Weld Help- shrinking/stretching (1 Viewer)

[Hoperichb]

Looking for a bit of expert help. Welded in some patches this weekend on my 40 tub and have some curling going on now in the wheel well. It appears to have shrunk and created an indention but guessing the heat from the grinder stretched this out at the wheel well. Any tips on this would be greatly appreciated. Is this possible to get back to normal? Hoping maybe @Gusb can help out as I have been watching his thread.

 

[Malleus]

That sheet is pretty thin. If the heat from grinding really deformed it, a little judicious warming from the back side will solve the problem. We used to straighten structural steel this way. A little heat, a little cold water, and you can get metal moving fast enough to see it move.

 

[Prairie Swamp]

Metal shrinking disc. Magic.

 

[kulangot]

Ron Covell and Ron Fournier cover this in their books and videos. I highly recommend them. I search "oil can dent" on youtube and found these: ron covell oil can dent - YouTube it's not just the griding hear that you need to control and the welding heat. Don't put more than a tic tac sized bead at a time. Running a bead on sheet metal is going to make it warp fast!

 

[Hoperichb]

Thanks guys. I tried some targeted heat and cooling without much relief. Need to educate myself on if I should be going to the new metal section where presumably I added too much heat before, above (where the wheel wells connect to the bedside) or below.

I need to use the references you listed and take another shot this weekend. Will keep you updated on progress.

 

[rkymtnflyfisher]

I would cut that patch out and start over. I made the same mistake on my build on one of the first patches I did on the exact same spot.

Slow down between tacks, make sure you START with a nice straight section to work with, you can't weld a flat panel into a warped panel and expect it to come out straight. Did you back up your weld with a heat sink of some sort? Something to help draw the heat from the weld and away from your work, it also helps keep your gas where you are working. Tack a spot about every 4-6" all the way around your weld area and go drink a beer, call a friend, eat some ice cream, or smack some ass. Let it cool. Come back and repeat. Heat is your enemy.

There is a ton of info about halfway through my build thread that may help you out.

 

[Hoperichb]

I would cut that patch out and start over. I made the same mistake on my build on one of the first patches I did on the exact same spot.

Slow down between tacks, make sure you START with a nice straight section to work with, you can't weld a flat panel into a warped panel and expect it to come out straight. Did you back up your weld with a heat sink of some sort? Something to help draw the heat from the weld and away from your work, it also helps keep your gas where you are working. Tack a spot about every 4-6" all the way around your weld area and go drink a beer, call a friend, eat some ice cream, or smack some ass. Let it cool. Come back and repeat. Heat is your enemy.

There is a ton of info about halfway through my build thread that may help you out.

Good info in your build thread. This should help my technique. I picked up a 2” copper end cap to backup my welds also and seems to help.

 

[Hoperichb]

I was able to get one side back to where it should be. Hammer and dolly when it was hot and you could see it shrinking back in. I haven’t tried the other side but think I’ll just cut it out and re do as it is in a pretty easy place to get to. Thanks for the help guys.

 

[morganism]

Thanks for the tip on oilcanning on utube.

am lusting over these copper backs now

https://www.amazon.com/Durston-Manu...rd_wg=CH9ce&psc=1&refRID=J39FKC88QS7XDF1E3VPR