55.2-59 1957 Stepside Bedside help needed

[Oldtruckwelder]

I’ve got a pair of bedsides that definitely needs the forums help.
Years back i added new bedside strips with plug welds and new strip of metal to fix rot. Covered them in rattle can primer to protect and stored them.
Recently got them out to prep for epoxy primer and bodywork.
Checking closer with straight edge found both panels had large high spot with tight oil canning… I assume from weight of fender hanging lots of years and possibly stretching metal. For a test I bolted one of the fenders on and it captures the oil canning but doesn’t fix problems..
Marked some pictures to try explain it better.. not sure where to begin.
Need you advice please
Thanks
JT from SC

[leegreen]

The fender would not stretch the metal, bend the panel perhaps but not stretch the center of panel.

There was no welding/heating except plug welds and where you indicate new metal? The overall panel is straight/flat if sighted along the edges with fender off, no twists or kinks?
Then the most likely cause is that the surface has shrunk related to the welding and the most likely location is at the corner of the welded in section. I know that oil can does not seem close to the weld, but I'd start by doing a bit of hammer on dolly work along the weld to re-stretch that metal, stopping to check oil can as you go.
If that starts to make a local bump where you are hammering stop.

If you find that stretching the weld does not help and you want to shrink the high spot, I'd try heat shrinking. Heat a small spot to dull red and the surface tension of the panel will force the metal back into itself at the softened spot. keep the panel overall cool, do small spots and check progress.

You may need to cut the plug welds on bed strip if the panel starts to twist as it gets flatter

[Oldtruckwelder]

Originally Posted by leegreen

The fender would not stretch the metal, bend the panel perhaps but not stretch the center of panel.

There was no welding/heating except plug welds yand where you indicate new metal? The overall panel is straight/flat if sighted along the edges with fender off, no twists or kinks?
Then the most likely cause is that the surface has shrunk related to the welding and the most likely location is at the corner of the welded in section. I know that oil can does not seem close to the weld, but I'd start by doing a bit of hammer on dolly work along the weld to re-stretch that metal, stopping to check oil can as you go.
If that starts to make a local bump where you are hammering stop.

If you find that stretching the weld does not help and you want to shrink the high spot, I'd try heat shrinking. Heat a small spot to dull red and the surface tension of the panel will force the metal back into itself at the softened spot. keep the panel overall cool, do small spots and check progress.

You may need to cut the plug welds on bed strip if the panel starts to twist as it gets flatter

Thank you
I will start planishing around the weld zone and see what happens.
The oddity is that both panels have the oil canning in same location yet the weld zone is lots further away.
I also have a Harris #2 tip for the torch coming through the mail system and will give it a try on some scrap.
Thanks for your help
JT from SC

[SideStepper]

The original OEM bed side panels (prior to assembly, when unsupported) did flex & did oil can. The fact that bedside strips were welded onto your panels leaves a big unknow warping condition factor. I can tell you that I reused my original OEM bed side panels (unwelded) when restoring my 55.2 truck & after fender assembly (with OEM fender rod supports, 3 per fender) the side panels were solid & straight as expected for a 1955 farm truck.

[Oldtruckwelder]

Originally Posted by SideStepper

The original OEM bed side panels (prior to assembly, when unsupported) did flex & did oil can. The fact that bedside strips were welded onto your panels leaves a big unknow warping condition factor. I can tell you that I reused my original OEM bed side panels (unwelded) when restoring my 55.2 truck & after fender assembly (with OEM fender rod supports, 3 per fender) the side panels were solid & straight as expected for a 1955 farm truck.

Thanks

[dsraven]

here is a video on heat shrinking if you need to. oxy/acetylene is the preferred heat source as propane torches heat up a larger area.
https://youtu.be/EBcfhaNwg4Q?si=_-6-NYE9g2wJ0U8H
here is another. this guy has a few interesting videos. japhands customs or make it custom, same guy.
https://youtu.be/M3-WBYm3L_M?si=g1OEeDyHlT4iDEHa

[Oldtruckwelder]

Originally Posted by dsraven

here is a video on heat shrinking if you need to. oxy/acetylene is the preferred heat source as propane torches heat up a larger area.
https://youtu.be/EBcfhaNwg4Q?si=_-6-NYE9g2wJ0U8H
here is another. this guy has a few interesting videos. japhands customs or make it custom, same guy.
https://youtu.be/M3-WBYm3L_M?si=g1OEeDyHlT4iDEHa

Thanks for sharing the links

[leegreen]

>The oddity is that both panels have the oil canning in same location yet the weld zone is lots further away.

I can't tell exactly where the welds are, but the bead rolling may force the metal movement out into the panel. Think of the panel like a sheet of stiff cloth. The bead rolling is like a weight sitting on the fabric, the folded over edges of the bedside are like stiffened edges. The weld is like you pluck the fabric up at that point. where do the wrinkles appear?
If there were any preexisting stresses in the panel like dents, creases before the welding they would interact with the weld shrinking. The bottom corner of the bedside where two folded over edges meet is a point where stresses will tend to aggregate and twist the panel.

hammer on dolly or heat, just go slowly and see how it reacts

[leegreen]

My '52 bedsides well rusted. I ended up cutting the top part off and welding on~18" of new metal full length. On one end of one panel after I plug welded the stake pockets on I ended up with some oil canning trapped into the corner and worked it out with heat shrinking, then careful hammer work.

welds are the red lines/dots

[Oldtruckwelder]

Thank you dsraven
Thank you LeeGreen
Nice work on your bedside

[dsraven]

since it is oil canning around the end of the bead rolling it seems like that rolled area is smaller than the area ahead of the beads. this is actually understandable if you think about the metal moving as the beads are rolled. for a deep bead like that the sheet is normally rolled in an english wheel first in order to stretch that metal so there is enough metal in the area to go where it need to when the beads are formed. if you think of a line from point A to point B it is a certain length. now if you draw another line next to it with a bump out in the middle of that line then the length of the second line will obviously be longer. same kind of theory for the sheet metal when it is bead rolled, it takes more metal in the area of the bead and if the area isn't stretched first the the area around the ends of the beads will have the oil can because the beaded area has basically been shrunk. when I roll a bead I like to relieve the ends of the beads with what looks like a piece of pipe with one side ground off. it makes a C shape around the end of the bead and this seems to help. then some shrinking of the oil can area after is sometimes needed. i doubt if GM did anything other than stamping the profile of the bead and relied on the fender to keep the panel straight.
this video kind of explains the reasons for stretching the metal prior to bead rolling
https://youtu.be/bjA0M5B5BUU?si=zIibIN6gPcDf-3wB

[dsraven]

lazze metal dreams has many videos for sheet metal tips and tricks. this one also talks about the bead roll shrinking/stretching theory.
I think if it were my box sides I would try the "half pipe punch" around the ends of the bead rolled area to capture the stretched area and then shrink the area where the oil canning is happening. I use a shrinking disc for some of that kinda stuff but the torch method also works pretty well
here is a video from wray shelen that shows how a shrinking disc works. basically the disc is rubbed over the panel and hits the high spots, which heats those spots, and then the area is quickly cooled and the hot spots, being hotter than the area around then, cool and shrink quicker than the other areas that were missed byt the wheel. some guys have had luck using a laundry iron set on high to accomplish the same thing with small areas.
https://youtu.be/IGuc06GMwG4?si=lWZsjhKCugYJ-k4c

[dsraven]

sorry, forgot to post the link to lazze. this one is a 2 part one but explains the issue. you could watch part 2 if desired, or other of his videos. they are o youtube if you search it
https://youtu.be/3XBxVtocDqc?si=ZS6ldlzOP708N4qf