How to straighten panel

[ryans69chevy]

The panel looks worse than what it is after putting a 2x4 along side it. I would still like to know how to straighten it. This is a header panel for a 67-72 wood box. I need to cut out all the rust which is where the wood lays on the lip, but before I do that I feel that it's best to straighten it all out before I cut and reweld.

Thanks

[ryans69chevy]

Here is where the dent is which pulled the back part of the panel towards the dent. Hope that makes sense? I know I have to remove the dent, just not sure that that would solve the issue.

[ryans69chevy]

Hopefully you can tell where the dent is that I'm looking at and where the panel is bent. Like I said it looks worse than what the 2x4 is showing which is a little strange. I just would like it to be as straight as I can get it so when it's next to the cab it looks good!

[MP&C]

Round pipe or solid steel rod that is snug inside the hole, and drive it past the dent to bring it up. Or perhaps some all thread and opposing inserts that have sloped ends that will force each other outward as the all thread is tightened. Not sure how thick the metal is, but perhaps a dent puller using welded on studs, or welded on washer as anchor...

[mongocanfly]

i really wouldnt trust a 2x4 for a straight edge...you could drill a hole in the front of the panel opposite the dent and use a round ended punch thru the hole to knock the dent back out...just lay "face down" on a hard surface..working slowly and moving around the dent you could get most of it knocked back out..weld hole back up when done...for the bow thats in it, I have layed 2x4s on top of bowed panels and just stood on it and bounced a little..a little goes along way though..
I've used a dent riser to remove dents in gun barrels before...very similar to what mpc described...2 wedge shaped pieces of round stock pulled against each other with allthread...works great
mpc is a master metal man so what he says is all good..

[MARTINSR]

You can use a MIG to spot weld a stud or flat piece of metal into that low spot, at the very BOTTOM of that low spot, pull it out so the dent isn't holding the whole thing in, that dent is VERY strong so it needs to be "relieved" of that by pulling just the dent out.

Then lay the panel on the ground with a 2x4 wood board at each end to hold it up, then a 2x4 on top of that area to strike with a 4lb or so sledge hammer nice and easy and that bow would come out.

Here is an article on the subject where you weld a metal tab and pull it.

http://autobodystore.com/forum/showt...ck&=pogo+stick

With yours, that panel is so long and it's not bolted on, you could actually use IT as the "pogo stick" in the article. Put the panel standing up against something like a fence pole or a wall or something and hook the chain that is hooked to your vice grip holding the plate you have welded to the BOTTOM of that dent. Pull back on the top of the panel with the bottom of the panel up against the pole or wall and you can pull that dent out.

Hope fully this makes sense, it sounds kinda goofy I know.

You could also drill a hole in the back side of that panel behind the dent...ahhhhh, that may be a better way to do it. Drill a hole, then using a long drift punch so you can get through the hole down to the dent and push it out by hitting on the drift bunch with a hammer. After getting that dent out so it's relieving the pressure you can go back to the idea of setting it on two strips of 2x4 and striking the back with a hammer on another piece of 2x4. Then weld the hole up that you drilled for access.

I am thinking that would be better than welding a tab on.

Brian

[mongocanfly]

I've also used a cutting disc to cut out a section like where the dent is and either hammer out the dent of the piece you cut out and weld the piece back in or cut a section from a donor piece to replace what you cut out and weld back in....

I've got a po welded up mess on a IH stepside bed rail I'm working on now where I'm gonna cut out a section and just replace it because of what the po did...I'm shortening the bed from lwb to swb so that's generating me a donor piece to replace what they did...

cutting out that bent section would allow the panel to flatten back out...maybe without any hammering...clamp the panel to a strait edge and weld new piece back in....

between martin and mpc they are master's at what they do... I'm just using redneck problem solving so my ideas arnt always the proper/best way to do stuff...I'm by no means a pro..

[ryans69chevy]

Wow! I can't believe it's that simple! I figured this was gonna be a real bugger to fix. Glad to hear it's this easy! Thanks for all the ideas to try!

[ryans69chevy]

Bringing back this thread with an update as well as more questions about this same panel (header panel for wood bed).

I did fix these dents that I had. I tried using my stud welder and pulling - that wasn't strong enough. I then welded a bolt with washer on it and pried up - that still didn't do it.
I finally just decided to cut out small sections from the back on the panel big enough to get a chisel in there and began straightening it out. Welded it back together and we are golden!

I then used my cab as weight and slid my panel underneath it and pried up little by little until the top of panel was straight.

I still have a bow throughout the whole length of the panel more towards the bottom where the wood lays. Should I cut a couple slits in the lip to try and force it to straighten out? Or how would you guys go about this?

[ryans69chevy]

That last picture is showing the backside of the panel towards the bottom where the GM factory indent is. Hopefully you can see that it's bowed.

This picture shows the back of the lip (the lip meaning where the wood lays). Again this shows where the panel is bowed.

Would it work to cut slits in the lip and try and straighten it or is there an easier method that I don't see?

Thanks for any advise!

[mongocanfly]

thing about cutting slits in that lip is it'll only move where you cut it...meaning it'll be a mess if you do...if you know someone with a shrinker/ stretcher you might can stretch the lip and straighten it out...if not a arbor press or similar form of pressure applied gently right on the 90d bend may stretch it back.....but I wouldn't cut it. ....
have you put a straight edge on it to see how much bow it has?
you might could clamp it to a heavy piece of angle iron and gently heat it with a torch to let it relax....but that'd be last resort..

[MARTINSR]

You can heat and cool that area with a torch to shrink it too. Start small and heat JUST the "lip." THUS the reason why you don't cool welds when you are welding, it WILL shrink the surrounding metal.

Brian

[MP&C]

The problem here is that the panel has shrunk from the weld process, NO MORE SHRINKING NEEDED.

Look at the panel "inset", specifically the bends at yellow and blue arrow. If the panel were to lay flat, as per original stamping, the length along these two bends would be identical. From where the weld is placed, left green arrow, the heat is going to cause the lower bend, blue arrow, to shrink. Shrink any flange and the opposite side bows upward, exactly as is shown here.

Next, look at the two green arrows and compare the left (weld) with the right (bend). The welded arrow shows the majority of the bow is at the weld, not the bend. Fix the problem, not the reaction. Any slight bow at the bottom bend is due to the weld and HAZ bowing and pulling the bottom bend along for the ride. Fix the weld problem, leave the bottom bend alone. Trying to notch something at this point will not remove the bow at the weld, and you'll have an oil-canned, puckered up mess.

Your correction method should be to planish the weld and heat affected zone as needed to remove the bow. I.E: When the length along the bend at the blue arrow has been restored (stretched) to its original length matching the bend at the yellow arrow, the panel should be flat once again.

[mongocanfly]

If Robert says it id believe it...I didn't even see the bow he's talking about...I only saw the one at the bend....

[MARTINSR]

OH DEAR GOD, Great catch there MP&C! OMG I hope Ryan didn't go out there heating it with a torch like I suggested!

RYAN! READ MP&C's POST!!!!

Brian

[ryans69chevy]

Thank you guys for the advice this really helps me out!

It would be nice to know how I did this since I took my time and tried to let the panel cool to the touch before welding another pass is dots. If you guys have ideas tell me straight up! I wonder if it cooled too rapidly since I welded this in the winter months. I had my garage heated, but I bet it was only 20-30 degrees F in there. Maybe I shouldn't weld when it's that cold in the garage? I also welded at that location of the panel since the rust was crawling up that far. I figured it would be easier to finish off if I welded there instead of cutting the line made from the GM insert. Am I correct in thinking that or would you guys have cut closer to the insert line?

Brian, no need to worry! I didn't start any repairs on this panel yet.

Greg, the first pic I posted was trying to show what Robert was talking about. When I reread my post with that pic I guess I didn't explain it very good, my bad. I thought I wrote that in there!

Robert, if you wouldn't mind clarifying the steps I need to take to repair this. I've read through a bunch of your threads on here as well as the garage forum and what I've learned is that planishing is taking a grinding disc and grinding down a majority of the weld. Maybe that actually isn't what planishing is? :/ the welds are all ground smooth so I'm not sure how to planish them? Am I suppose to planish the weld where I shrunk the metal by green arrow or planish by the blue arrow?

[MARTINSR]

"Planishing" is striking the metal with a dolly under it so you are thinning the metal by smashing it with the hammer with it on the dolly. Of course try "planishing" is probably more like "flattening" the metal but if you do it "on dolly" (striking the right on the dolly hard with the metal over it) is going to thin the metal.

Brian

[ryans69chevy]

Originally Posted by MARTINSR

"Planishing" is striking the metal with a dolly under it so you are thinning the metal by smashing it with the hammer with it on the dolly. Of course try "planishing" is probably more like "flattening" the metal but if you do it "on dolly" (striking the right on the dolly hard with the metal over it) is going to thin the metal.

Brian

Okay so it's just the hammer on dolly method! I gotcha. That should be easy enough to do. Patience is the name of the game with this stuff.

So am I suppose to use the hammer on dolly method where the green arrow is or down the panel more where the blue arrow is?

[MP&C]

The shrinking takes place primarily at the weld, and also at a lesser extent in the HAZ area, which can be identified by the discoloration to either side of the weld. This is where the shrinking occurred, this is where the planishing/stretching needs to occur, respectively.. more directly on the weld

[ryans69chevy]

Robert,

That makes perfect sense. I will give it a shot one of these days and report back.

Thanks!