Welding Aluminum With A MIG Welder

Steve Martin had a bit that was like a fake infomercial where he says, “You can be a millionaire and never pay taxes!” The instructions were, “First, get a million dollars. Then,…” [Brandon’s] instructions for how to convert your MIG welder to do aluminum for under $25 is not quite like that, but you do need the right kind of MIG welder to make it work. In particular, you need an actual MIG welder that has a provision to connect external gas. The instructions show a Hobart Handler 140 that meets the criteria and has sufficient power to handle aluminum.

The main task is to replace the liner for the torch. The stock liner is steel which is fine for its intended purpose, but it is too rough for aluminum wire. A PTFE liner is inexpensive and will work fine with the aluminum wire. If you want to do normal welding later, you’ll need to put the original liner back in.

The other thing you’ll need is argon gas and the welder needs to be configured for solid wire and gas. The chart in the welder shows that you can use it for aluminum, but it does mention that it is difficult to feed with the stock liner.

Aluminum wire expands as it heats, so you need a slightly larger tip than the wire size. For example, in the video, [Brandon] uses .030″ wire and a .035″ tip. The relatively low amperage and duty cycle of the welder mean you need a small wire size.

Did it work? It did. He did preheat the work to help the small welder get the workpiece to temperature. It took a little experimenting to get the right angles and technique. In the end, he points out some of the benefits of having a machine meant to weld aluminum. However, for occasional use, this seems like a practical modification.

Sometimes welding takes a big bang. We don’t know how to create our own argon, but we did see someone make their own carbon dioxide shield gas, not long ago.

36 thoughts on “Welding Aluminum With A MIG Welder

  1. i’ve seen this tried before and it has to many fails in any actual useage. Al wire is just to soft and eventually/sooner rather than later ends up just gumming up somewhere along the line. just do it right and get a spool gun if you want to mig aluminum

    1. All it will do is Bird Nets up on the Rolls.You can get an 1/2 to 1″ of weld.Have the welder up hi wire down hill a little better still Nets Up.Just get a Pull Gun off Ebay for 120.00 and Weld All you want Forget It with a Mig-gun

    2. You need to use the right grade of welding wire. Cant remember what it is, but it’s much harder than regular ally. Never had any problems other than the current draw is massive so a large capacity machine is required.

          1. Steel welds are almost always stronger, aluminium ones…not so. Sure you can fuse together almost anything with aluminium as the parent metal, but the weld will be really weak if you use an incompatible alloy filler.

          2. I don’t actually know why it would be a problem, but I get the impression that you are fighting not only any oxide layer on the surface of the metal and welding wire, but aluminum’s tendency to form covalent bonds with other metals in the alloy if the heat treatment is wrong, leaving a brittle weld. I don’t know, just a guess about why you might get away with mixing and matching alloy and weld wire some of the time but not always. Something similar can lead to corrosion based failures with stainless steel, and is why you want to use a higher grade for the weld. The beneficial alloying elements can get tied up, rather than being in the solid solution to prevent corrosion.

          3. 316 and 304 are different alloys, not grades. They are used for different things depending on many factors. For instance, I believe 304 has more molybdenum than 316, which would make it less able to deal with certain caustic environments, like the hard water found in rural areas with limestone bedrock.

            Mixing alloys is not always a bad thing, but if you don’t understand the chemical properties of both, you will likely end up with properties you didn’t expect.

          4. That’s the sort of thing I was talking about, where do I find the tables that describe the various qualities of different types of steel, aluminum, and alloys? Things like tensile strength, sheer point, hardness, chemical reactions, chemical composition, temperature ranges, polymer memory. All my searches thus far result in tables that describe these qualities more as equations rather than plain English descriptions. Where do I find or pay for the information to allow me to experiment with confidence without another degree?

          5. Alloy numbering is not sequential, ‘higher grades’ are not somehow ‘better’ than ‘lower’ ones. It makes about as much sense as declaring that since RS-485 is a higher number than RS-232 so you can just mix the two together.

    3. And last but not least I see no mention of going from DC to AC. Hobart was bought by Miller and the Millermatic 180 has a kit with a switch to make the conversion. Yes, all aluminum MIG welders use a spool gun as Gambler pointed out.

    1. I have used Steel Mix with my wire feeder (Argon 75%, CO2 24%, O2 1%) for welding Steel Alloys, 100% Argon for doing Stainless and Aluminium ( Heliarc / TIG ) For heavy steel ( over 3/8″ ) I use a flux core wire welder.

    1. You can buy an NBC tap mig welder board from AliExpress I have several, you feed it with 24 volt ac , any small control transformer like in a gas furnace will work , it has a potentiometer and 2 dry contacts for when you pull the trigger it will activate gas silinoid or the pins 2 and 11 if you are useing a Miller trailblazer I have made several spool guns for about 40 bucks top of the line you can actually run wire and have potentiometer on spool gun handle to control wire feed .

  2. About 30 years ago, I bought a Clarke welder from Country General. It came with a video tape that showed how to use the little 110v mig welder to weld aluminum. It advocated the use of some kind of acid to cut the oxidation off of the aluminum (which rapidly forms) and aluminum welding wire. It showed the guy welding it up. I’m been under the understanding all this time that mig welding aluminum is possible. I have the video copied to my computer for preservation.

  3. Hello, folks. Lots of interesting discussion here, I feel you folks are willing to share secrets so the following generations can pick up where you left off. So my first question for the group; where does a self taught welder/fabricator find peer reviewed info on the various types and qualities of metals, and the respective specifications for appropriate usage. Gotten by ok up to this point, but now my skills exceed the capabilities of my Amazon special Flux core mig welder. My company is now to the point that I need to upgrade to a professional rig(I’m aiming for a multi-process rig), and due to accidental inventions I need to be more scientific in my R&D processes. Trouble is short of going to school(too busy with my company), finding accurate information is exceptionally time consuming. Help a brother out please and thank you.

  4. I make aluminum boats and trailers with both MIG and TIG. I have hobby-level MIG machines that are good up to 200A, and while could occasionally get a bead good enough to take a photo and post on social media, it was not up to the task when I really needed it. For instance, butt and lap joints sometimes work, but it would never put enough heat in for inside corner joints. If you want to MIG aluminum reliably, plan on spending $3-8k for a dedicated machine.

    1. The rig I’ve had an eye on can do steel and aluminum with some mods, mig (flux core/solid wire with shield gas)/tig/stick by Miller. The trouble is learning all the different quality of metals and what they are best used for. Things I can figure out with lots of testing, but I’d prefer not to waste material on things it can’t handle. I’m the build it to last then rebuild it to last type of maker. I didn’t come from money, and my company is just beginning to hit its stride, so wasting resources is a no-no.

  5. I had a “multiprocess” unit before they existed. A Hobart tr-250 ac/dc stick welder that was older than me. I either hooked it up to a Miller xr-30 push/pull wire feed for aluminum running ac. Or an airco feeder for mig process. Everything was ran with twecos so I could throw the standard rod holder on for stick also. It worked great until I got tired of moving 500lbs of equipment around every time I had to work.

  6. Most welding suppliers sell tips for aluminium wire which are slightly oversize. You also ideally want U grooved drive rollers, also keep the torch lead as straight as possible, do not kink the teflon liner, Remember to change to pure Argon and not mixed gas

    1. Yes – I’ve done this too. Keeping the run from machine to torch straight really helps with the inevidable kinking and reloading the wire.
      Second tip is, when you finish a weld, don’t release the trigger immediately, but pull the torch away from the work to break the arc, then release. This means you are still feeding wire when it goes cold, and it doesn’t gum up the tip with molten aly.
      Third tip is if the work is small, do the welding in an open-top box, because the Argon should pool around the job and not get wasted so much.

  7. WOW. I can’t believe people that don’t know chime in on some silly stuff.
    Flux core is used when high winds will push the gas away and create bad welds. The Flux core creates a gas at the point of the weld, same idea as stick welding.
    All aluminum has to be prepared before welding same as steel. Not cleaning oxidization (rust) from metals results in bad welds. (Aluminum creates a very hard surface layer when oxidized and needs to be prepped with a spray and some bow grease with a S/S brush.)
    Steel uses DC voltage
    Aluminum use AC.
    All mig welders having AC will have a spool gun. As someone pointed out not using one results in birds nest of wire inside.
    Aluminum can be welded as strong as any steel weld.
    Aluminum TIG rods come in different grades 5052, 6061 to match ( get this) color of the base material. 5052 base and 5052 rod will have the closest match in color of weld, etc. You can weld non matching material and still have a good strong weld as when using the same material.
    All this talk of a machine matching to a material type? If it welds steel, it can weld steel up to the thickness suggested, whether it’s mild. Cold rolled, hot rolled, etc. It’s steel.

    Lastly, if you watch the clowns on TV on the truck shows, car shows and makers; don’t follow their lead – you need to wear a helmet, longs sleeves, gloves even to tack weld. You are creating a plasma field, just like a sun. You can get cancer from not wearing the right equipment. Dirty welds where the joints are not sanded or brushed are weak sloopy welds, steel, S/S or aluminum no difference they need to be cleaned.

    1. I agree with you, dirty material leads to weak welds no matter kind of metal ferrous or non ferrous. I have welded aluminum with a stick and tig as well as steel, stainless and cast iron only with a stick though on cast iron.
      If it’s any help to whoever brush the hell out of the aluminum and wipe it with a rag and acetone before welding. Steel is awesome cause it’s forgiving and easy to weld. 7018 is the best rod for it. Flux core wire is good but more like welding with 6013 or farmers rod some call it. Learn how to run dual shield .045 it’s bad ass in any position and hard wire for thin stuff with a co² shield.

  8. lol .just change the nozzle,wire (aluminium Wire) and also gas type..using iron mig gas will not working on aluminium.again material just different.how can mix alum and iron wire….if you can,i need to learn something from your an experiance..

  9. This is a really great content, I can see how detailed you have gone through and explained about welding aluminum with a MIG welder. I love this article, thanks for producing such great contents. I love your posts always.

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