. I do have access to a stud gun and slide hammer...but I don’t feel like that’s the right solution.

circled in red is the approximate area I’m having issues with. I know some of you have had this problem in the past and know how I can fix it. Thanks in advance for sharing your knowledge with me.

 

I still have a small patch to do on the lower part of the wheel well....that’s why you see the seam clamp close to the wheel.

 

Can you get a spoon in that area?

 

In the pic below you can see how far back the wheel well goes. I can probably get some flat stock behind it to use a a dolly...but it wouldn’t be anything much over a 1/4” thick.

 

stud gun, a long pic tool or pry bar.
I have welded dollies to round stock to reach tight areas
finish up with a shrinking disc
you can avoid this by welding about 3/4 of an inch then hammer and dolly.

 

I don't think I would fight it very long, chop out that little bit and weld in a new patch. I know it's painful once you have it welded up, but honestly an hour and your done.

 

It looks to me like expansion caused the problem. I'd try a shrinking hammer above and below the weld and see if you can't draw it close enough to shape. Other than that I would use a thin cut off wheel and recut where the weld is and the hammer everything as straight as you can. Grind away any overlap and reweld very very slowly.

 

You can use a stud gun to shrink, too.
SPark

 

I had a similar thing happen on a long flat panel I was working where I replaced the lower rocker and had to do one continuous butt weld that introduced a lot of heat into the panel and it ended up "puckering" part inward, part outward. I fixed most of it by hammering the outward pucker flat and checking it with a straight edge but one part I just could not get to draw back in. I ended up cutting it out and replacing it completely but had some success with heating spots with a torch and then quenching them to shrink. A shrinking disc was recommended to me and would have probably worked well but I knew I was going to replace the panel at that point so I never bought one.

One important thing I learned welding that long butt weld was about heat control. It sucks and it takes forever but tacking, quenching, then moving a couple inches and repeating will save this from happening, most of the time. Also grinding your tacks down as you go helps you feel the panel better and line up your next round of tacks. If that panel is readily available and inexpensive I'd just cut it out and do it over.

 

Sometimes its easier to cut out an access inside the wheel well, fix your panel, then weld the piece back in.

Sent from my SM-G973U using The H.A.M.B. mobile app

 

I use a piece of leaf spring for a backup in area's like that. I have a huge anvil too so i can put arch in the spring if u need to to get the right curve in behind the wheel house....

 

If that panel fit without force and had a correct contour, all this damage is a result of welding. If it has shown up after lots of banging it from excessive banging.
Any damage that wasn’t present before welding is caused from welding. Only hammer and dolly work will reverse it.
Cuts and slices will possibly cause more.
When ya slice it, ya got to weld it. Then more distortion. I welded in a section in 59. I got in a hurry and didn’t hammer and dolly as I welded. It distorted similar to yours. I fixed it by hammering. I did use a stud gun to bring the metal out so I could fit a dolly behind it. You may have to make something to fit behind it.
Or cut an access as suggested.
I learned to be more patient and not skip any steps to avoid this large amount of distortion. What time I thought I was saving caused more time overall.

 

I had to do this very thing on my 66 Suburban.

 

if you don't have a dolly that works make one. I have one I made for something I could not get to that would work well on that.

 

You could tack weld a 3” or 4” strip of sheet metal along the lowest area, using the metal strip to clamp onto and pull evenly while hammering the high spots and working the area that’s high around your weld.

 

^^^ Same as a stud gun but cheaper..............

 

Is the vehicle a '55/56 Ford?

 

I do this exact same thing at work all the time pulling rockers and panel corners and edges. When I'm done just cut them off with a die grinder and no one ever knows you were ever there.

 

It’s a 51 Ford sedan

 

I would heat and quench every couple inches and also use a tool to lever out , I have a thin spoon for areas like that .

 

20/20 leave a gap 1/16-1/8" between the panels. When one panel warps it pushes on the other panel. I would use a thin wheel and cut the weld and bend out the metal, stitch weld it a little at a time.

 

Why a gap for sheet metal?

 

Good idea. Several shrinks done one at a time with a helper inside carefully as to not cause stretching out ward driving small areas against a dolly held outside.
Repeat.
You will find that the weld bead will be rigid.

 

Another question. If shrinking from the welding process causes the distortion, why use a torch and continue shrinking?
If the parts starts to sink in during the welding, and that sinking is not corrected, the welding will lock in that sink. Add that to the normal shrinking associated with welding. This plus the fact MIG welds are harder than the parent sheet metal will make for s difficult stretch.(Weld shrink correction)
If welded with the metal already distorted (sunk in) a cut could allow the sunk in area to release.

 

One more observation that may help you on the next one.

It looks like only the outside skin was removed, leaving the factory spot weld lip along the red highlighted area.
That’s a ton of butt welding that adds a lot of potential for distortion and lots of extra grinding.
It you remove the panel in as many factory locations as possible a considerable amount of welding and grinding can be eliminated.
Factory spot welds are simple to remove

 

The outside is what's important. Cut out the inner structure so you can get at it with a dolly.

 

Think you might have been better off repairing the previous damage raising the low spots with some off dolly hammer work and shrinking the high spots. It could not have been that bad if you where able to wheel it out without distorting and stretching it to begin with. Now you have distortion AND a hard ass mig weld to deal with. If the weld has penetrated to the back side , you will need to surface that down as well. I would use a spoon that is close to the panel conture, get a helper to hold it on the back side. Take a torch with a small tip and start at the least damaged part on the weld and heat a 1/2 to 1 inch area and panish the weld "on dolly" with a slapper or hammer and hammer off dolly on the surrounding high spots to lower them. Let that area cool , do not quench it. That will work harden the metal and the weld even more. This is not a beat it to death with a hammer and dolly repair. This is going to be a long drawn out repair. Use lite pressure on the spoon and lite hammer blows . Keep working it little by little to the deepest part of the weld. If you try to raise the deepest part first you will stretch the surrounding metal even worse. Back when they gas welded panels with a torch it was called hammer welding. I have been gas welding for 50 years . mig and tig for 40. Anyone can screw something up ,takes some one with skill to fix it. How do you become skilled? You spend 50 years fixing your screw ups! Wish you luck. Larry