Making an ARC Welder – Part 1 of 2

I burned up the wires on my first Metal Melter,
I decided to turn the transformer core into a stick welder. But one transformer wasn’t
enough to actually make it weld anything. In this project we’ll be modifying 2 microwave
transformers, because more transformers means more power. For this project I scavenged parts from a
couple more microwaves. I found these for free on my local classifieds. Not only are
we using twice as many transformers here, but twice as much power. Seriously dangerous
amounts of power. These transformers are roughly the same size and look nearly identical except
for the placement of the bases. Using an angle grinder, we can cut down the seam of one of
the shallow welds holding this base plate to the transformer. The other seam is a little
trickier to get to, but once it’s cut you can see that the base plate can now be removed
fairly easily. Now these next few steps are gonna look a lot like the modification
we did in the Metal Melter project. After grinding the welds and opening the seam with
a chisel, the “I” section of the transformer can be pulled back to reveal the precious
primary and secondary coils. I’ve found that the primary coil can be removed by gently
prying up with a chisel. It’s important to work it out of the transformer gently because
the goal is to keep this in perfect condition. You might remember there are 2 magnetic shunts
that get knocked out next, and the low voltage winding gets removed because that won’t serve
any purpose here. Now to extract the secondary coil, my method of choice is to rest it loosely
on the jaws of a bench vice, then use a rubber hammer to knock down on the transformer until
the coil is free. This one finished up without any damage at all. If you don’t have a bench
vice, you can improvise with a couple of blocks of wood. In either case, your secondary coils
can be salvaged in near perfect condition. After a quick cleanup of the paper and resin,
our primary coil can be replaced on the transformer with the terminals facing down. We’re gonna be re-winding a new secondary, so it’s important that we have the flat side facing
up. When it comes to winding coils, life will be a lot simpler if we build a little jig.
I cut this piece of scrap wood so that it’s as wide as the center piece, and just a little
shorter than the top. The length is cut so that it overhangs the edges by about 1/2 inch
on either side. We can complete the form by adding a top and bottom panel, then forming a piece of paper to fit the sides. At this point, I think we’re about ready to add some cable. I found
this 50′ length of wire on clearance at the hardware store. This is 8 gauge stranded copper
wire, and cost me about $17. I’m gonna use my vice to hold the form in place, and
begin winding the cable around the center of the form as tightly as possible. We need
to build this coil 6 turns high, which isn’t too difficult the first layer, but gets progressively
more challenging on the second layer, and might seem like it’s near impossible on the
third. When it’s packed together 6 turns high and 3 layers deep, the paper flaps can be
folded over and taped together. Now this is the tricky part. We need to unscrew the top
and bottom panels to access our coil and separate it out of the from the form while keeping it in one piece.
I used some electrical tape to ensure the coil wouldn’t unravel. Okay, it’s time to transplant
our new secondary into the transformer. I have the best success by using a clamp to
pinch the sides in while I push the coil down into place. Let’s just double check the coil
sits flush at the top, and mix up some 2 part epoxy glue to finish up. Just like the transformer
in our Metal Melter project, the entire top area gets a liberal coating of epoxy just
before sealing it back together. In order for this to form a strong bond, the connection will
need a lot of pressure holding it together while it sets. This is where a set of clamps
or a bench vice can be invaluable. While our first transformer is setting, we can prepare
the second one in the exact same way. Our second coil is 18 turns of 8 gauge wire exactly
like the first, and transplanted just like before. Don’t worry too much about which way
the coil goes in. It doesn’t really matter yet. Finally, we can glue, and clamp that
together and leave it to set for around 24 hours. The final result should look something
like this. The connection is strong, and the coils are extremely snug, so any vibrations
will be kept to a minimum. Well there you have it. The basic makings of an AC stick
welding system, and these two electrodes will eventually become our clamp and stinger. From
this point, it really doesn’t take much more to finish the system up and turn it into a
useful little hobby welder. Look for how to do that in Part 2. Well that’s it for now.
If you liked this project, perhaps you’ll like some of my others. Check them out at

100 thoughts on “Making an ARC Welder – Part 1 of 2

  1. I have a 220v cord from a dryer. Can I just use that along with one repurposed transformer from a 1000 watt metal halide ballast? intead of wiring two transformers in series and using two outlets, I'd prefer just to use my one 220v outlet. Any help would be appreciated, thanks

  2. I got yet another batch of some questions that I really need answering:
    1. Can this homemade welder of yours melt aluminum cans and copper wires completely?
    2. Can arc welders that people usually buy in hardware stores melt aluminum cans and copper wires completely?
    3. Can both the dc and ac converter welders melt any kind of metal and if they do which ones?

  3. I've gone through 6 microwaves trying to find one with a transformer that is big enough to hold 18 wraps of 8ga wire. None of them could. What am I missing here? How can I find ones big enough?

  4. i used a small transformer and make 2ndary coil with 3 turns.
    but it didn't work at all. rather, it vibrates.
    can you help me in that?

  5. Amigo saludos desde honduras CA atte jorge.
    en este proyecto cuantas vueltas ó espiras de cable #8 se aplican a cada transfordor .

  6. Nice thing about AC is you need not worry much about arc blow, a condition caused by a buildup of magnetism caused by DC current.

  7. copper wire shud bee striped down and rapt in cooton sheets- insulation paper ,and varnish email lac after izolation.its best stands to heat .wire in pvc or plastic coat dont rezist heat especialy a welding transformer where have to stand in total shorcuts the secondary coils closed circuit,soryy for my english.

  8. How do you calculate the number of turn in secondary and how did you know that the current is sufficient for generating the required temperature?

  9. 220V IGBT ZX7 200 AMP Welding Machine MMA ARC DC Inverter. Was thinking of just paying the $60 for this. Then making the crucible the same way as video. As far as i can tell, the stats are the same. Would save me a bunch of time, and shock hazard. Any one following, see an issue in my theory?

  10. Why not use smaler cable so we can make more coil turns to get 30 v or over as secondary…so we need only one transformer?

  11. In which world does the parts come out that smoothly? For me, it took several hours just to take apart the transformer.

  12. how do you know the epoxy is liberal? did you interigate the epoxy for it's views on government? or did you just say it was liberal? pfft freakin liberals always trying to label stuff.

  13. What happen if the number of copper wire round is less or many ..and copper is too thin or too thick? Please reply…your answer will be very helpful for me thank you

  14. U said it doent matter which way the coil goes?
    Will the wrong winding direction of a coil result in little to no power?

  15. Incidentally there is no glue holding the coils together in your process of taking everything apart. You make it look so easy I'm frustrated.

  16. although after destroying one Transformer. I found out I can do this easily by knocking out the shunts first without destroying the coil LOL.

  17. Can anyone help me?
    So my problem is that one of my transformers is not as tall as his one is, so I just can't manage to fit 6 turns tall… Will it still work properly even if they have 5 turns tall instead of 6?

  18. I live in Austria but i could not find the 8 gauge wire
    Is there another standard for Germany? Or Europa?

  19. Can you use hps ballast kits to make the welder? The kit comes with what looks like a mot transformer…are they the same?

  20. Know I’m late to the party but has anyone done the math on this project? I.e resistance, amps, volts on both coils?

  21. When you're winding the secondary coil, are all three layers wound from the bottom to top? Or is the second layer would from top to bottom? Does that matter?

  22. Please keep all of his tips to help inspire us. If you want to take it down I understand, these comment dont help. But please keep the videos on an sd and share them. We will need them at some point or the kids will. For a better society.

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