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  1. #1
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    Would you weld a truck frame with a 110v mig?

    Is it safe to weld a truck frame with a 110v welder? This has been beaten to death online. I say its not safe to do, others say its safe. Whats everybodys opinion on this?
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  2. #2
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    Exclamation

    Quote Originally Posted by scapegoat View Post
    Is it safe to weld a truck frame with a 110v welder? This has been beaten to death online. I say its not safe to do, others say its safe. Whats everybodys opinion on this?
    NO !!
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  3. #3
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    You know what they say about opinions....

    I would not do it, but I plan to live a long time, too.

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  4. #4
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    No way I'd attempt it.

  5. #5
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    Skill level is key here. I would have no problem doing it...however, it would go better with a heavier welder. A lot depends on where the joint is, and the stress involved. All that said, I would recommend you have at least 10 years of production MIG welding under your belt before you try it.
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  6. #6
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    I would say it depends on the fusion you can get out of the 110 mig and the type of wire used. I rented a little 110 job for my first experience with mig. After all the troubles a newbie with mig were solved I could lay a nice bead . Tried to attach some 1/4 pieces together in a tee joint and could knock them apart with a hammer. Oh well. Now many years later, I use 7018 to repair truck frame cracks. I don't recommend welding on frames, like adding a hydraulic kit to the frame. Bolt it on like everything else on the frame.

  7. #7
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    Quote Originally Posted by Rocky D View Post
    Skill level is key here. ...
    As is the design of the truck frame.

  8. #8
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    Quote Originally Posted by scapegoat View Post
    Is it safe to weld a truck frame with a 110v welder? This has been beaten to death online. I say its not safe to do, others say its safe. Whats everybodys opinion on this?
    Safe for....whom? The welder or the driver of the truck?

    Certainly the welder won't be harmed. Unless the frame breaks, the driver survives, and comes back and beats the stuffing out of the welder.

    Seriously, what it is it about truck frames that precludes Mig welding? The frames are surely less than 5/16" thick, and you're using 70ksi welding wire. Are the frames made of material that has much higher tensile strength than 70ksi? Or is it the heat affected zone that causes a problem?

    I'm just asking because I don't know.

  9. #9
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    Quote Originally Posted by cpurvis View Post
    ... The frames are surely less than 5/16" thick, and you're using 70ksi welding wire. Are the frames made of material that has much higher tensile strength than 70ksi? Or is it the heat affected zone that causes a problem?

    I'm just asking because I don't know.
    That's why I said it also depends on the truck frame. Some are even thinner than that. Some are thicker. Some are heat-treated steel, most are mild.

    Either way, thinking that a 120V MIG is an option for 5/16" structural welding is a bad first move...

  10. #10
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    Quote Originally Posted by cpurvis View Post
    Safe for....whom? The welder or the driver of the truck?

    Seriously, what it is it about truck frames that precludes Mig welding? The frames are surely less than 5/16" thick, and you're using 70ksi welding wire. Are the frames made of material that has much higher tensile strength than 70ksi? Or is it the heat affected zone that causes a problem?

    I'm just asking because I don't know.
    The guys here are giving you good advice, based on years of experience. Let me give you a different slant, based on welding theory, and my much more limited experience with a 110V MIG and a 230v Thunderbolt, which may help.

    The problem is neither the heat affected zone, nor the tensile strength of the wire. The problem is the amount of power a 110V MIG can put out. For any good weld, there must be sufficient heat to melt both the wire and both sides of the joint to sufficient depth to achieve good penetration. Melting the wire is relatively trivial, melting both sides of a thick joint is not.

    In order to melt both sides of a joint sufficiently for a good weld you are fighting a basic physical law. The power runs from the tip of the welder into the steel. This heats up the steel, but the heat has to go somewhere. Some of it is radiated into the air, and some is conducted to the air as well. Both of these are relatively small heat losses, compared to what the steel's effect will be.

    If you think about a flat butt joint, the heat created in the metal at the joint is going to be conducted by the metal to the rest of the weldment. This transfer is governed by the physical laws of heat transfer. Heat transfer is a complicated enough subject that it comprises two quarters of course work in an undergraduate mechanical engineering degree. Suffice it to say, however, that the larger the pieces of metal you are trying to join, the larger the heat sink that is soaking up the heat from the joint. If you make the pieces large enough, there simply won't be enough power coming from the welder to keep up with the conduction of heat by the pieces away from the joint. In other words, both sides of the joint will not melt sufficiently to fuse the metals together.

    One thing that can be done is to prepare the joint. In a thick butt joint, for example, we taper both sides down to a root gap where the metal is thin enough that the heat just can't get away fast enough to keep the metal from melting. At some thickness we can't really prepare the joint enough to accomplish good fusion with a 110v welder. Whether you can do enough joint preparation on the truck frame depends a lot on the geometry of the frame members. For example, if the frame is 1/8" C-channel, you can probably weld it with a 110v MIG, but you will be pushing the upper boundaries. An experienced welder could do it, I probably would not trust my welds there for a vehicle moving down the highway.

    The maximum input power to a 110v welder on a 20A circuit is 2200 watts, and a fair amount of that is lost in the welders windings. The maximum amount of power available to a 220v welder on 30A is 6600 watts, or three times as much. The 220v welder also loses a lot in the windings of the welder, but you still start with three times as much. A 220v stick welding pulling 50A starts with 11,000 watts of power, or about 5 times as much as the little 110v MIG.

    I know from experience with my little Hobart 140 that good welds can be done on 1/8" steel and a bit larger with proper preparation. If I get bigger than that, I have to make multiple passes and its a lot more hassle, not to mention the welds are probably more suspect. That is why I also have a 220v Thunderbolt that will melt a lot more steel and not have to worry about it.

    So to end this overly long epistle, welding is about heating metal enough to melt it. Big metal objects dissipate heat better than small metal objects. More voltage and more current on the input side of the welder puts more heat into the joint. Experienced welders know this instinctively, from using big and small welders.
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  11. #11
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    I think the bottom line would be...if you have to ask the question, then don't do it. Find someone that can. BTW it's not that MIG welding is precluded, but as MAC pointed out, they are all different, and will require different techniques. Are you planning to lengthen or shorten the frame? or just stick things on it?
    Arcin' and sparkin', Rocky D <><
    Experience is something you don't get until just after you need it.
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  12. #12
    Join Date
    Dec 2006
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    there are also DOT requirements and liablities that come into play with things on the road. no way

  13. #13
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    Quote Originally Posted by Rocky D View Post
    I think the bottom line would be...if you have to ask the question, then don't do it. Find someone that can. BTW it's not that MIG welding is precluded, but as MAC pointed out, they are all different, and will require different techniques. Are you planning to lengthen or shorten the frame? or just stick things on it?
    I don't think he is the one wanting to do the welding as he stated that he thought is was not safe.
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  14. #14
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    Sep 2004
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    I pre-heated my frame with O/A torch and got good fusion with 110 mig.

  15. #15
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    Dec 2006
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    Quote Originally Posted by BobJ View Post
    I pre-heated my frame with O/A torch and got good fusion with 110 mig.
    how did you verify your fusion?

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