A Field Expedient Welder Only MacGyver Could Love

If you needed to weld something in a pinch, what’s the minimum complement of equipment you could get away with? In [Professor Bardal]’s case, it’s a couple of motorcycle batteries and a roll of flux-core wire, and not much else.

We suspect this one is going to elicit quite a few comments, not least by the welding fans who no doubt will be triggered by just about everything in the video below, especially by characterizing this as MIG welding; it’s FCAW, or flux-core arc welding. But it bears some superficial similarities to MIG, at least insofar as there’s a consumable wire electrode through which a high-current DC supply flows, creating enough heat to melt it and the base metal. In this case, the current is provided by a pair of 12-volt motorcycle batteries hooked together in series. There’s also a torch of sorts — a short length of copper capillary tubing with a 1-mm inside diameter clamped in the jaws of a stick welder stinger, or a pair of locking pliers if you’re really in a pinch. The torch is connected to the negative terminal on the battery with a jumper cable, and the positive terminal is connected to the workpiece.

To create the weld, a piece of 0.8-mm flux-core welding wire is threaded through the capillary and into the joint, and fed by hand as it’s consumed. It’s awkward and awful, but it works. Of course, there’s no control over amperage as there would be with a legit welding machine, which would make it hard to adapt this method to different materials. Weld quality appears poor, too. But we suspect that if you were in a position to need a welder like this, you wouldn’t really care about any of that.

Fabricobbled welding rigs seem to be [Professor Bardal]’s thing — witness this much more professional MIG welder, complete with a baking soda and vinegar shielding gas generator.

Thanks to [Danjovic] for the tip.

46 thoughts on “A Field Expedient Welder Only MacGyver Could Love

  1. Perhaps the most amazing part is how he got a 9 minute video out of it…

    Anyway, nobody stated it was a good weld, so… yeah it “works”. This aint welding, it’s more like dripping candle wax on it so you no longer see the gap. Anyway, it’s the perfect hack to ruin your batteries and to create builds that can collapse at any moment.

      1. I wondered if he might’ve been saying “see” instead of “look.” The dialog on this one did leave someone to be desired, ha.

        That said, I love seeing hacked together stuff like this, personally. Gives me little bits and pieces of knowledge that can help when I’m cobbling together things!

        1. Yeah, there’s always something to be learned, even from this.

          Most people dont know that the impedance of batteries feeding a short circuit will cause them to work somewhat like a CC power supply, and if it has enough voltage to strike an arc, you can weld.

          I have friends that like to do drive offroad, and they fit the cars with double battery and carry a kg of 6013 SMAW electrodes, so if something breaks, they can wire the batteries in series and coble some repair to get back to somewhere they can call for help.

          With motorcycle batteries, you’ll fry them, but the usual lead-acid deep cycle batteries 60Ah batteries we find on automobiles, they can melt half a kg of steel and start your car for the months to come after the incident.

  2. I remember watching experienced welder MacGyver a weld using couple of truck batteries, welding rods and jumper cables to emergency weld in a snowstorm. The welded truck was roadworthy and made it to shelter.
    It’s not as dumb as it looks. The internal resistance in the batteries gives primitive current limiting. If you know what you are doing (and use the right rods) this can be permanent fix.

    1. Did this on the farm when I was a kid. Half a mile of freshly plowed field to the nearest road and a pair of of 250 amp 6 volt batteries right there on the tractor. Easy peasy. Be careful what you’re holding and try not to be standing in water because it’ll be a day or so before anyone notices you killed yourself.

    1. We’ve successfully used a ReadyWelder and 3 car batteries to re-attach some pretty chunky brackets to an axle in a field, they work great (and years later the axle is still attached as far as I’m aware) – basic MIG is only a ton of amps at a low DC voltage after all. All you need is flux-core wire to remove the need for shielding gas.

      I can definitely see carrying a dirt cheap stick electrode holder and a small bundle of rods as a great emergency welding setup – just make sure you have at least one running vehicle and don’t flatten everyone’s battery all at once.

      Worth saying you’ll also want a mask or about 5 pairs of sunglasses to actually see what you’re doing, but even auto masks are cheap these days.

  3. Time honored tradition of “keep some thin stick welding rods in your offroader and bank 2 batteries for 24v to booger that busted steering link into just about one piece just to get it out of the woods” welding. Whine about porosity, difficulty, and (largely overblown) hydrogen explosion risks, but 2 batteries, 2 sets of jumper cables, and a coat hanger beats nothing when the alternative is calling a wrecker.

  4. Nothing wrong with using a pair of 12V batteries in series to stick weld, it’s been done for decades, you’re not going to get a cert on the weld and it’s almost definitely not going to be pretty, it’s not going to do your batteries much good and you definitely don’t want those batteries in an enclosed space (lead acid batteries go off with quite a bang and splatter acid all over the place) but it can give you a perfectly functional field fix which gets you home.

  5. Welding is dangerous. No one should do it without having obtained a proper training and a welding certificate.
    Or as Bugs Bunny would have said it: Don’t do this at home, kids!

      1. Welding is an art in its own reign.
        A lot can be done wrong and then the injuries are not pleasant.
        Using a soldering station without prior training or and aid by your father/grandpa/friendly ham next door who teaches the basics can cause painful burns.

        Welding is one step further, because a layman without knowledge about safety rules can loose eye sight or destroy the nerve in his finger etc.
        He/she might not even know that bright light and the damps can be harmful without a “physical contact”.

        Just like how people of the past didn’t think that cheap sun glasses without UV protection do cause serious harm to the eyes.
        They didn’t consider that they cause the eyes to become wide open and then let the violent, invisible rays of light pass through.
        Once explained they fully understood, of course.

        Such “hacks” should thus always have a little warning, at least.
        It’s not about authority, but a matter of curtesy to the reader/viewer and caring about his/her wellbeing.
        Some out there don’t even have a realistic perception how much current a car or lead battery really has.

        There are many people who are enthusiastic about what they read/saw that they don’t think about the risks.
        After all, failures are seldomly being shared. It’s the success stories that are popular.

        1. While your are examples are true, it is also perfectly easy for people to weld safely and avoid all the pitfalls you raise without being a certified welder. Having basic welding and safety skills, even for TIG, isn’t that hard. There are also lots of sources of basic training available (local technical college, maker spaces, etc.) that can teach you to weld safely (and usually don’t give you a cert). Also, most of the certified welders I know encourage people interested in learning to weld (without gate keeping on qualifications).

          Now, if you are doing something like building a pressure vessel for deep diving submersible, then you really should consider hiring a welder with the appropriate certification (PVHO cert in this case).

          I think one of the biggest welding risks if people using (old) brake cleaner to clean parts before welding…

          1. Thank you for your understanding! I essentially meant to say the same.
            The certificate I mentioned simply is the end result of a successfully finished training curse.
            My father, for example, did obtain a certificate at our country’s equivalent to a technical college.
            The whole technical class had obtained a welding certificate at the end of year, if I remember the story correctly.
            Again, it wasn’t about business or authority but about practical lessons successfully learnt.

          1. Just think about how many people loose their fingers or hands on New Year’s Eve each year because they underestimate the strenght of “harmless” fireworks, espcially firecrackers.

    1. No need for certs. Most work doesn’t call for specific certs. Those that do are often done by a welder working under another’s cert. That or the company pays for a welder to get certified for the particular joint.

    2. I’m not entirely sure if your comment is meant as a joke or not. The welders (got arc, mig and tig) are probably the safest tools in my workshop.

      I’ve made an entire motorcycle frame from scratch, in my home workshop with an angle grinder and a welder and it’s EU certified road legal. It has about 80k kilometers on it. My training is watching YouTube video’s on how to weld. Welding is not difficult. In fact, it’s very easy. Preparing the weld, now that’s difficult.

  6. Almost every article presented here nowadays receive a lot o ‘not a hack’ comments.
    Then comes an article presenting a plain, good, old fahion Hack with a capital H and yet it receives a lot of criticism: ‘he should’t did this’ ‘he shouldn’t did that’ ‘he should have a PhD to do that’.
    C’mon guys, HAD is not ‘Complain-a-day’. detox yourselves from social media bad habits. Enjoy the hacks, enjoy the articles, learn something new, that’s the spirit!

    1. Agreed. One wonders how society survived with rogue welders joining metal together without any certification or training Why, I bet that sort of thing is still happening today!

    2. “C’mon guys, HAD is not ‘Complain-a-day”

      “But I wanted to go to Toshi Station and pick up some power converters!”
      (It’s funny the Markov Chain picked that Skywalker counter-comment first!)

    3. This website desperately needs upvote/downvote on comments otherwise we just get whichever internet expert posts first being forever at the top of the heap and it just goes downhill from there.

      In a better world the daft comments would quickly be downvoted into invisibility and the great nuggets of wisdom that are sometimes posted would float upwards.

    1. Have you heard of flux-cored wire as used in cheap gasless MIG welders?

      Besides cheapness I believe flux-cored is also more robust for use outdoors where strong wind could blow shielding gas away.

  7. Here in Oz I’ve been carrying a few welding rods and an arc welding glass insert on my 4WD trips for decades.
    Along with spare axles, a fuel pump, tie wire, bolts, tape, epoxy and a large bunch of other things.
    The rod is held in a jump start cable and a field expedient welding helmet can be made from a Cornflakes or other box with the glass taped in.

  8. I have heard of an ac version of this that uses line voltage with a bucket of sea water to limit current. A friend of mine saw it when he was hunting in Baja and brought back samples. They looked really good considering how they were made.

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