butt weld with tig techniques

[theKbStockpiler]

Hi, I can't find too much on this with a web search if the panels are gapped .025-.040. If I try to heat both edges while keeping the torch still ,will they spread out and meet? Will I have to dab filler in while this is happening so the pool does not get too thin?

Thanks for your expertise!
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My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask.

[Northof49]

Personally, I wouldn't gap them. It's tricky enough to get the puddle to initially bridge the two. Once you get the puddle to bridge the two sides, you keep adding filler and advancing. Do you have a foot pedal or otherwise heat control? Makes it easier.
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1958 Karmann Ghia owner

[theKbStockpiler]

I just thought everyone gapped the panels like with a mig but there where no guides on the internet about it.


I'm thinking the beauty of the gap is that it is near impossible to get a patch panal cutout perfect so it serves the purpose of actually non-fitup and non-buckle. I have been doing the gap thing with a mig and have noticed that with only weld on one side of the panel , it tends to bow the panel towards the weld side when it cools.

What if you first bridge the gap by depositing weld on either side first,and then start your weld on the bridge with the tig method?
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My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask.

[eyetzr]

The general rule for leaving a gap is the thickness of the metal or a bit less. Weld in small steps to avoid warping & relieve the stress in the weld right after you weld. This is done by lightly tapping around the weld with your body hammer or a flat body spoon or file. Check out the type 3 forum, look for Clatter fast back build. Good luck
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I think he meant "rare", as in "not well-done"

[esde]

tig is nice for pieces that fit perfectly, you use a minimum amount of filler and heat, and get out before the excess heat warps everything to hell (if you're good and lucky). Trying to bridge the gap with a Tig is just going to be frustrating and disappointing, trust me I know. You'll either make big holes, or warp the panels to hell, unless you're really good. I've gotten the best results w mig, gapping the panels tightly, and using a mig machine with a pulse mode. You can also duplicate a pulse w how you set the machine and technique.
Less warping = less heat
Less heat = parts that fit perfectly.
I have great results easing an air operated flange punch to make a flange on one side, and rosette weld instead of trying to butt weld a seam in an otherwise flat area. The double thickness of the layered parts absorbs more heat without warping if you go slow so the panels will be more likely to stay where you clamp them.

[eyetzr]

Good plan with the flange on the patch. Tig is, as esde said tricky at best for a novice welder. Mig is a little more forgiving and easier.
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I think he meant "rare", as in "not well-done"

[theKbStockpiler]

I wanted to become a real welder guy so I have a tig setup on it's way. I'm working on sheet metal right now but I originally wanted to learn to tig for aluminum plate. With mig after the machine is adjusted there is not much variation with what the operator can do because most migs don't have a foot pedal. It's just a mater of the duration of the arc.

I don't have to leave a continous bead with a tig ,I could do virtually a series of spot welds as with a mig with a gap. The tig I ordered has pulse.

Knowing a gap is not usually used with tig helps a lot!
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My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask.

[eyetzr]

When I learned to weld it was with a torch, butt welding & metal finishing patches. No brazing, later I learned stick, upside down, welding up old frames & such. Mig came easy, pull trigger & weld. Tig I picked up after many people said it was tough, kinda like patting your head & rubbing your tummy, then switch directions. I love tig, tight fitting parts, almost no heat distortion (when done right lots, of practice) concentrated heat, good penetration. Shoot some pictures as you go.
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I think he meant "rare", as in "not well-done"