Introduction: Small 110 Volt Arc Welder (NYDG)

Picture of Small 110 Volt Arc Welder (NYDG)

Im going to write a ton of Instructables on how to make Not your Dads Garage but work area designed for the future of builders. I will work in an evolution process to more and more complicated project, using project in past Instructables to help current project, assuming you have access to your dads tools (Hammer, Screwdriver, Saw, Drill,)
We will start by making a 110 Volt Arc Welder, 220 would be nice but most Instructable starters dont have a 220 outlet. It needs a little solder so you will need a soldering iron.

Step 1: Building the 110 Volt Arc Welder Housing

Picture of Building the 110 Volt Arc Welder Housing

Make sure its strong, it will way more that 100lbs
1. 2 x (30 inch x 24 inch x 1 inch) SIDE
2. 1 x (25 inch x 36 inch x 1 inch ) FLOOR
3. 2 x (24 inch x 36 inch x 1/2 inch) Levels
4. 4 x (36 inch x 4 inch x 1/2 inch) Walls
5. 1 x (37+ inch x 2 inch Dowel) HANDLE

Step 2: Electronical Parts

Picture of Electronical Parts

I have had the best luck getting microwaves from Secondhand stores, for free or less than 5$ each. But you could check the junk yard, and other places, just dont break yours for the parts (popcorn is better than a welder).

Electronic Parts
1. 10 x Microwaves @ 900+ Watts
2. C1: 600pf 2kv ceramic
3. C2: 0.1mf 400v epoxy
4. R1: 1M Linear potentiometer
5 .R2: 5k Linear potentiometer
6. C3: 22mf 250v electrolytic
7. Q1: IRKT71 SCR module
8. Q2: Lamp dimmer triac
9. BR1: RB152 1A bridge rectifier
10. D1: Trigger diac

1. Wire Cutters
2. Wire Strippers
3. Soldering iron
4. Drill
5. Basic screwdriver set
6. Elbow Grease

Step 3: Moding the Transformer

Picture of Moding the Transformer

Microwave oven transformers are step up transformers. That means that the voltage at the secondary winding is higher than the primary 120 volts. The secondary voltage is typically 4000 volts. Replace low voltage winding with #6 Single conductor wire, about 10-18 wraps. The load will change to 10 volt, and during welding will be about 2-4 volts at 250 amps.

Step 4: Electronical Parts

Picture of Electronical Parts

Assembling the Electronic Part onto the Caring Case.

Just follow the Schematics and make sure you get all the (step transformers) in the correct placement.

Easy to follow Schematic... Thanks too...., with minor changes.

Step 5: Finished Product

Picture of Finished Product

Special thanks to my electronics college teacher for giving me the idea and the special thanks to the web for donated material, pictures and information. Remember safety.


justjordy33 (author)2012-08-02

I think that is way cool a little box like that for chicago welding . With it only being 110 volt how much can it really do.

dciocoiu (author)2008-11-03

the microwve transformer emits Gama rais not electricity. dosent it ?

kj4sqr (author)dciocoiu2011-12-18

no the rads come from the emitter and it is not gama it is microwave waves
simple chart i use

toogers (author)dciocoiu2009-10-24

gamma rays? that would mutate the food. now i'm off to "shoot gamma rays at food."

toogers (author)toogers2009-10-24

lasermaster3531 (author)dciocoiu2009-01-21

Firstly, what are "Gama Rais"? Secondly, the microwave transformer does not give off anything but electricity and a little bit of heat. Thirdly, if you mean microwaves, the magnetron is what makes them and drools them into the cooking chamber.

dpsilver (author)lasermaster35312009-03-14

the magnetron makes microwaves not gamma rays

He means Gamma Rays and no it doesn't. It provides power to the magnetron which creates MICRO waves which heat water thus cooking food.

Saint_Awesome (author)dciocoiu2008-11-26

The transformer puts out plain old electricity, it's the 'magnetron' that puts out the microwaves that cook the food.

germeten (author)2011-12-18

I don't mean to be critical, but the project can be built a lot simpler. If you take a MOT (microwave oven transformer) and test the turns ration you'll find it's about 1:18. Turn it around and it's 18:1. So if you start with 120V you'll be stepping it down to 6V (measure it with a volt-meter, carefully!) Yes it will be AC but arc welders typically have a DC and AC mode. You can add a bridge rectifier for DC if you want to. Two reversed MOTS with parallel primaries and series secondaries will give you 12V output. Yes you can add more MOT's for more current output. Using a dimmer switch will reduce your power output because dimmers only use the trailing half of the wave, and dimmers don't really like inductive loads. They create "noisey" spikes that tend to heat -stress transformers, but only on half as long.

jlang2 (author)2011-08-04

I like popcorn but I disagree that popcorn is better than a welder. Popcorn is nice; welders make nice stuff. Nicer than popcorn.

teche (author)2011-06-11

so to make a welder i only need an instructible on how to build a soldering iron :)

CowGuy (author)2010-11-22

The secondary coil will be the one with the thinner wire correct?

CowGuy (author)CowGuy2010-11-22

These are my transformers, the top ones are the secondary and bottom ones primary or is it the other way around?

Emiliogiz (author)CowGuy2010-12-02

Yup, thats right. The top coils are the secondaries, which you need to slice off. The bottom coils are the primaries, which you should not touch or damage in any way.
Good luck!

jaymanx (author)2010-07-15

did that just say 10 microwaves? lol

shortyjk95 (author)2010-05-01

This is a little confusing on how to make it because 220 do the same thing on how to make it and I don't get what you are doing different can you help?

ewitwins (author)2010-02-11

Wait, so what sort of material did you use for your Welder Housing? It looks an awful lot like you used wood...

guds777 (author)2010-02-07

 the outlet for the owen in your kitchen is much hier amps, maby 40 amps.

dynamodan (author)2009-09-03

Thanks for crediting my site. The correct url to the article on my site is here: I originally came up with these plans and photos about 10 years ago and I also sell a downloadable pdf with even more photos and instructions.

juanoporras (author)dynamodan2009-12-04

thanks dynamodan, I saw your site before this instructable and I recommend it!, its much clearer I believe.

thanks to Kdemon too for sharing that info here!

josephprivott (author)2009-12-04

Nice writeup, Could you elaborate on the triacs more? I'd rather have a specific part than hunt around and get something that is an ill fit. What is your work in progress? I see it's on a swage block...

Prometheus (author)2006-05-22

Erm...Sure most "instructables" don't have a 220V outlet, but even fewer have a 120V 100 Amp source either...

In my city, the houses that run christmas lights to the max they can handle hire the electrical company to install an extra 100 amp service. The houses here are usually 50 or 100 depending on the age of the house. No one has a single outlet in their home that is capable of 100 amps. The most is 15 or 30 (maybe)

Derin (author)computerwiz_2222008-06-29


it is nice having 76kW at your disposal

did you know the transformers explode in case too many amps get pulled?(only the old types without a reset lever)and the new electronic one asks for a password or pulling of a lever for reset of internal breaker

toogers (author)Derin2009-10-24

hah, it's fun reading the subscript in a whisper, and the caps and bold in a yell.

Prometheus (author)Derin2008-07-01

Chill with the bold large type, that's just as bad as all-caps, maybe more rude. Please stick with the site's basic format. Good for you that you know HTML, noone cares. Also, transformers don't ask for passcodes, control panels do, and no mains transformer is properly-installed without a breaker. Transformers blow-up on the pole because the circuit is compromised earlier in the circuit than the intended protection, such as an insulation failure right where the feed comes into a building. Others explode due to improper maintenance, rebuild, or configuration mistakes, or from people typing in large and obnoxious bold print on a forum for no apparent reason.

Derin (author)Prometheus2008-07-01

ok ok correct it was the control panel for the transformer well yes but the electric company said it explodes because it is also a fuse,the newer ones have a lever to pull to reset and finally,I have seen a breaker box beside the transformer with the wire running into it

Prometheus (author)Derin2008-07-01

I apologize, I came down hard on you, it';s just the moderator in me. I've admined/moderated many forums, so I snapped on the etiquette you used. You seem to still be a good guy, so I'm letting it go as a honest mistake. Anyway.... The breaker-box may have been a cut-out (knife-switch) as a manual disconnect (for service repairs/inspection). Mains transformers are required to have a breaker or other over-current device between them and the load, some of which are not easily-recognizable to a layman as the familiar devices due to a differing construction. I agree to what you have seen, but interpretation relies on a shared observation.....meaning that if I saw it as you have, I could name what you have seen. In extremes, the "high-side breaker" (supply-side) will blow explosively, because it is open to the outside air and installed to protect the source, but keep in mind that this same reaction is enclosed on a 100-amp+ breaker when it trips as well, also trying to protect it's source. On average, there are over 40 breakers from the power-plant to your appliance in place to protect the higher circuits from an overload. Without them, one short in a domestic home would black-out a city-block or burn it down. Only two breakers separate an appliance from your mains, the remaining 38-average are on the poles leading to the power-plant, and within the plants themselves. Overcurrent devices in a circuit work on a hierarchy, which is why you have a dozen breakers for your home, and then you have one "mains" that will kill power to the whole structure if it trips or is toggled. Every domestic and commercial building, regardless of size, has this mains, which almost never blows under normal circumstances. This doubles as a "cut-out" when servicing or reconfiguring the structure's main wiring. All power-distribution circuits work on a "tree" structure. The trunk (mains) is your power-source, and there are "branch" circuits. To detail this structure in a post is impossible, but just in your home, your trunk line comes through your "mains breaker", and then feeds the branch circuits for your individual areas of the house, and further branches are done even per room for multiple outlets. Some branches split several times, some do not split at all, such as your heavy-appliance circuits like your range/dryer/clothes-washer outlet/dishwasher/water-heater/food-disposal/other hard-wired appliances. In light of this project however, an illegal tap to the mains (after the mains breaker please...for your own safety!) while managing your power-consumption of the residence as a whole could make this work. Your trunk load can be determined by yo7ur mains breaker, generally 150Amps for your average 1500 sq. foot house, but this estimate is very vague, check your actual mains breaker and your home's wanng health before proceeding.

Derin (author)Prometheus2008-07-01

ohh no prob noo not a blade switch (i think) ok and it is something like the picture correct ok then no it will not be illegal since it is mine Thank You for telling these facts and here is the picture:

Derin (author)Derin2008-07-01

and plus,I will not do this project

Derin (author)Derin2008-07-01

that image was a bug

common domestic outlet = 15 amps 120V
common dryer outlet = 30 amps 240V
common range outlet = 50 amps 240V

Still, a tough call to get that kind of power and still meet electrical code.

Hehe, I Australia where 240v is our main source we have: 10 amps 240v for the lights 15 amps 240v for the powerpoints 30 amps 240v for oven


Derin (author)Prometheus2008-03-22

maybe 380v (my three phase equivalent)could handle more amps

Derin (author)Derin2008-06-12

since it can feed a huge destroying machine and we have our own grid transformer so TAP INTO THE TRANSFORMER(for us turks that would be TRAFOYA GIR)

this is where capacitors come in : )

nickajeglin (author)Prometheus2009-06-05

All that you need to input into the transformers is the standard ~15 amps from your wall socket. The purpose of the re-wrapping the secondary windings is to lower the voltage and raise the amperage.

DeusXMachina (author)2007-07-18

Umm, I might be missing the boat, but what's the point in rewiring a step up transformer to step down? Why not just run it backwards? You'd end up getting about 3.6v at the electrode. Although, I guess the thickness of the secondary-now-primary windings would be somewhat troubling. It seems like it'd be a lot easier to take four or five transformers, link up all the secondaries (from the microwave point of view) in series and then put all the outputs in parallel.

dynamodan (author)DeusXMachina2009-09-03

Yeah you are missing the boat. The original secondary windings won't make a good primary, and the original primary isn't near heavy enough either. Trust me, I've tried it.

BTW these plans are ripped off from my site I originally came up with these plans and photos about 10 years ago and I also sell a downloadable pdf with even more photos and instructions.

bylerfamily (author)DeusXMachina2009-07-30

Well,that would lower the voltage,but amps is what is needed for welding so it would not weld much more than a pop can.

Prometheus (author)DeusXMachina2008-03-18

A reasonable idea, but hooking the secondaries in series and then the primaries in parallel will continually drop voltage through each transformer. Also, the transformer secondary with the greatest impedance will suffer the brunt of the current. If you are going that route, have several matching transformers and hook them all in parallel. However, 3.6V is not enough for even spot-welding (which you'll need at least 6.3V @ 600A+ for). For AC, you'll need at least 80 amps to be even remotely effective.

M4industries (author)2009-06-02


Syncubus (author)M4industries2009-06-10

Electronical: adj. of or relating to the sound one emits when becoming part of an electronic circuit.

M4industries (author)Syncubus2009-06-10


Metalcaster14 (author)2009-06-07

Hmm interesting... I'm 14 and my dad has been in my workshop twice. I bought all my tools with money from yard work. My favorite tool is my drill press! I bought it at a discount tool outlet for $60!

CoolKoon (author)2009-05-22

Just a quick note: high-contrast pictures (such as schematics, maps, simple drawings etc.) should never ever EVER be saved as JPG. It really messes them up a LOT (and doesn't compress them that good either). You should try PNG or GIF for those instead.

JZ Price (author)2009-03-18

I have been tiring to find a aprox. $ value for the 600pf 2kv ceramic 0.1mf 400v epoxy 22mf 250v electrolytic IRKT71 SCR module Lamp dimmer triac RB152 1A bridge rectifier Trigger diac I have tried mouser but i cant seem to find these things. How much tolerance do i have with these values, or is there a place i can slavage these,(eg. microwave, crt, old powersupply) thanks for your help

killrsheep (author)2009-02-27

Awesome instructable, that is a monster of a DIY welder nice job, i would add some wheels to the base tho

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