torison spring repair

My 7' X 10' garage door spring just broke. It is a torsion type, approx 3/8" in diameter and about 7' long when on its axle.
I have 140A-120V Mig and a Lincoln 'tombstone' AD/DC welder. If this spring can be welded (I don't see why it can't be) how would one go about re-tempering it? I have a single burner propane forge that the spring (at least 12" at a time) will fit in. I would rather buy a new one than have to replace it twice. But if one can safely weld and retemper, I would love to try it. . . . . . . in advance, thanks. . charlie.
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Try sci . engr . joining . welding group
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I'd say that your chances of hardening and then tempering the welded up area to exactly the same point without screwing up any other part of the spring are about zero. Even if you are close, that area is going to act a little differently and, again, in my opinion, create a stress point the will eventually, if not sooner, fail again. Your chances of choosing a welding rod or wire that is a perfect match to the failed spring are poor. As you said, you can only heat about one foot of the spring at a time. That means that you'd have to harden and temper each foot. In addition, you probably don't know the exact analysis of the spring material, so how could you devise an accurate heat treatment plan anyway? I'd buy the new spring and make a LOT of "Strikers", repousse' tools and screwdrivers out of the rest of it.
Pete Stanaitis ------------------
Pintlar wrote:

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No clue what correct heat treating for such a spring would be. But when they break, the guys that fix these things normally just use a U-Bolt to connect the two broken ends together as a temporary fix and then order a replacement. I'm sure that would be easier for you than welding and attempting to heat treat. They claim however that it won't last long once it breaks because the whole spring is typically developing stress cracks by that point so within weeks it's likely to break again in another place.
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Curt Welch http://CurtWelch.Com /
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Curt, Thanks for that tip. It may be a lifesaver as it has just started snowing here and it will be up to my butt soon. SW Montana. 5300 asl. . . . I'm embarrased I never thought of that. I am going to get two 5/16 cable Crosbies and try that until I can locate a replacement for a real odd spring. I may even drag my 120v- 140 Amp mig to my garage to tack the broken spring ends, between the clamps.. . . . .charlie *************************************

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