Problems patching a 1/4 panel

[cuda guy]

Ok guy,

I gotta real problem and I really could use some help.
I'm trying to do a patch repair on my 72 demon on the passenger front 1/4 panel. Today I fit the patch in. Lined it up everything was perfectly lined up.
I tacked it up with my mig set at power level 1 feed speed 2.5 gas at 10 psi and .03 wire.
When I check the patch the metal pulled in really badly so I now have a 1/4 inch indent.
What should I do. What did I do wrong.
I understand the metal will move a certain way when heated but who do u stop this from happening.
Should I just finish tacking it in and than fill it with fibreglass reinforsed bondo and pray.
Please help.

Rick

 

[FISHBREATH]

Did you just tack it or try to weld a bead? I take it that you are doing a butt joint?

 

[cuda guy]

Hi

I was tacking it in butt welded with spacers to line everything up.

 

[green1]

Pound it out. Then use .024, lower heat. Weld just a quick spot at a time, then wet rag. Move all over it, not same place each time. The grinder will warp it too, unless move and slow. On mine, I pop riveted a 1/8" x 1" strip to the back, as a backer, and heat sink.

 

[cuda guy]

Hi

I can't reach it to pound it out, so I was thinking about drilling a couple of holes and pulling it

 

[ramenth]

How much have you gotten done so far? If you've just tacked it in there with no real strong welds, cut the tacks and pull it back out. That'll give you some room to do some metal shaping. If you've got something more solid going on might not be a bad idea to take the cut off wheel to it and do it again.

You're using .030" wire? Go slow. Don't rush. Allow the tacks and the metal to cool almost completely before moving on. Run a bead at one end, go to the other, come back to the middle, then back and forth. Slowly.

I do have to ask the question, though, if you're using gas, why are you using .030"? .024" is half the price and easier to work with on thinner gauge sheetmetal.

 

[66 Dartman]

Tack a washer in the low spot pull it out with a slide hammer then if you can get a dolly in behind it use a shrinking hammer to get it back in shape
If that don't work try a spoon on the inside to pry it out and finish off with a shrinking hammer. just a thought. need some pic's so i can see it lol.