Tig welding can be a better choice in our rust repair endeavors, providing we can get a good fitup. Next step would be to tack from one end of the panel to the other to hold things in check as you make that long weld pass. Here's a video we did last night to show our tacking method.. The electrode was moved side to side over the seam to EXACTLY locate the seam, then raised for the tack.
Thanks for sharing the video. Now that I am completely done with all of the sheet metal welding that I will ever likely do, I can now rest, knowing how I should have done it. BTW, I would suggest avoid making any "long weld passes" on sheet metal with TIG or MIG. Your formerly calm sea smooth panel will end up looking like the angry sea on "Deadliest Catch" day. Carl
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
I would agree on the long passes with MIG as that would be close to impossible, but with the TIG or O/A gas welding, a full weld pass with no gaps should eliminate much of the distortion realized providing the panels were tacked first to hold things.. Of course, all this assumes weld placement in a good panel is not in the flat low crown area of a door, etc. There's no shape there to help hold things, and things ARE going to move. Weld placement should be based on accessibility for planishing and panel details to help hold things from getting carried away (bend lines, bead details, etc)
We'll video the next step after tacking this evening..
If you can run a full weld pass on flat 18 gauge with a TIG without significant warping, you are the man. I can't wait to see the video. I am still impressed with the video showing the high amp quick zap for the tack welds. While that notion crossed my mind when I was overheating my panels with a lower amp setting, I never had the stones to experiment with it.
Last edited by 52Carl; 12/02/20162:51 AM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
I've seen several body men on Okinawa do a continuous pass with a needle-sharp acetylene flame on body metal with virtually no distortion and no fill rod- - - -just butt-weld the seam together on a tightly-fitted patch panel. It was a real education! I can do it, but not as neatly as some of those guys did! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
If you can run a full weld pass on flat 18 gauge with a TIG without significant warping, you are the man. I can't wait to see the video. I am still impressed with the video showing the high amp quick zap for the tack welds. While that notion crossed my mind when I was overheating my panels with a lower amp setting, I never had the stones to experiment with it.
Carl, think of your speed as a heat control. By using the lower heat setting you are possibly sitting there longer and widening the Heat Affected Zone. The welds I did this evening still had the machine set at 70 amps, and used a faster torch travel to control realized heat at the panel. HAZ was relatively narrow. Next, starting and stopping, regardless of the process, is where you see most distortion added. So if we can use a process that is more user friendly to a full weld pass (TIG or O/A) we can eliminate another source of distortion....
Here's the pictures of the TIG welds... As shown in the link, the trick to the full pass welds with TIG is initial tacking but more importantly, to use body features that will minimize or help control the distortion. Sure, a low crown area of a door skin is going to be the worst. Pick a spot up high on the door and now the higher crown of this area helps to control distortion more than the low crown below. Find an area adjacent to a beltline bead detail and it helps even more. Become more selective about where you put the weld seams for panel repair and it will help control all that distortion.
