Additionally, the stick welder you get is definitely better than anycheap commercial welder you can buy.
Why is this homemade thing better than something you can buy? Because when you factor in shipping and labor and the little bit of retail markup - the companies that make typical cheap buzz boxes will skimp on copper as much as possible. Whereas you can use enough copper in this to make something really juicy, and still spend less, to nothing, compared to a store-bought arc welder.
So here's what you need to build a welder:
- Two beat up old microwaves
- Some 10 gauge wire
- Wire nuts
People throw out microwaves all the time, if you keep your eyes on the curbs.
Or, you can get microwaves at the local thrift store for $10 each.
Try the warehouse that processes donations - they have to pay to get rid of tons of broken ones.
Stuff you need for welding:
- Welding helmet ($16 and up)
- Welding rods ($6)
- Vice grip or purpose-built electrode holder ($6 for either)
- C clamp for grounding clamp
- Gloves
- Thick nonflammable (leather) clothing that will cover your arms
Disclaimer: High Voltage ELECTRICITY and lots of CURRENT! Heat, electrocution, and DANGER! You could die and you could go blind.
That said, try this at home!
See this for a lot of welding safety tips
Here are the really good how-tos that this project is informed by:
build a 70 amp welder
the tiny tim welder by tim williams
home made welding machine (via afrigadget)
Dan Hartman's how-to is good for reference, too.
And here's the quickest way to make a DC welder with a bunch of 12 volt batteries.
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Signing UpStep 1: Dissect the Microwaves
They'll love it. David Grosof donated one of these microwaves under the condition that we take it apart together.
Good safety tip:
You'll find a gigantic capacitor inside the microwave. It looks like a metal can with two tabs on top.
Short it out to make sure it doesn't have any leftover charge on it, before you poke your hands anywhere near. Just put a screwdriver or something metal you aren't connected to, across the two metal terminals shown here.

















































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Thanks; VERY useful ´ible.
First, I offer my condolences as well. I mean no offense what-so-ever in my following comments, as this is neither funny nor pleasing. With that said, I find it somewhat rude that you imply that this instructables author may be partially to blame for your sons horrific accident. Nobody forced him to pursue his endeavor into the field of high voltage experimentation. Despite the authors attempt at sarcasm (That said, try this at home!), there is warning about serious injury and possibly death.
There are many different projects that parts inside a microwave can be used for, all of which are quite dangerous. To assume that this article in specific is responsible for this tragedy, is not fair to the author or the instructables community. A more fitting comment would have been something to the effect of "We lost a loved one due to an accident caused by his curiosity of electronics and a high voltage project. Please, for the sake of your safety, be careful."
Again, I am sympathetic and sorry for your loss.
Nice build also, love all the idea's.
I'm not an electrician but it seems like it would be possible to tie the neutral leads from the transformers to the 220v neutral, connect the hot lead from one transformer to one of the 220v hot wires and the other transformer hot lead to the other 220v hot wire.
Now I have my transformers prepped and I'm not trying to spend money here, and I've used up my 10ga wire on new lighting and outlets in my garage. So I have 3 sets of 8ga jumper cables (stranded) or 12/14ga (solid) idr but about a good 50' left. Reccomendations on what I should do and how many wraps? Thank you.
Also one or two AC inputs, US 110VAC
1. How many power cords are actually plugged into the wall 1 or 2
2. Should the secondary cords be linked together between the two MOTs
3. Could someone please take detailed well lit pictures of how their welder is wired and post them
Thank you
Fidgety2
1) It's confusing [although they did a phenomenal job on this] because in the circuit drawing there are two wall receptacle cords supplying the x-formers, yet in the real life animated pic they have evidently supplied both x-formers with only one, which is probably wired in parallel. If both x-formers were inputted in series, instead of parallel, from one cord, it shouldn't work because of a division of the overall input voltage. Here in my region newer houses seem to have two separate cables in the wall, each supplying one of the two outlets in each individual receptacle. Therefore, i submit that there are good reasons to have two cords supplying your unit, and good reasons NOT to have just one, regardless of how hefty that one may be. 2 cords into any two outlets will take advantage of more power [and safe, third prong grounding] than any one under normal circumstances. With just one cord you are more likely to make your home wiring the limiting factor.
2) Yes, they should. Connect one of the wires you wound from one x-former, to one of the ones you wound from the other. You then need to follow their testing instructions. Remaining 2 of 4 wire leads that you wound go to the weld...doesn't matter which because this is AC not DC.
1) Will post pics ASAP. Meantime follow the "schematic" AKA wiring diagram/drawing that is obviously hand drawn...the one with pictures of two wall plugs and squiggly lines. I suggest you either put this project in wood, connect the third [green] wire from the wall to your chassis if using metal, or seek further advice on how to safely ground your project.
The ground is the round prong on the bottom of the plug. The ground carries overcurrent and is required for GFCI's to work. Ideally, the ground should be bonded to the frame and any other metallic surface that could become energized if the circuit shorts. This is for your protection -- current will follow the path of least resistance, the ground wire makes sure that current goes to ground through it instead of through you.
The hot prong, on modern plugs, is generally straight. If you're staring straight at the plug, the hot is on the left. The hot prong is the current carrying conductor coming straight from the breaker panel. It will shock the piss out of you.
The neutral prong, on modern plugs, is generally flared out a bit more than the hot prong. The neutral prong is the current carrying conductor that goes to the neutral bar of your circuit breaker panel. If you're staring straight at the plug, the neutral is the one on the right.
The NEUTRAL DOES CARRY CURRENT! Don't make the mistake of thinking it doesn't and get the shock of your life.
Here's mine
http://www.youtube.com/watch?v=XYc9lzQxKDA
I got 33VAC and it work well.
thank you
fidgety2