Build a Microwave Transformer Homemade Stick/Arc Welder

Em Destaque
I had no idea making a DIY welder would be so easy to do. And, it's pretty much FREE!

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.

Passo 1: Dissect the Microwaves

Invite your non-hardware oriented pals over to help help dissect your donor appliances.
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.
Post a comment
Be nice!

Nós temos uma política de comentários em que todos devem ser gentis.
Por favor, seja positivo e construtivo.

squiddarling diz: Set 3, 2014. 6:18 AM

Hexavalent chromium (a.k.a chrome 6 mentioned below) is carcinogenic. Just a heads up, that you NEED a mask...

hhofkhan diz: Mai 21, 2014. 12:55 PM

between 16 to 24 volts but not more than 24

this+is+my+user+name diz: Mar 25, 2014. 8:35 AM

does anyone know what the standard output is on one of these transformers?

ihemkes diz: Mai 20, 2014. 10:55 AM

Its about 1.2kV

esumon diz: Jan 22, 2014. 7:40 PM

my microwaven primary side was burned . so i have difficult to make this . any body can tell me . how many turn need for primary( for input 220 (50\Hz)volt supply ) side and which gauge wire ?

TheLegendaryLegacy diz: Jan 6, 2014. 7:14 PM
Can I have three transformers on lower voltages?
subodh101 diz: Dez 15, 2013. 11:01 PM
Can somebody tell me the two transformers specifications if I want to buy those as new ones or if I can find a single one for this kind of diy.
TheLegendaryLegacy diz: Ago 7, 2013. 11 AM
Im also running like 14 gauge wire for the secondary.
TheLegendaryLegacy diz: Ago 7, 2013. 9:41 AM
So i got the transformers all wound up and ready, when i tested it, it came out to a 30.9v output and im ok with that, but i fogot to unplug it while it was on the multimeter. So over the course of 10-15 minutes the primary coil got hot. one transformer puts out 13v and the other 17v and the the 17v one got hotter but both primarys were pretty hot. should i be worried or is it because i had it on too long.
themudball diz: Ago 4, 2013. 3:20 PM
i only had 600 volt wire for the secondary, i wrapped two coils in each transformer, ya think that's why i'm not getting good amps?
sirward77 diz: Jun 29, 2013. 4:20 AM
I constantly emailed this site post page to all my friends, because if prefer to read it then my all friends will too.
metal fabrication
alahamm diz: Mai 16, 2013. 6:27 PM
Hi star; I just got the secondary out and I see that the primary is separated from the filament winding by a few metal plates. SHOULD or SHOULDN´T I remove these?
Thanks; VERY useful ´ible.
ktekishikuchichiku diz: Mar 11, 2013. 8:13 PM

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.
crazy-blender diz: Mar 26, 2013. 10:52 AM
i am sorry
somebody12345 diz: Mar 10, 2013. 11:17 AM
lol the link for welding rods actully goes to a drip irrigation kit maybe you should fix it
sphawes diz: Fev 9, 2013. 7:48 AM
Ive built mine using two transformers wired in series. I was only able to get about fifteen winds in my secondary coil for each of them. Being a new welder, i get the stick stuck to my piece quite often, causing my fuse to blow. Is there a way i could wire it up better so that this wont happen, or is it just a matter of not sucking so much at welding?
HeatUp diz: Fev 6, 2013. 10:46 AM
plz answer me how much i need turns and how much wire plz answer thanks:)
HeatUp diz: Fev 6, 2013. 10:48 AM
oh and i live in 220 zone
Rebelturtle diz: Jan 26, 2013. 6:22 PM
I love the 1980's electronic baseball game in the back of the one pic. I remember having one of those and burned many of hours playing that game.
Nice build also, love all the idea's.
HeatUp diz: Jan 12, 2013. 3:15 AM
how much i need wire if i live in 220 zone?plz answer
Tempted diz: Dez 28, 2012. 4:45 AM
The steps here are very vague and difficult to read. Are there any more user friendly plans laying around?
AllendaleGreen diz: Dez 27, 2012. 5:18 PM
I've a question about the power source(s) for this welder; could it be wired to work with a 220v AC (U.S.) service as opposed to plugging it in to two separate 110v AC circuits?

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.
mykiscool diz: Dez 14, 2012. 8:07 PM
Just want to let you know that the welding rod links to an irrigation kit.
billbillt diz: Nov 14, 2012. 12:36 PM
PheonixZip diz: Out 3, 2012. 5:17 PM

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
m5industriesinc diz: Set 22, 2012. 7:58 PM
whos the gurl?
DrDontDoDis diz: Ago 19, 2012. 12:57 PM
Thanks for the instructable! My first time welding and it works like a charm!
stasterisk diz: Ago 20, 2012. 11:30 AM
That's what I love to hear! Post pics?
lloydrmc diz: Ago 15, 2012. 12:40 AM
Great 'able. The Harbor Freight electrode holder you list has since been discontinued, and the SKU reused. This costs a little more, and it should do the trick:
stasterisk diz: Ago 20, 2012. 11:31 AM
updated the link — thanks!
taoybb-TH diz: Ago 1, 2012. 9:59 AM
Have to said thank you! I'm done it too! Thank you again!

Here's mine

I got 33VAC and it work well.
fidgety2 diz: Jun 21, 2012. 9:34 AM
ok i have everything hooked up and am ready to weld i have 7018 rods will these work please advise

thank you
n1cod3mus diz: Jun 19, 2012. 4:49 AM
after yesterdays ramblings I got bored of keep working out how many turns i would need to produce the amps and voltage so i wrote a calculator feel free to use it
n1cod3mus diz: Jun 19, 2012. 5:17 AM
I have updated this with a few wire gauges and their top amps they can take and got it to work out if it would fail e.g. end up melting and causing a fire
n1cod3mus diz: Jun 18, 2012. 4:39 PM
i'm in the UK so if i took one of my transformers with 112 turns on the primary, the UK mains voltage is 230v and about 13amps so...

230v * 20 turns on 2nd = 4600

4600 / 112 turns on primary = 42.67v

13amps * 230v = 2990w (could round it up to 3000w)

is that correct? if so then surely i would only need a single transformer to do the welding? as you guys are using 2 to achieve output voltage of a simlar value

which would mean i would be getting over 100amps right?
n1cod3mus diz: Jun 18, 2012. 5:28 PM
i was just reading about how to calculate the amps on this site

looking at number 4 it says that if your reducing 120v to 12v your doing it by a factor of 10 and thus the input amps would be times that factor to give you the ouput.

to work out my amps i would assume i would need to work out the factor for my voltage so

input 230v / out put 41.67 = 5.51

input 13amps * 5.51 = 71.63amps out

am i doing this right? I think this should be the approximate amount of amps i would be putting out from 1 transformer
n1cod3mus diz: Jun 18, 2012. 5:39 PM
i know i'm answering my own questions here but i'm hoping that this will help others. and hey its near 2am here in the UK so i'm doing my best work.... more caffine.
n1cod3mus diz: Jun 18, 2012. 6:02 PM
ok so looking around the net most home welders produce upwards of 80amps and around 34v and up.

what this means the the US is that with your 50amps (as above) you will need more so doubling up your transformers gives you 100amps and your in the golden zone.

with my higher power and slightly higher amps with one tansformer I would only be able to get 71.63amps so its clear i also need to double up too.

so heres what i got, I have 2 transformers with the following

A) 112 turns on the primary

B) 132 turns on the primary

assuming I will be doing 20 turns on the secondary and the input voltage is 230v with 13amps, i work out its output and my factor for each transformer and then work out its amps

working out A)
230v * 20 turns on 2nd = 4600

4600 / 112 turns on primary = 41.67v output

input 230v / output 41.67v = 5.51 (the factor)

input 13amps * 5.51 (the factor) = 71.63 amps output

working out B)
230v * 20 turns on 2nd = 4600

4600 / 132 turns on primary = 34.8v output

input 230v / output 34.8v = 6.60 (the factor)

input 13amps * 6.60 (the factor) = 85.8 amps output


so once i combine the 2 transformers output

85.8 amps + 71.63 amps = 157.43 amps total output

41.67 volts + 34.8 volts = 76.47 volts total output

now the problem is what wire do i use, i found this site which has a handy table for the amps different wires can handle

so i need wire that can handle up to 85.8 amps for B) and 71.63 amps for A)

looking at the chart i found I would need to use 7 gauge wire in the UK which can handle up to 89amps as you guys in the US are generating around 50amps 10 gauge is fine.

problem with this is that 7 gauge is much thicker so will i get the turns in, well thats where someone on instructables has the answer, you have to work out the area you have to use check this out

this is a series of videos that explain how to prep the transforms and in one of them it shows how to work out the area and how to wind your cable to use the best space and if the wire your planning to use will fit.
n1cod3mus diz: Jun 18, 2012. 6:16 PM
just been working this out if i wanted to use 10 gauge wire i would have to have an additional 10 turns so 30 turns and not 20, if anyone wanted to know, again you have to make sure this will fit, if not you will have to increase the turns and thus reducing the amps and you can use thinner wire
n1cod3mus diz: Jun 18, 2012. 6:20 PM
the only other way you could get round using 10 gauge with 20 turns is to introduce cooling, otherwise the wire will just melt and fuse together and then your stuffed.

good job i salvaged the fans from those microwaves, of course if you used wire that is enamel coated then i suspect you could fit the 7 guage in, but i'm thinking it will be tricky if its covered in a standard insulation.

i'm rambling i should go to bed, its 2.20am
fidgety2 diz: Jun 18, 2012. 8:04 AM
I have a couple of questions
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
dumpstar diz: Jun 28, 2012. 5:20 AM
I would love to see a reply to this comment-- these are the same questions I have!!!!
Easymkay diz: Ago 4, 2012. 11:09 PM
OK, I'll try:
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.
theloyz diz: Mai 29, 2012. 4:32 PM
I don't know if this just sounds dumb, but since i'm Kind if new at this kind of thing I'll ask anyway. if you wanted the most output amps, couldn't you just have like two turns of super thick wire on the secondary coil?
Easymkay diz: Ago 5, 2012. 12:30 AM
A few months ago my nephew asked me why dogs noses are cold, so there are no dumb questions. The reason that would not work is that the amps and volts are inversely proportional to each other given the input. The inputs overall work capacity force must necessarily equal the outputs, because that's the total energy available. I, too, thought that amps was the chief factor to a powerful weld, and it still is. However, without enough volts [pressure] into the output, the weld will not begin or maintain, for these purposes. For a spot welder, per se, you would be correct, as they evidently go higher on the amps, way lower on the volts, but will only minimally "weld" thin metal. Here is a project of your exact description: #4 gauge thick output wire, only a few turns, huge amps, only a couple volts:
KCMude diz: Mai 26, 2012. 5:13 PM
Hey Engineers, technicians, Craftsmen and many more in this forum, am happy to report that following instructions is easy. With 2.5mm diameter wire 18 turns on the secondary was able to get 18.5volts hence, I must be able to get 37volts if I manage to make the second transformer. I will give a full report when my project comes to an end.
from Kaychi.
Misac-kun diz: Mai 23, 2012. 8:07 AM
Do i really need two transformes or just a 220V one will do? If yes how much turn the second coil will need or just link me a calculator for this, if there is one or just the formula.
fidgety2 diz: Abr 27, 2012. 9:02 AM
Would jumper cables work for the 10 guage wire or would that be too small
YtekSpouki diz: Mar 26, 2012. 8:46 AM
Can I connect ground to my wall ground ?!? Or where ??? Is Ground the center tap of both transformers ?? and when they are in parallele ?
firebird2000 diz: Mar 22, 2012. 4:40 PM
Your link to "welding rods" is really an auto-matic plant water-er...
oskymike diz: Mar 15, 2012. 4:33 PM
wahay,found a microwave unit down the street,just striped the secondary out tnite so looking for some suitable wire to re-wind,was thinking of an old starter motor or something simular,P.S.,if you want to control the power out then put your dimmer or what-ever in the mains lead input,NOT OUTPUT!
OVERLOADED diz: Fev 21, 2012. 4:45 AM
wouldnt wiring the sec in parallel give you double the amps?
oskymike diz: Mar 15, 2012. 4:37 PM
yup,ya got that one right,push pull sort of thing,wire them up then check the voltage on the output,(careful,currant ,not voltage kills)
OVERLOADED diz: Mar 15, 2012. 6:35 PM
yes thats right thanks i got zapped by 60kv and didint die lol but its funny im a welder and i can zap myslef with sparks of about 3/4 inches from the tig machine on my finger and not feel any jolting ? can you explain why?
OVERLOADED diz: Fev 21, 2012. 4:42 AM
does wiring the sec in series also give you double the voltage ?
philmcclure diz: Jul 8, 2012. 8:34 AM
No. Wiring in series boosts current. Wiring in parallel boosts voltage.
OVERLOADED diz: Jul 8, 2012. 11:08 AM
thx wasint too sure about trans or even why i asked that question so long ago?
jps99 diz: Jul 11, 2012. 8:01 AM
Sorry, but wiring in series boosts voltage, not current.. Two 6 volt batteries in series gives you 12 volts. In parallel, gives you 6 volts at twice he current.
philmcclure diz: Jul 11, 2012. 7:24 PM
Sorry, you're right. In series current stays the same, in parallel voltage stays the same. Long night.
OVERLOADED diz: Jul 12, 2012. 12:16 AM
correct,no need to be sorry for nature lol. it is what it is.
stick2wire diz: Nov 21, 2011. 7:56 PM
I am converting a 220v 140amp buzz box to a wire welder....I would like to convert the 220 line voltage to DC with a bridge question is can I place the rectifier before the transformer on the line voltage, and if so, how do I wire the rectifiers...
Thank You..........
The+4th+Doctor diz: Dez 7, 2011. 9:28 PM
This will not work, transformers run on ac. also depending on the amount of impedance used to balance the transformer it could draw way too much current if you feed it dc.

so you need to rectify it after the transformer, look at the wikipedia page on bridge rectifiers for more information

that bridge should handle some welding if you can give it time to cool off (in theory anyway)

stacking them should work fine
pyrogreasemonkey diz: Nov 14, 2011. 7:29 PM
alturnative to using thick wire: just wind two wires ! yo can just take many small wires and solder them at the ends to make one big wire.
sandra.nunn diz: Out 26, 2011. 6:13 AM
On July 5, 2011 our son was accidentally electrocuted to death in our driveway. He was building, what we and the police believe to be this apparatus. The last website on his computer was this one and there was a microwave oven that was partially disassembled on his bed. He was not wearing gloves. He was 20 years old and is expecting a baby. The loss we have suffered is great. We feel that your site minimized the actual danger involved when working with such a powerful high voltage piece of equipment. Your warning disclaimer was followed by the statement: "That said, try this at home!". Further down your site states "Invite your non-hardware oriented pals to help dissect your donor appliances." Twenty year-olds tend to see themselves as invincible, and danger and death sometimes doesn't seem real to them. Your statement, "You could die...", really did happen- to our son.
Balerich diz: Mai 23, 2012. 6:24 AM
I read your comment about your sonshorrible accident and I am now deeply moved to express my deepest condolence. I am a father and my son means the world to me.. The loss of your son is a tragedy that hurts even to imagine. I will take this as a serendipitous lesson and will reaccess my aproach to safety. I will strive to be wise and to practice patience. Thank you for helping us. Farewell
tmelnik diz: Out 16, 2011. 2:31 PM
so..... i just wanna know this... does the ends of the secondarys (where the actual welding is being done), does the secondary connect anywhere!? like how do you get power to the secondary if the ends are just the welding stick, and the ground?
dph84 diz: Dez 12, 2011. 9:37 PM
Listen very carefully--if you don't understand how power gets to the secondary--then DO NOT attempt to build this device. (at least not at this time) Because that is extremely evident to anyone qualified to build this. I'm not trying to sound rude. I'm simply stating that it is basic electrical theory. The answer to your question is that in an AC circuit, a coil creates an electromagnetic field which expands and can induce a voltage on another coil. The primary coils being energized make an electromagnetic coupling which is the basis of how ALL transformers work. You may have some experience with DC cirucits and I want to encourage you to learn your way up to the point where this instructable is obvious to you, too. But as far as now, be SAFE, and don't mess around with this circuit. If you want proof, check out the extremely sad story that young man's mother wrote on a previous page.

majada diz: Set 28, 2011. 12:28 PM
here are the pics of the tower. sorry if im not allowed to sell things, just thought someone might be able to use it.
sealman diz: Out 14, 2011. 1:15 PM
what is your location. and how much
majada diz: Set 28, 2011. 12 PM
hey i have a couple 115v STEP DOWN transformers, will those work? do you think i need one or two?

i also have a gigantic transformer from a big cell tower thing. it was a power supply for some kind of print shop. its is about 9ft tall with all kinds of circuits and switches and what not. it might be too big for the welder i wanna build though.

Im looking to sell that whole tower thing if anyone is interested who is in the atlanta area, you can PM me for pictures or i might post on here. it had two transformers but i was broke and had to scrap it. got about 90 bucks for it.
huaxiangseo diz: Set 22, 2011. 8:39 PM
WASHINGTON/ISLAMABAD (Reuters) - The top U.S. military Christian Louboutin Knockoffs officer accused Pakistani intelligence on Thursday Louboutin Outlet of backing violence against U.S. targets including the American Embassy in Afghanistan, a stunning remark that fueled a war of words and seemed certain to deepen tensions in South Asia.Admiral Mike Mullen said Christian Louboutin Shoes Pakistan's Inter-Services Intelligence agency (ISI) played a role in Christian Louboutin Sale the September 13 attack on the U.S. Embassy in Kabul, supporting Louboutin Shoes militants known as the Haqqani network.That network, he said, is a "veritable arm" of the Christian Louboutin Outlet ISI.The embassy attack was the latest in a series Louboutin Sale of violent episodes that were a blow to U.S. efforts to bring the Afghan war to a Cheap Louboutin peaceful close.Pakistan's interior minister rejected the U.S. accusations of Islamabad's links Christian Louboutin Collection to the Haqqanis, one of the most feared insurgent groups operating in Afghanistan.The minister, Rehman Malik, also warned against a unilateral U.S. ground attack on the Haqqanis, who are based in Christian Louboutins Pakistan's ungoverned tribal territories."The Pakistan nation will not allow the boots on our ground, never.

Christian Louboutin Clearance
Cheap Christian Louboutin
Discount Christian Louboutin
Christian Louboutin Cheap
Christian Louboutin For Cheap
Christian Louboutin Discount
Christian Louboutin On Sale
Christian Louboutin
Christian Louboutin UK
Christian Louboutin 2011
Christian Louboutin Online
Christian Louboutin Shop
Christian Louboutin Store
Christian Louboutin Boots
Christian Louboutin Women

Our government is already cooperating with Christian the U.S. ... but they also must respect our sovereignty," Malik said in an interview with Christian Louboutin Replica Reuters.The harsh words Replica Christian Louboutin appear to represent a new Christian Louboutin Sneakers low in U.S.-Pakistani relations, which had barely begun to recover from the unannounced U.S. Special Forces raid that killed Osama bin Laden in the Pakistani city of Abbottabad in May.COMPLETE BREAK IN Christian Louboutin Knockoff TIES UNLIKELYThe tensions could have repercussions across Asia, from India, Pakistan's economically booming arch-rival, to China, which has edged closer to Pakistan in recent years.A complete break Louboutin between the United States and Pakistan --
T+Bomber diz: Ago 21, 2011. 10:54 AM
I don't know much about electricity,but I know there are different types of 10 gauge wire(solid,multistrand,different types of sheathing etc).My question is-which type would be best?I'm scrounging all the other parts,but considering the dough I'm saving by building my own,i have no problem shelling out some money on wire.Plus i'd just as soon not have to redo it if it melts.Thanks
cenzo188 diz: Ago 22, 2011. 1:54 PM
If you want some nice wire, order it here:
this is the stuff I used. It's 20 bucks for a hundred feet, and the insulation is nice and flexible, and easy to wind. As for melting, it hasn't melted on mine.
cenzo188 diz: Ago 14, 2011. 12:09 PM
I am building one of these now, and I was wondering about some sort of control circuitry. You used a variac, but my variac can only handle 4 amps.
Would a light dimmer, the way it adjusts the duty cycle, be effective at all? I would replace the tiny triac with a 50 amp one of course, using just the control circuits.
cenzo188 diz: Ago 16, 2011. 9:18 AM
I'm going to have to try it, because this thing has way too much current. It's melting my workpieces.
FC77 diz: Ago 12, 2011. 7:46 AM
How would you change the current from ac to dc . Would you put a bridge rectifier and if so , just say the welder were putting out 20volts at 70amp for instance , what current and voltage should the rectifier be ? Would you put one that can handle more than the given power and would it be one , two ,or three phase if any ? By the way you are all awesome , these write ups are so funny AND educational not to mention extremely helpful ! lol :-)
snotty diz: Ago 2, 2011. 9:51 PM
Yeah! I've made two of these. This one was made from small Japanese microwaves so I had to use three transformers.

Fun fact: multistrand wire windings will overheat and meltdown spectacularly. So use 10 gauge solid wire.

zanki_kitsune diz: Jul 27, 2011. 1:39 PM
have you thought about placing a light dimmer on on of the transformers power cables so you can somewhat control the power of the welder?
snotty diz: Dez 11, 2011. 12:04 PM
Yeah I've thought about it but I haven't done it yet.
The+4th+Doctor diz: Dez 12, 2011. 8:56 PM
uuuuh did you guys read the instructable (step 11)

light dimmers typically aren't rated for inductive loads not sure what the typical wattage is either but it will work as long as it doesn't pop, if you have one on hand id recommend trying it.

the speed controller mentioned in the comments should work without any problems if that fails. don't forget to use a 20% off coupon.
Callum+Snowden diz: Jul 24, 2011. 12:44 AM
I like the note by the fuse on the 3rd picture ;)
applegeek diz: Jun 28, 2011. 4:39 PM
I think it would be cool if stasterisk added a page on here about how to add taps and switches on the transformer to vary the voltage without buying a special, and probably expensive, dimmer.
applegeek diz: Jun 28, 2011. 4:27 AM
Are 1/8" rods too big for this welder? Also, what duty cycle would you recommend?
applegeek diz: Jun 14, 2011. 6:35 AM
Is there a certain wattage you would recommend for microwaves on this? If I picked up 2 microwaves that were only about 700 watts each, would I still be able to make a good welder?
seoer2010 diz: Mai 25, 2011. 12:18 AM
The MBT Sale bow of "Pirates of the Caribbean: On Stranger MBT Shoes Clearance Tides" had the lowest percentage of domestic 3D grosses of any non-family film MBT Anti Shoe since "Avatar" -- below MBT Walking Shoes even the heavily panned 3D conversion "Clash of the Titans." It was just 46%.Does MBT Shoes that mean it's time to question the durability MBT Shoes 2011 of 3D with U.S. auds? Not necessarily."Clash" rode a wave of interest in the MBT Sandals format following "Avatar" but battled negative word of mouth for its rushed conversion, tallying 52% of its MBT Sandals 2011 opening gross from 3D. "Stranger Tides" debuted Stateside with $90 million this weekend, but 37% of that was in 3D, with an additional 9% from Imax engagements, according MBT Kisumu Sandals to Disney stats released Monday."Clash" bowed in fewer 3D locations, with 1,602 (or 42% of the total location count), compared to "Stranger Tides," which opened at 2,747 3D engagements (66% of its total locations).While MBT Kisumu Women opening 3D shares have wildly fluctuated MBT Kisumu Sandals For Women since "Clash" -- ranging from 95% for "Piranha 3D" to 50% for "Gulliver's Travels" -- it seems audiences haven't been embracing the MBT Sandals Sale format to the extent they did when "Avatar" set the 3D gold standard.
seoer2010 diz: Mai 4, 2011. 11:18 PM
"I can understand the conundrum Air Max Shoes that commanders are in about how much can you tell," said defense Air Max Shop analyst Paul Giarra, a retired U.S. naval officer.Nike Air Max "Because it's news that's good for morale and it also makes it clear to al-Qaida that they're losing.Air Max That's important. They need to know they're losing."Revealing too much, on the other hand,Air Max UK can give the upper hand to groups like al-Qaida, Giarra said.Gauging how much to Air Max Store tell is a growing Air Max Outletchallenge as military special operation groups increasingly work side by side with Air Max the intelligence community, like the SEALs and CIA did Sunday. There are benefits to touting such fantastic successes,Nike Air Max something the U.S. government has long seized upon:Kobe Shoes President Franklin D. Roosevelt Nike Kobe ordered Marines Nike Zoom Kobe photographed raising the flag on Iwo Jima to come home and be identified so they could use interest in the picture Nike Kobe Shoes to raise billions of Kobe Basketball Shoes dollars in war bonds.
seoer2010 diz: Abr 29, 2011. 12:10 AM
Government Asics Running lawyers defending limits on the marketing of new drugs ran into Asics Shoes sharply skeptical questions Tuesday Onitsuka Tiger at the Supreme Court from conservative justices who said the 1st MBT Sale Amendment protected the free-speech rights of drug makers to market their products directly to doctors.At issue is whether states can forbid MBT Shoes pharmacies from selling to drug makers the confidential prescription records of MBT Shoes 2011 physicians. Armed with this information, drug company salesmen have targeted doctors who are not prescribing new and costly brand-name MBT Shoes Clearance drugs.Vermont's doctors were surprised to learn their confidential prescription records were being sold. "They were completely Air Force 1 unaware the drug marketers had access to their prescription records. They Nike Air Force 1 thought this compromised the physician-patient Air Jordan relationship, and that it was driving up the cost of pharmaceuticals," Paul Harrington, executive vice president of the Vermont Medical Society, said in an interview.Vermont's Cheap Jordan lawmakers agreed, noting that spending on Nike Air Jordan prescription drugs had nearly doubled in five years. To protect Air Jordan 2011 the privacy of doctors and to contain health costs, the state in 2007 prohibited pharmacies or insurers from selling prescription records for the "marketing or promoting" of drugs.
WERNER+SLABBERT diz: Abr 28, 2011. 7:36 AM
oh and also would it be possible to submerge this whole build into a mineral oil for cooling?
WERNER+SLABBERT diz: Abr 28, 2011. 7:35 AM
at The risk of sounding "Lekker" Daft in South africa our elec is at a minimum of 220 volts. how would this affect the build? and how would i need to adapt the plans to accommedate for this.
magiccowy diz: Jun 11, 2011. 5:17 AM
Shouldn't be a problem but he says it on step 5. Aus has 240v and its working okay for me but I'm still on one MoT.
microedit diz: Jul 14, 2011. 11:25 PM
number of secondary windings is affected....there is a formula or use meter to get correct voltage
seoer2010 diz: Abr 27, 2011. 1:36 AM
We are not targeting him specifically, but we do consider command and control targets to be legitimate targets wherever we find them," Gates told reporters in Washington after a meeting with his British counterpart, Air Max ShoesLiam Fox.Although Gates said such targets have been considered legitimate from the beginning of the Nike Air MaxNATO-led air campaign more than one month ago, the initial bombing focus was on Gadhafi's air defenses, supply depots and Nike Zoom Kobe maneuvering ground forces.Now NATO is attempting to Air Max ratchet up pressure on Gadhafi and Kobe Shoes those in his inner circle by holding at risk his command centers as well Nike Air Maxas related Nike Kobe structures Kobe Basketball Shoes that enable the regime to exercise power.The bombardment Tuesday was constant throughout the afternoon and into the evening, and loud explosions could be heard Air Max thundering across the city.The rebels received another boost Tuesday when the Obama administration said it has Air Max Shop eased its sanctions on Air Max Store Libya to allow for the sale of oil controlled by the opposition. The move will allow Air Max Outlet the rebel forces to use the income from oil sales to purchase weapons and other supplies.
winnerceramics diz: Abr 14, 2011. 7:26 PM
I made one using two microwave transformers with the primary windings wired in series to run it off of the 240 volt outlet. like the one you plug a dryer into. I burnt up the first one i made. It got too hot and the secondary windings shorted out and i fried it. So the second one I made I submerged in used motor oil. this extended the duty cycle. I could then weld longer. A good source for free microwaves is craigslist I got more microwaves than i needed for free there. Just remember to be careful when dissembling the microwaves as some of the older microwaves with the better transformers have a capacitor in them that may not have a device to drain it when not in use so the transformer may be live. those transformers have enough voltage to kill you so be safe.
spark+light diz: Jun 23, 2011. 12:30 AM
Duty cycle?
That's a measure of the onetime percentage of a square wave.
Do you mean life?
winnerceramics diz: Jun 24, 2011. 4:18 PM
The professional welders I talked too used the term duty cycle to describe the amount of time the welder can be in use in a ten minute period producing a welding current safely. It is usually expressed as a percentage. So a 40% duty cycle would mean that the welder must be rested for six minutes after four minutes of continuous use. By submerging the transformers in motor oil i increased the duty cycle of the welder as the oil better dispersed the heat generated from the transformers than air.
spark+light diz: Jun 24, 2011. 5:06 PM
Thanks for telling me!
I was getting kind of confused by some of the comments. :D
egammoc diz: Abr 9, 2011. 10:32 AM
would 1 transformer out of a UPS (uninterpretable power supply) it supports 2 screens and 2 modems. and surge protects 2 of anything.

all i know about its model is
Manufacturer: ULTRA
Model: RCD-UPS1500D
Item: UPS (Uninterpretable Power Supply) Battery Backup
egammoc diz: Abr 9, 2011. 10:34 AM
woul one of those work? i want this to make a sidehack bmx bike
outofyurworld diz: Abr 1, 2011. 4:08 PM
I have found 2 MOT's and have wired them together with 2mm or 1/16" Vinyl coated wire. I wrapped them very tightly. When they are plugged in, I get a reading of 28 ACV. When I attempt to "weld" the sparks aren't even close to bright, just orange. Does anybody have any advice on how to increase to voltage to 35-40 ACV?
seoer2010 diz: Mar 23, 2011. 8:01 PM
Tokyo - Japan's worries, the supply of food and water Adidas Jeremy Scott Shoes to rise sharply proof warning radiation leakage tsunami - from Japan damaged Jeremy Scott Shop nuclear power plant to Tokyo for the Adidas Jeremy Scott baby tap water safety level of long-term Angle. Residents clear store shelves after the bottled Adidas Jeremy Scott Wings water Shintaro ishihara, says Tokyo President level radioactive iodine more than Jeremy Scott double tap water was considered safe for baby food. In the city officials entreaty, buy only what they need, said hoarding could hurt the tens of thousands of people Jeremy Scott Adidas have no water in March 11 area has been devastated by the earthquake and tsunami. "I have never seen Jeremy Scott Adidas Wings such a thing
jtasch diz: Mar 21, 2011. 6:27 PM
Is the welding set up that's made from microwave transformers a MIG set up?
wheel-horse diz: Abr 2, 2011. 2:15 PM
No, It is an Arc set up (more comonly known as "stick welding")
fidibiri diz: Jun 6, 2011. 8:36 AM
SMAW (Shielded Metal Arc Welding) being precise, while MIG stands for Metal Inert Gas which is a type of GMAW (Gas Metal Arc Welding)
seoer2010 diz: Mar 16, 2011. 7:12 PM
However, former U.S. Ambassador Nike High Heels to NATO Robert Hunter--who dealt with Nike Heels many of the same debates about no-fly-zones and UN resolutions during the Bosnia and Kosovo conflicts in the 1990s--argues that Jordan Heels an international intervention in Libya need not be so complex: A no-fly zone can be imposed in a matter of hours, likely with low military risk, as NATO Nike Dunk Heels demonstrated over Bosnia in the mid-1990s and as a coalition did over Iraq after 1991. As Gates argued, this might also require Jordan High Heels suppressing Libyan air defenses -- but that is also Dunk Heels a relatively straightforward military proposition. In sum, the course is clear. Washington should push for the Air Jordan Heels rapid institution of a no-fly zone against the Qaddafi regime. This no-fly zone could be undertaken by NATO, the European Union, or by a "coalition of the willing" that includes the United States, France, the United Kingdom, and a few others.
No-Shi-De diz: Mar 12, 2011. 10:33 AM
hey! this is cool! not to doubt, but thus this really work and is safe to use? or is thier a danger that if done wrong, the voltage can arc through u or something can go boom. not sure if im asking the right question, i dont know much about high voltage stuffs. just curious...
Toastalicious diz: Abr 8, 2011. 9:27 PM
you can hurt yourself with a store bought machine. you can hurt yourself with this machine. you can even hurt yourself by plugging something in. You won't hurt yourself if your careful, so you know, be careful?
No-Shi-De diz: Abr 10, 2011. 9:12 AM
hahaha! i understand, but i mean, is thier like a green light to indicate... (hey, u've done a good job with me, u can use me now w/o worrying) or is there a red light that if this certain sound is created thier's something wrong. (so watch out for an arc) ????? =D i had already tried welding, but not much on how it works.... i've read some, but not technically aware of the parts that can be substituded like wats being done here.... so thats the part im not sure (scared) of....
everlastwelders diz: Fev 28, 2011. 9:40 AM
As a welder I will surely try this out.
ARJOON diz: Fev 28, 2011. 2:50 AM
i just made mine. with 2 1000w mots. but when i use it. my rod becomes red hot and do not fuse. can anyone tells me what is the problem
snowluck2345 diz: Abr 30, 2011. 3:44 PM
sounds like your not striking an arc. You need to have a clean end of your electrode and tap/strike it on the metal then lift it back and try to mantain a consistent arc lenght of about 1/4".
microedit diz: Jul 14, 2011. 11:23 PM
add another winding or two for higher voltage, amperage only comes into play when resistance is high on stuff being welded
NAILS1978 diz: Fev 19, 2011. 10:49 PM
By all means correct me if im wrong, i could take my little comercial stick welder apart and re wind with bigger and more wire ??
jkinrade diz: Fev 2, 2011. 2:51 PM
As this is an AC welder, does anybody know if this will work for aluminum? I don't like the electronics involved in a homemade TIG....
Emiliano+Valencia diz: Fev 3, 2011. 10:43 AM
I dont think it'll wrk 'cause that needs high frequency AC, not only 50 or 60 Hz.

Not sure.
doityoureself diz: Fev 10, 2011. 11:49 PM
I have the tig gun and hose-cables-argon-CO2 setup and I actually tried it and it does not work, tungsten electrode just sticks to the aluminum. I also do not know all the electronics involved in TIG welding but I am going to try to get this to work, if anyone has any ideas feel free to jump in and let me know. A higher frequency 120 or 240vac seems to be needed as emihackr97 stated because it did spark or hum at about 1-2 times a second (60hz , 120 times a minuite, sparks both top and bottom of the sine wave) but it would not hold the arc. I feel that if the voltage was higher(I have about 50vac max) and at higher frequency(maybe in the 300 to 400 range, it would work.
seoer2010 diz: Jan 25, 2011. 7:59 PM
The recalls spanned more than 10 million UGG 5854 vehicles around the world for faulty floor mats, sticky gas pedals, software glitches and other defects, but mostly in North America. Toyota UGG Classic Tall was the only major automaker to see its North American vehicle sales drop last year compared to UGG 5825 the previous year. Other automakers staged a recovery from the global financial crisis. Toyota's North American sales last year totaled 1.94 million vehicles, down 2 percent from 2009, with 1.76 million of that total in the U.S.

UGG Classic Short
Classic Short UGGS
Short UGG Boots
UGG Bailey Button
Bailey Button UGG Boots
UGG Button Boots

Toyota fared better in its home UGG 5803 Japanese market, where tax UGG Tall Boots breaks and government incentives for green vehicles kept its Prius gas-electric hybrid sales UGG Knighstbridge booming. The Prius ranked as Japan's top-selling car in 2010 with UGG Knighstbridge Boots nnual sales of 315,669 cars, hitting an all-time high for any nameplate and a 51 percent increase from the previous year. Toyota's sales in Japan jumped 10 UGG 5119 percent last year to 2.20 million vehicles, despite a sluggish economy.
stasterisk diz: Jan 9, 2011. 5:55 PM
Thank you to all the instructables users who are answering questions in the comments here.
doityoureself diz: Jan 9, 2011. 1:50 AM
I really like the clean look but one problem, no way to get any cooling, no vents or fan
doityoureself diz: Jan 9, 2011. 1:17 AM
I am getting ready to rewire my transformers, I have a ton of 6ga copper wire but it has no insulation on the wire, any ideas on what to use, other that electrical tape?
stasterisk diz: Jan 9, 2011. 5:55 PM
Are you sure it is uninsulated, or is it enamel coated? i.e., If you take a small piece of it and nick it with a blade, does the copper seem to be of a different color than it is on the surface? (this would suggest enamel insulation, in which case you are ready to go.)

Also, do NOT insulate bare copper with electrical tape to make it insulated: your inductors will be vibrating and getting knocked about (no matter how careful you are) and the tape will eventually slip and create a short somewhere.
evjim diz: Jan 24, 2011. 1:19 PM
Enamel coating is not enough for the welding environment. Enamel can easily be scratched off when working around metal and it will be hard to tell if the coating is still there since it is a similar color.

Be safe and buy some heat shrink tubing or buy new wire. It really won't cost much.
ac-dc diz: Fev 19, 2011. 7:58 PM
That is false, the wire already on the transformer is enamel coated, besides which you aren't going to be attacking the welder with pieces of metal - which could be pretty dangerous to do to ANYTHING plugged into an AC outlet.

Further, "new wire" for transformer windings IS enamel coated. There is a catch though, when you are winding wire on an existing welded-together E core transformer it is very easy to scrape the wire against the metal core which could scrape off the enamel (or other *painted on* insulation).

Also, don't step on cracks or cross a black cat's path. ;)
ferball diz: Jan 3, 2011. 10:07 AM
What rods are used? I have my welder working, but I can not lay a beed, does rod size make a difference, or is my voltage to low?
doityoureself diz: Fev 10, 2011. 7:18 PM
I found unless you have at least 35 to 40 volts its not enough. I had to put 3 transformers wired in series to get enough voltage. I used 8ga stranded wire with 12 to 15 turns on each transformer. at first I tried the 6011 electrodes at 1/8 inch diameter and it would not bead good at all. I switched to 6013 electrodes at 3/32 and wow, it lays great beads, I have welded 1/4inch steel no problem, great penetration, 1/8 inch with good results too, just have to move a little faster. Also I use three extension cords, plug each transformer to an extension cord and plug the extension cord to an outlet that is on a different curcuit breakers. you may be able to plug 2 transformers in on the same cord if it is on a 20 amp curcuit. any more will probably trip breakers when running long beads. also I use a small room fan on a low speed and aim it right at the transformers and they stay nice and cool even under heavy loads. Good luck and let me know if I can help or maybe let me know how your progress is going I would be interested.
seoer2010 diz: Dez 3, 2010. 6:43 PM
jordan heels for women
Rep. Joseph Crowley, a Democrat from air jordan high heels New York, stood beside a giant picture of the late Leona Helmsley cuddling her dog, Trouble, who inherited $12 million from Helmsley's estate when she died. "Under the Republican plan, if Trouble doesn't get a tax break, air jordan heels nobody else should," Crowley said. "Under the Republicans' plan, this country will go to the dogs. They'll protect this little dog, but they won't protect the middle class of this country." While the liberal jordan high heels Democrats framed their their case as the rich versus the poor, moderates like Rep. Chris Van Hollen (D-Md.) argued that the country can no longer afford to keep tax cuts jordan heels for the wealthy in place. "With our annual deficits now approaching $1 trillion and our debt approaching $14 trillion, it's the right thing to do to make sure our economy is on a sustainable future," Van Hollen said.

high heel jordans
jordan high heels for women
jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women
jordan heel boots
jordan heels & boots
jordan heels and boot
jordans high heels
women air jordan heel
jordan women heels
air jordan heels for sale
air jordan boots
womens jordan high heels
high heels jordans
cheap jordan heels
women jordan boots
christian louboutin boots
women heels boots
women's boots
jordan women boots

McConnell suggested that once air jordan high heels Congress has dealt with the expiring tax cuts and budget issues, "if there's time left for other matters," it's possible the jordan high heels for women Senate could get to START this year. And McConnell said nothing to revoke his declaration after the election that his top goal as Senate majority leader will be to deprive Obama of a second term in the White House, which could prove to be a pretty big impediment to compromise.

jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women
jordan heel boots
jordan heels & boots
jordan heels and boot
jordans high heels
women air jordan heel
jordan women heels
air jordan heels for sale
air jordan boots
womens jordan high heels
high heels jordans
cheap jordan heels
women jordan boots
christian louboutin heels
women heels boots
women's boots
jordan women boots
jordan heels
air jordan heels
jordan high heels
jordan heels for women
high heel jordans

Obama said the private women jordan heels meeting, without White House or congressional aides, was never going to be easy "in the current hyperpartisan climate" but was women air jordan heel nonetheless different from standoffs of the past. "A lot of times, coming out of these meetings, both sides jordan women heels claim they want to work together but try to paint the opponent as unyielding and unwilling to cooperate. Both sides come to the table, they read their talking points, then they head out to the microphones trying to win the news cycle, instead of solving problems. And it becomes just another move in an old Washington game," Obama said.

jordans heels
jordan boots for women
jordan heel boots
jordan heels & boots
jordan heels and boot
jordans high heels
air jordan heels for sale
air jordan boots
womens jordan high heels
high heels jordans
cheap jordan heels
women jordan boots
christian louboutin heels
women heels boots
women's boots
jordan women boots
jordan heels
air jordan heels
jordan high heels
air jordan high heels
jordan heels for women
high heel jordans
jordan high heels for women
jordan heels boots
air jordans heels
jordan high heel

Obama said the private meeting, without air jordan high heels White House or congressional aides, was never going to be easy "in the current hyperpartisan climate" but was jordans high heels nonetheless different from standoffs of the past. "A lot of times, coming out of these meetings, both sides claim women air jordan heel they want to work together but try to paint the opponent as unyielding and unwilling to cooperate. Both sides come to the table, they read their talking points, then they head out to the microphones trying to win the news cycle, instead of solving problems. And it becomes just another move in an old Washington game," Obama said.

jordan heels
air jordan heels
jordan high heels
jordan heels for women
high heel jordans
jordan high heels for women
jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women
jordan heel boots
jordan heels & boots
jordan heels and boot
jordan women heels
air jordan heels for sale
air jordan boots
womens jordan high heels
high heels jordans
cheap jordan heels
women jordan boots
christian louboutin heels
women heels boots
women's boots
jordan women boots

Obama said the private jordan heels meeting, without White House or congressional aides, was never going to be easy "in the current hyperpartisan climate" but was air jordan heels nonetheless different from standoffs of the past. "A lot of times, coming out of these meetings, both sides claim they want to work together but try to paint the opponent as unyielding and unwilling to cooperate. Both sides come to the jordan high heels table, they read their talking points, then they head out to the microphones trying to win the news cycle, instead of solving problems. And it becomes just another move in an old Washington game," Obama said.

air jordan high heels
jordan heels for women
high heel jordans
jordan high heels for women
jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women

Obama said the private meeting, without air jordan high heels White House or congressional aides, was never going to be easy "in the current hyperpartisan climate" but was jordan heels for women nonetheless different from standoffs of high heel jordans the past. "A lot of times, coming out of these meetings, both sides claim they want to work together but try to paint the opponent as unyielding and unwilling to cooperate. Both sides come to the table, they read their talking points, then they head out to the microphones trying to win the news cycle, instead of solving problems. And it becomes just another move in an old Washington game," Obama said.

jordan heels
air jordan heels
jordan high heels
jordan high heels for women
jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women

Obama said the private meeting, without jordan heels for women White House or congressional aides, was never going to be easy "in the current high heel jordans hyperpartisan climate" but was nonetheless different from standoffs of the past. "A lot of times, coming out of these meetings, both sides claim they want to work together but try to paint the opponent as unyielding and unwilling to cooperate. Both sides come to the table, they read their jordan high heels for women talking points, then they head out to the microphones trying to win the news cycle, instead of solving problems. And it becomes just another move in an old Washington game," Obama said.

jordan heels
air jordan heels
jordan high heels
air jordan high heels
jordan heels boots
air jordans heels
women jordan heels
jordan high heel
jordans heels
jordan boots for women
Bob_144 diz: Nov 15, 2010. 5:51 PM
would you be able to help with some tips for making this transformer work for a welder??? its from an old master-craft battery charger.
ferball diz: Nov 15, 2010. 7:20 AM
Would a standard light dimmer on the 120 v in wire work for power control?
applegeek diz: Jun 26, 2011. 1:56 PM
You would probably melt it very quickly. They are rated for only 400 watts and welders use much more than that.
Timofte+Andrei diz: Nov 12, 2010. 11:25 PM
that's a cool instructable :) my grandpa,here in romania, has a home made welder but it's 50 times bigger and heavy than this:D oh, and it's eating too many kWh :)) and because of heat i need to repair the wall sockets every 2months :D
Computothought diz: Nov 11, 2010. 1:22 PM
Gotta try this.
Opcom diz: Nov 11, 2010. 9:26 AM

This is a great project and also re-uses transformers that would otherwise be pitched. The saved copper from the secondary is valuable too. If high tech controls like a dimmer or tapped choke is not available, a bucket of strong salt water solution can be used on the primary. Have a 2x4 above it with two (or more in parallel) heavy steel electrodes coming down thorugh it, and as the assembly is lowered so that the electrodes are more immersed in the solution, it will pass more current. It can limit the current yet keep the open circuit voltage high. bubbling vats of electrolyte are not for the faint of heart but neither is this instructable.  We're fortunate here to have enough 'junk' to make great things from. Here's another very low-buck home made welder, similar in some ways but it's seen an awful lot of use, which is the interesting part.
breinhardt diz: Nov 9, 2010. 5:11 PM
stick welding on stainless releases chrome 6. if you're going to stick weld stainless, wear a respirator.
thelmer44 diz: Nov 9, 2010. 11:02 AM
This seems somewhat dangerous... But cool nonetheless.
PaulMakesThings diz: Nov 9, 2010. 1:52 PM
Yeah, but there are lot's of sites for safe kids projects. I like that instructables allows stuff that assumes some level of caution and maturity, or at least acceptance of liability.
seoer2010 diz: Out 29, 2010. 6:27 PM
This week, the makers of Back To The Future kicked off celebrations marking the 25th anniversary of the release of the original movie starring Michael J. Fox. In the same week, an Irish independent filmmaker has gone public with what he says is footage of a time traveller caught walking through a scene on a recent DVD release of Charlie Chaplin's 1928 film, The Circus. "I believe I'm the first person to find something quite unusual from a bit of film footage from 1928," Clarke said. The scene can be found in the extras menu in Documents, under The Hollywood Premiere.
Discount UGG Boots
UGG Boots On Sale
UGG Classic Boots
Buy UGG Boots
UGG Womens Boots
UGG Boots Clearance
UGGS For Cheap
UGG Outlet
UGG For Sale
UGG Boots Outlet
Cheap UGG Boots
UGG Boots For Cheap
UGG Outlet Store
UGG Boots UK
UGG Boots De
UGG Boots Noway
The problem with a deal that establishes use of low-enriched Iranian uranium is that it "would provide Iran the international legitimization that it has long sought for its uranium enrichment program," ISIS said. "With such legitimization, Iran would face few objections to perfecting and enlarging" its so-called breakout capability to quickly fabricate an actual atomic weapon with the complicated centrifuges it uses for enrichment.
Discount UGG Boots
UGG Boots On Sale
UGG Classic Boots
Buy UGG Boots
UGG Womens Boots
UGG Outlet
UGG For Sale
UGG Boots Outlet
Cheap UGG Boots
UGG Boots For Cheap
UGG Outlet Store
UGG Boots UK
UGG Boots NL
UGG Boots FR
UGG Boots De
UGG Boots Noway
seoer2010 diz: Out 29, 2010. 6:25 PM
This week, the makers of Back To The Future kicked off celebrations marking the 25th anniversary of the release of the original movie starring Michael J. Fox. In the same week, an Irish independent filmmaker has gone public with what he says is footage of a time traveller caught walking through a scene on a recent DVD release of Charlie Chaplin's 1928 film, The Circus. "I believe I'm the first person to find something quite unusual from a bit of film footage from 1928," Clarke said. The scene can be found in the extras menu in Documents, under The Hollywood Premiere.
Discount UGG Boots
UGG Boots On Sale
UGG Classic Boots
Buy UGG Boots
UGG Womens Boots
UGG Boots Clearance
UGGS For Cheap
UGG Outlet
UGG For Sale
UGG Boots Outlet
Cheap UGG Boots
UGG Boots For Cheap
UGG Outlet Store
UGG Boots UK
UGG Boots De
UGG Boots Noway
The problem with a deal that establishes use of low-enriched Iranian uranium is that it "would provide Iran the international legitimization that it has long sought for its uranium enrichment program," ISIS said. "With such legitimization, Iran would face few objections to perfecting and enlarging" its so-called breakout capability to quickly fabricate an actual atomic weapon with the complicated centrifuges it uses for enrichment.
Discount UGG Boots
UGG Boots On Sale
UGG Classic Boots
Buy UGG Boots
UGG Womens Boots
UGG Outlet
UGG For Sale
UGG Boots Outlet
Cheap UGG Boots
UGG Boots For Cheap
UGG Outlet Store
UGG Boots UK
UGG Boots NL
UGG Boots FR
UGG Boots De
UGG Boots Noway
Styki diz: Out 23, 2010. 9:37 AM
OK so if you do Nick a primary winding, would it be correct to think that you can repair it with carefully placed solder ?
Teslaling diz: Nov 14, 2010. 11:04 AM
DON'T SOLDER IT!! YOU WILL BURN THE ENAMEL OFF THE SURROUNDING WIRES!!! THAT IS REALLY BAD!! Seriously, if you nick the primary wiring too bad, its better to just get another MOT! A small nick can be taped up with electrical tape, or covered in glue, though.
fgleich diz: Out 21, 2010. 8:13 PM
I have first hand knowledge of a guy getting killed by one of these capacitors because he did not short out the terminals and drain the charge out of it. These caps contain a lethal charge and can KILL.
Bob_144 diz: Out 16, 2010. 9:18 PM
I scavenged a transformer weighing in at about 25-30lbs for the core weight, would someone be able to tell me what AWG and the turns to make this into a welder?
fishnfreak18 diz: Out 7, 2010. 3:11 PM
would the transformer out of a golfcart charger be enough to use by itself for a welder? and how would u wire it?
seoer2010 diz: Out 3, 2010. 7:24 PM
The author of a book about the Nike Ken Griffey Shoes children are the subject of WE's 'Raising Sextuplets,' filed for legal separation from her Ken Griffey Jr Shoes husband, Bryan, earlier this month after his arrest for domestic violence in Arizona. Masche is seeking sole custody of the Cheap Ken Griffey Shoes couple's children.According to court records, Masche filed the petition Air Griffey Max 1according to his Facebook page.
xz586 diz: Set 24, 2010. 6:21 AM
charlieb000 diz: Set 16, 2010. 3:08 AM
why is there no DC rectifier in your circuit? (do note you will need a large number of diodes to cope with the current, and will drop the output power by a bit), i thought it was better to DC weld...
evza134 diz: Nov 26, 2010. 6:45 PM
from what i understand and have been told by my boilermaking teacher, its almost always better to stick weld AC that way you avoid arc blow.
11richie21 diz: Ago 26, 2010. 5:27 PM
hello I recently read your Instructable on how to make a welder out of two microwave transformers. So I went ahead and made a diagram from reading it, I just wanted you to take a look at it and verify that I did this right! Thanks =) comment back soon!
sakimoto diz: Ago 24, 2010. 6:45 AM
how can you tell which side of the transformer is positive or negative using a multimeter?
tinstructable diz: Nov 11, 2010. 2:50 PM
my multimeter will tell you a negative voltage if the polarity is incorrect... and analog multimeters the needle will move backwards from the starting point.
jackie46 diz: Ago 14, 2010. 4:56 AM
just question wondering if u could put air regulater and plasma cutter head on here make it work
oddelyodd diz: Dez 21, 2010. 3:04 PM
I dont think so; there isn't enough voltage to ionize the gas, here is why:
the voltage coming out of the transformer...the amperage is there but the voltage isn't; you would need a bigger core to wrap the same sized wire to get the right voltage/amp output
also, the output of the transformer is ac (you need dc to use as a plasma cutter) unless you could rectify the ac into dc with a REALLY BIG rectifier or lots of medium sized rectifiers to supply the needed amperage without blowing up the rectifier (quite literally)
and last but not least: you would need some sort of high voltage pulse to start the arc between the electrode and the thing to be cut
onkelf diz: Ago 9, 2010. 6:01 AM
would it work with a triac regulator ?
MACKattacksnipe diz: Ago 6, 2010. 1:15 PM
Global Warming is a Myth you crack heads
abadon diz: Ago 7, 2010. 4:35 PM
true that!
jumpup_dnb_dj diz: Set 20, 2010. 11:46 AM
No it's not.
microedit diz: Jul 14, 2011. 11:53 PM
Global warming is true, but only 1 degree higher every 15 years....Discovery Channel...
zfolwick diz: Ago 5, 2010. 8:06 PM
I was only able to get 18 turns of naked copper and it looks like a rat's nest. This is hard enough I'm going to look to purchase my other transformer somewhere... What's the other wire? 8 gauge?
0087adam diz: Ago 2, 2010. 2:29 AM
I think you need to check your math a little bit, your equations are off. But other than that the concepts are the same and i applaud you for figuring this all out.
natcrazz diz: Jul 29, 2010. 12:26 AM
Can I use only one transformer if I intend to weld only thin metal for small jobs and artistic purposes?
clayfigur diz: Nov 24, 2010. 4:38 AM
make a spot welder, use bigger wire, lesser turns... its ideal for thin sheet metal..
use a copper or carbon rod instead of welding rod...

I am also thinking of making one my self... already have 3 stick welder and a migwelder.. I need to make a spot welder for thin sheets...
eprobe diz: Jul 13, 2010. 4:45 PM
Step 2 is where you'll run into trouble. You cannot remove the secondary windings without destroying the whole unit. I tried it. I chopped, cut, drilled and finally bashed the copper out. Took one hour and I was only half-done w/ one unit. The copper is jammed and epoxied in place, totally impervious to anything short of TNT.
fast400ex diz: Jun 24, 2010. 11:59 AM
First of all, I would like to say PROPS TO YOU for this awesome project; I really want to try it. But I have a couple questions. If 10 gauge wire like, what is in an extension cord? (Bare with me, kind of a newbie) so this welder requires one outlet plugs, correct? Would it be possible to add more transformers for higher amperage? Do you strip the ten gauge down to bare solid copper? And you wrap it where the original smaller wire was right? Also, in the schematic, how are the existing primaries connected to the new 10 gauge windings? Okay, so I think I’m figuring this out a little better, connect the original windings together and connect the new windings together so it is two long lengths of wire? And connect the negative of the one outlet plug to the smaller wire guage winding and the positive to the larger? Or what? Sorry I am just slightly confused by the wiring. sorry if I sound like an idiot here, but I would appreciate a response because this is an awesome project I want to try.
fast400ex diz: Jun 24, 2010. 12 PM
also, whats the final output? and would there be a way to change it? like a large potentiometer or something?
fast400ex diz: Jun 24, 2010. 12:49 PM
a finished product schematic would be great
maxpush99 diz: Jun 23, 2010. 5:04 AM
It would help if you try to have the 2 windings in resonance. after you remove the secondary windings you should weight it. you then use the same amount of copper by weight in your new winding,\ Just calculate lenght by thickness or weight the new windings good luck
jamisan91 diz: Jun 17, 2010. 7:10 PM
hey could I use 12 gauge
DIY++Dave diz: Mai 10, 2010. 5:22 PM
I made one acording to the instructions but it won't arc. If anyone can help please leave leave a comment.
jules15 diz: Mai 10, 2010. 3:48 PM
So, you wire the transformers in this so they step down the voltage? Because you want a lot of amps?
jules15 diz: Mai 10, 2010. 3:44 PM
my microwave is 120volt. cant i just use a 120 socket with one transformer?
Billdo22 diz: Mai 7, 2010. 3:05 PM
is it 120v or 220v? no offense but you dont really tell us out right, or maybe you do but i cant find it.
hobbles diz: Mai 2, 2010. 7:33 PM
Hi im just going to be welding some thin walled aluminum tubing could you use one microwave transformer for this or do you still need to beef it up with two?
Sun+Gear diz: Abr 24, 2010. 5:10 AM
ok. so i was welding and my second transformer started to make a high pitch buzzing sound. so i turned it off to let it cool. when i turned it on it did the same thing and it pushed up the secondary coil. is the problem in the primary or the secondary?
smartrobot diz: Abr 10, 2010. 10:10 AM
 On Amazon you can buy 2 microwave transformers  for $30.00
Snerdguy diz: Abr 9, 2010. 6:43 AM
I understand how your welder works. But, it is clear that many of the readers do not understand the dangers of electricity. No one should attempt this project without a basic understanding of electricity. The 38 volt secondary may seem harmless. But it has a very high current and kill directly or cause severe burns.

The set up in your photos should only be used to demonstrate the principle. A truly practical welder needs to be encased in some kind of grounded metal cabinet. There should be thermal cutout on each transformer. If much welding is done, they will heat up considerably. There should also be a fuse in the primary in case a transformer shorts out. Otherwise it could catch on fire. I also suggest installing a fan to cool the transformers. This will increase the service life of the welder.

Another practice I would suggest is to only use this welder on a GFI protected circuit. Should something cause the primary windings to short to the secondary windings it might save the life of the user.

There is a reason why commercial welders have the extra parts in them. They are for the protection of the user and the machine.
tristantech diz: Abr 23, 2010. 6:49 PM
I agree. More safety features need to be included
XOIIO diz: Abr 8, 2010. 7:10 PM
Very Nice.

Also, Paul's video is gone.
wbsbadboy diz: Abr 8, 2010. 12:05 PM
Pictures 1, 2, 5, and 8 are not loading.
Would you please check them and repost if needed.
Thank you very much.
cvbritton diz: Abr 8, 2010. 6:31 AM
 Preparing the transformer. You didn't mention the two 'Shorting Blocks' of laminated iron that are wedged into the spaces of the core. These protect the microwave magnetron tube from a possible overload condition. We don't worry about that here. Try knocking these out with a hammer and punch. It won't hurt and it MIGHT give a bigger output current. 
chad2.o diz: Abr 3, 2010. 10:49 PM
when i test the transformer is it suppose to get hot because when i test it the primary gets really hot

VanUnamed diz: Mar 20, 2010. 6:48 PM
I've made it with italian 220V transformers, i winded 2mm cable 24 times to obtain 19.4V each transformer. 2,5mm is the diameter including the rubber casing

thanks alot for the idea
oasiac diz: Mar 16, 2010. 3:41 PM
Can 1 microwave transformer create a hot enough abrupt flash to make a small tack weld.  I only need a small weld for what I'm doing.

I'm building a marble roller coaster for my engineering class and I just bought a large spool of some kind of metal wire used for chain link fences.  I simply need something to make a small tack weld.

And if I connected the original microwave capacitor to the circuit would that work for a quick jolt to make a small weld rather the long consistent arc?

close/-----Trans.-----Capacitor-----welding wire-       -clamp-----/close
Tobita diz: Mar 17, 2010. 5:13 PM
Most of the time, chain link fences use galvanized steel, the zinc coating is dangerous to weld. I think (yeah, that's my plausible claim of ignorance phrase.)
jlipimpski diz: Mar 19, 2010. 9:27 PM
Good god, no, do not do that. the capacitor is rated for a much higher voltage than what you have coming out of the transformer, and even then it's a really really tiny amount of capacitance. your setup would not work.
jimboa2020red diz: Abr 24, 2010. 9:52 AM
i'm hoping to make my 18V cordless power tools wall powered. I have a smaller microwave transformer (115Volts ?) along the with the hv capacitor (labeled 2100 WVAC 0.74uF ?) The transformer works with the tools but is a bit week (yes, properly using 50V ac-dc converter). Would it be reasonable to incorporate the hv capacitor to reach 18v-24v, or will I open a worm hole or something (over kill voltagewise?)  I have a multimeter, but clueless as to how to use it.

Also, how would fully I gain this know how, as an electrician or something? Online is very complicated and lengthy.
jlipimpski diz: Abr 24, 2010. 1:44 PM
uhhhh... well. ok so any way you go about this is going to be long and lengthy. Basically what you want to do is take 115 Volts AC and transform it down to 18 V AC, from there it goes into a bridge rectifier (or a full-wave rectifier if the transformer is center tapped), and some filtering capacitors. But, you're going to need some pretty robust things because tools pull a lot of amps... ok. So, I can't really tell you step by step how to do this, and it does sound pretty... well, ridiculous. Read this:

and poke around in that site. you'll learn a lot.
Hubiewan diz: Mar 14, 2010. 6:43 PM
Hubiewan asks, have you tried three transformers for use with thicker rods?
punkhead58 diz: Mar 13, 2010. 8:54 PM
Electrode holders always looked like straightening irons to me.
ampeyro diz: Mar 13, 2010. 7:13 AM
so if mine is made for 220v(europe) and have near 100 turns too, i will ned to make the secondary with 10 turns?
MrV diz: Mar 13, 2010. 11:49 AM
no, the europeans have twice the windings on the primary(200), so you should wind  20 turns.
msw100 diz: Mar 8, 2010. 11:09 AM
Surely DC would be better
forced_membership diz: Fev 24, 2010. 12:54 PM
I'm super stoked to try this, but I'm having a hard time finding the donor microwaves around here without driving an hour away or buying them from Goodwill.  Where are you guys getting your microwaves from?
DIY++Dave diz: Fev 27, 2010. 8:11 PM
If you have an appliance store nearby you could ask them if they have any junk microwaves. I just got one from my local appliance store just a few days ago.
Hubiewan diz: Mar 16, 2010. 10:47 AM
Salvation Army pays to get rid of microwaves that are damaged and, won't sell.  I got two for free.   Hubiewan
theRIAA diz: Fev 3, 2010. 6:40 PM
WOW, just finished testing it out. I welded some bolts together and a bunch of things to some angle iron. This thing works way better than I expected, it can slice right through thick chain if you aren't careful.

I used 12 ga solid core wire and it worked out perfectly. You could use stranded but fitting it in might be hard. After each turn I used a flathead to compress the new turns flat inside.  One thing I changed was using 33 turns instead of 20! This gives lower amps (less deep cutting power) and higher voltage (more spark distance). I was concerned it would be underpowered but it's anything but that. I have the microwave fan cooling them down but even when that wasn't hooked up they never got too warm.

Iv'e only tripped the breaker once. When I attempted a 4" line using a whole 1/16" stick at once. I'm very happy with how this thing turned out.
Black+Ninja diz: Jan 27, 2010. 4:27 PM one of those rotary dimmer switches which are used for dim lights work for welding thinner metal?
theRIAA diz: Fev 5, 2010. 11:36 AM
nope, tried one I had laying around. It kinda worked but then it started smoking... You need one rated for at least 2000W
Sun+Gear diz: Mar 14, 2010. 6:46 AM
what if you hooked it up the primary coil (a.k.a. incoming wires from outlet) would that have the same effect?
Black+Ninja diz: Mar 14, 2010. 7:37 AM
that was what I was thinking to do
theRIAA diz: Mar 14, 2010. 9:47 AM
That's what I did but it wouldn't matter. My transformers converts 120v at 20A to 60v at 60A, both are the same Wattage, around 2kW.
dylanz333 diz: Jan 24, 2010. 1:27 PM
 I've just completed mine, and it is AWESOME!  I saved so much money. Thanks, you guys are geniuses!
dylanz333 diz: Jan 23, 2010. 2:34 PM
Is it possible to run a 110v line for each transformer?  Just like your schematic, but in the end it would be 220v total?  If this is possible, can I connect them to a standard wall outlet? (one plug over the other)
jeffreywong diz: Jan 13, 2010. 12:23 AM
Can anybody tell me how much the maximum current for a microwave transformer can carrying? If I want to rewind a 12V to 240V, 25A for 12V side  transformer , izit possible to do that?

riku1 diz: Jan 12, 2010. 3:03 PM
this is sweet my gpa just taught me how to weld last summer and iv been tryin to find an arc welder instructable i can afford 2 make
when i make 1 i will post how well it works diz: Jan 2, 2009. 12:35 PM
I'm not really good at electronics, but I'm trying this anyway - worst fear is not electrocution but rather hooking it up the wrong way. Reading the comments made me even more confused.

I live in Europe with 230V, and the microwaves also run on 230V.

- Is the schematic correct?
- How many windings of 10 gauge would I need on either secondary?

Hope I'll get an answer, it has been a bit quiet with the responses here, lately.
PyromaniacDaniel diz: Abr 8, 2010. 5:55 PM
you can connect the sets of wires into one plug. for yours your diagram will work because you have almost twice our voltage here. In fact you probably could get away with only one transformer unless it overheats.

The point of the transformer is to lower the the voltage and increase the current. Vi/Ni=Vo/No and Ii*Ni=Io*No where V is voltage, I is current, N is number of turns, and i is input side and o is output side. He said his was getting about 38 Volts open current so make one loop and test the voltage output. Use the equation above to determine the number of loops in the primary. Then determine the number of loops you need in your secondary to produce a voltage of approximately 38 volts.
PyromaniacDaniel diz: Abr 8, 2010. 5:57 PM
that should read "38 volts open *voltage*"
kf diz: Abr 9, 2010. 6:51 AM
when your microwaves are for 230V then wire same like the "US" version in step 5, parallel at the plug and in row the welding side. (the transformers for 230V have already double number of winding on the primary compared to 115V)
Also hooking up wrong is not a big issue, it just doesn't work as the output voltage is then near 0V.  Change from one trafo the primary (propably black/blue wire) , should help

Xellers diz: Abr 30, 2010. 2:54 PM
No, your schematic is not correct and it will not work. The two transformers need to be wired in an antiparallel configuration. This means that the primaries need to be in parallel, not in series. You need to do this in order to put the secondary voltages in phase, otherwise, they will be a full pi radians out of phase and will cancel out. Good luck!
robot797 diz: Mai 17, 2010. 9:15 AM
well it is easy use the normal scematics

if the output makes 230 and the trafo needs 230 it will work

ps bevore you kill the mods make some sparks
just for the hell of it
Garik_axper diz: Jan 1, 2009. 5:04 PM
In the schematics you have 2 electric cords that plug in the wall outlets,but here you are running the primaries parallel to one wall outlet . Am I missing something ? BTW thanks for this Instructable, you guys are geniuses :)
jonathandirtbiker diz: Dez 22, 2009. 9:47 PM
Okay well im confused so  how do i wire the transformers to the wall?? Do i use the existing plugs for the transformers?? Does it matter which way the windings are and hoe does all this wiring work???
La+Rotta diz: Dez 18, 2009. 2:17 PM

First of all, thank you for this instructable. I'm working on it right now, but I'm locked at step 4. Unfortunetly, my 10 AWG wire comes with an very thick PVC isulation, and is impossible to wire it on such small space. The store where I bought it stole all my money, so discarding it is not a good option.

I had an idea: Replace the old jacked (white) with a new one made of electrical PVC tape, as shown in this example

Do you think it's enough for avoiding arcing or shorts?

PS: This "new method" would be great, 20 or more turns would be easily placed

pyromadness diz: Dez 4, 2009. 2:06 PM
this is to anyone whos made this welder for uk 230v mains. How many amps does it draw? (max 13 for me) and is there are fuse in the plug to the wall? (or will it just keep blowin?) TY
pseudoki diz: Dez 4, 2009. 4:22 AM
 hi sorry if this is a dumb question but ive searched every where and i guess im the only one curious. but is this supposed to be an AC or a DC type of welder?
and if its an AC welder is there a way to convert it to DC?
Skullking1323 diz: Dez 15, 2009. 4:56 PM
it's an AC welder. if you need to DC weld there's an instructable on how to do it with car batteries.
twenglish1 diz: Nov 18, 2009. 2:56 PM
is there any way i could figure out what my current output is?

i would really appreciate the help
La+Rotta diz: Dez 18, 2009. 2:27 PM
 Yes, check this out

look for the photo showing the blue plastic cofee can, near the end of the page. The text below it is your answer

tonhe diz: Nov 12, 2009. 6:54 AM
If I am concerned about blowing the breaker (using 115v AC here in the US ~15amp) would using a 3rd transformer help? I assume it would lower the voltage further and raise the amps up, but as far as welding goes, I'm not familiar enough to know if that would help.
twenglish1 diz: Nov 18, 2009. 3:01 PM
stick welding is mainly about the amps, the higher the current(amps) the deeper the weld will penetrate into the metals being welded. so you will want lower currents for thinner metal and higher currents for thicker metal.  voltage is another important part of stick welding, because if you don't have a high enough voltage you will not be able to start/maintain an arc, i believe you need at least 40 volts, thats what my microwave welder was and it worked good.  and i just measured the output voltage of my 240v AC stick welder(max output is 225 amps) it puts out about 80 volts
classiczippo diz: Nov 10, 2009. 3:16 PM
i made one a few days ago its pretty sweet but i moded the vice grip  insted of holding the wire in the jaws i took another welder and just welded the wire to the vice grips now me rod dont fall out like it did befor and idk y it cap falling out
timmy300 diz: Nov 8, 2009. 2 PM
Hi guys. im from the uk. i want to use two MOT's for my welder, but i dont undeerstand how to wire them up correctly and safely. Ok so in everyones elses MOT arc welder are the transformers with in series to each other or in parralel? How to i connect all the primary wires into a 13amp three pin UK wall socket?
I havent got my MOT's yet but does anyone know what kind of current i can get out of 10 turns of thick wire on both transformers with an input of 230v @ 50hz? Also i heard that somone used 10awg wire and it melted can anyone recomend a good thickness and a supplier?

clayfigur diz: Nov 27, 2010. 4:16 PM
if you have a 3 pin wall socket... the third one must be a ground wire... connect the earth wire/ground wire to the casing of your MOT welder....

Its better to make a welder, using thicker wires on the secondary, even with lesser turns.You just need to add another transformer..

I tried 2 transformers, 10AWG 10 turns each... secondaries in series, primary in parallel.

then 3 transformers 8AWG 7 turns each... secondaries in series, primary in parallel. (this works better)

I'm also thinking of making a 4 transformer welder, as soon as I find one more...

Anyway, as added cooling, i used the fan found in the microwave, to cool of the unit from heat. a little aluminum heat sink would also help..

microedit diz: Jul 14, 2011. 11:47 PM
About the three is ac electricity always on, the next is used only if there is a short to it... i.e. bad wiring....the third the government added for the housings of appliances, so a short would not get to a person touching the appliance. But ...a double short would still get you (very rare!). Also, the second wire is necessary to complete the AC circuit but never has juice...its just a conductor (unless a short).
dph84 diz: Dez 14, 2011. 9:37 PM
Note: I gave voltage for the U.S. by mistake. In the U.K. the voltage in the uk is 230, but the real distiction to be made is that it is 50hz instead of 60hz.

Frequency change affects transformers like this: raising the frequency (more than the nameplate value) causes the transformer to "fight itself" more--i.e. more heat, due to less effeciency...though this is not considered unsafe as long as it can be dissipated. Lowering the frequency, on the other hand, causes the transformer to "not restrict itself enough" (to understand that one, take an AC power class...) thus causing TOO MUCH CURRENT to flow through the windings themselves... which can cause meltdown. Its not simply a heat thing, though it becomes heat. it is an overcurrent thing.
dph84 diz: Dez 14, 2011. 9:42 PM
The first prong is the "hot" conductor, which represents one end of a single-phase "edison style" power distribution transformer out at the street... the second prong is the center tap of that transformer...(it has 240v overall, the center tap is a difference of 120v, and when you use both "ends" of the transformer out at the street --both "hots"--it gives you 240v.) The only reason the second prong does not "have juice :?" on it is because it is connected (bonded) to the third prong--the bonding electrode conductor--at the breaker box. Effectively telling the power distribution transformer where ground is. However the second prong DOES "have juice" during half of the cycle of AC...Its just that it has no potential to ground because they are the same point, provided you are close enough to the point where they meet. The bonding electrode is to give a low resistance path back to the breaker box in the event of a short, in order to trip the breaker--but you can and do get the living daylights shocked outta you before the very SLOW tripping of breakers occurs. That's why breakers are there to prevent fires, but GFCI protected circuits are to protect personnel. Just wanted to get that all corrected. Thanks :)
The+4th+Doctor diz: Nov 5, 2009. 9:08 PM
Thats the exact variac i have, got it on ebay for 55$ with shipping
rada194 diz: Nov 4, 2009. 5:07 PM
Does a regular oven have the transformers
MACKattacksnipe diz: Nov 4, 2009. 2:18 PM
i like the lase welder in the ammo case but i would put a bigger switch on the outside and a bigger fan so it looks nicer
CKalash diz: Nov 4, 2009. 1:26 PM
I pulled apart a newer microwave and my transformer looks nothing like these, is made with a plastic casing, and is connected to a circuit board.  Can I still use this or do I need older model microwaves?
cvbritton diz: Abr 8, 2010. 6:26 AM
 Newer microwaves use 'Inverter Technology' which uses a switching power supply instead of the 'brute force' transformer. The smaller transformer outputs the same power but runs at a higher frequency. It WON't work for this project. :-(
jonahsmiley diz: Mai 10, 2010. 10:41 AM
Roughly how old does a microwave have to be in order to have the right kind of transformer?
cvbritton diz: Mai 10, 2010. 12:37 PM
 'Inverter Technology' microwave ovens certainly haven't 'cornered the market' yet. Many current (and cheaper) models still use the 'brute force' transformer. My experience (here in the US) is that not many 'new'  ovens will be found in trash piles or 'thrift' shops. Inverter models will likely 'brag' about their energy efficiency. Come to think of it - I expect that the Euro-Brit markets will be converted well before those here in the energy wasting US.
(we have oil to burn!!!)
timshapiro diz: Jul 27, 2010. 10:21 PM
Sounds like this is a dying technology in Microwaves. Are there any other products that tend to have the same sort of transformer?
archer1232 diz: Out 24, 2009. 7:01 PM
Do you even hook up the green ground wire to anything on the transformer? I dont get it. :/
TimAnderson diz: Out 24, 2009. 7:38 PM
green goes to the cabinet. It's not supposed to carry any current. It's just there so a a loose wire that touches the enclosure will blow a fuse instead of giving you shocks.
archer1232 diz: Out 25, 2009. 10:54 AM
So basically you are just hooking up two wires to each tranformer(positive+negative)
DirttrackinRedneck diz: Mar 12, 2010. 7:44 PM
It wouldnt be a bad idea to hook the green wire up to both the transformers so no madder what you do or wat happens they stay grounded.   
HSPrzepa diz: Ago 27, 2010. 7:07 AM
should the green be hooked up to both cabinets? and a cabinet is the transformer right? lol
microedit diz: Jul 14, 2011. 11:54 PM
About the three is ac electricity always on, the next is used only if there is a short to it... i.e. bad wiring....the third the government added for the housings of appliances, so a short would not get to a person touching the appliance. But ...a double short would still get you (very rare!). Also, the second wire is necessary to complete the AC circuit but never has juice...its just a conductor (unless a short).
philmcclure diz: Jul 8, 2012. 8:54 AM
I hate necro'ing threads, but I have to respond to this. In the U.S., the three prongs are hot, neutral and ground.

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.

Easymkay diz: Ago 4, 2012. 10:08 PM
This is an interesting issue to me: just ground the chassis vs. the chassis and the x-former cores in series vs. ...go even further and INVOLVE the ground in the circuit, like this guy implies: Personally, I wont have a metal "chassis" to ground, out of healthy respect for the overall energy unit will be entombed in wood. That doesn't mean shorts couldn't arise elsewhere. This contention might be moot in cases where a salvage home electronics input cord has a ground less sturdy than its own main two leads, which I've seen in all manner of home electronics...but not in my case because I'm making sure the ground in my project is fatter then the Romex gauge in my girlfriends wall [not my house] where I will christen this beast. BTW, huge fan. "Tool shed full of reality"...sublime.
grimgroper diz: Out 22, 2009. 4:05 AM
this looks like a great build a welder is much needed...

...but wouldnt it make sense to put the secondary coils in parallel to make more current? or are we not looking for 2 much current?

great instructable btw 
sthealthraider diz: Out 15, 2009. 9:27 AM
what rod ur using?
sthealthraider diz: Out 15, 2009. 9:23 AM
What 2 plugs!!??!
rcguymike diz: Set 24, 2009. 6:40 PM
how much voltage do you get out of microwave transformers? I'm thinking of using one for a jacob's ladder or tesla coil. a few KV would be convenient.
twenglish1 diz: Nov 18, 2009. 3:06 PM
with the voltage doubling action created by the capacitor and diode connected to the transformer while its in the microwave you will get about 3000 - 5000 volts
Kamikosis diz: Set 18, 2009. 5:29 AM
What about in the UK where there is 220V? Should I just use one transformer?
zeron-79 diz: Set 9, 2009. 11:28 AM
THANK YOU SO MUCH! the cheapest welder i can get around here is 500$ and i have some microwave hangin out
arkfusion diz: Set 6, 2009. 6:03 PM
I used 12 gauge. is this going to make a difference?
ferball diz: Dez 6, 2010. 6:35 PM
I used 12 wire 10 was two thick to get enough windings. Idid melt one coil when my rod stuck rewound and it added a fan to my enclosure and pay a little more attention and no problems. 12 wire makes for less of a "duty cycle".
applegeek diz: Jun 14, 2011. 6:34 AM
I suppose it would just make the duty cycle shorter. I've been thinking about using 12 AWG myself because I know I can find lots of unused Romex cable with 12 gauge wire in it.
jefftecklenburg diz: Set 6, 2009. 5:14 PM
Hello The microwave welder is great. The two main reasons, everybody said it won't work and it welds great, they could not believe. A few tricks, when winding the secondary. use wire with THHN insulation it has a higher temp rating, and the nylon coating makes it easy to wind the coil. Problem is it cost me 15 bucks. If you think ahead you can use the wood grain case of the microwave and make the welder box, also use the fan in the microwave to cool the transformers. This is great thanks alot. Next step is on off switch with power on light and a control pot.
stasterisk diz: Set 9, 2009. 10:43 AM
Awesome!! post photos if you have some!
inserbot diz: Set 23, 2009. 7:37 PM
Stasterisk, any suggestions on how to build it using 220V microwave oven transformers on 220V (not 110V transformers on 220V, as it's suggested on step 5)? Should I use the same circuit, or is it different?
aaawelder diz: Set 5, 2009. 9:38 AM
I thank all that have built my welder and those that are under construction. The link above ( Build A 70 Amp Welder ) pointing to the AAAWelder site, is no longer valid. My new address is: where everyone is welcome.

Randy Gross, aaawelder
thomas6149 diz: Set 4, 2009. 7:53 PM
I built one similar to this with two pairs of transformers in parallel for double the amperage. One pair had an off on switch and the other pair was controlled by an incandescent light bulb dimmer switch to control the output. If you plug in each pair and they growl, it is out of phase, reverse the input wires on one transformer. If the two pairs wired together growl, reverse the output wires on one pair.
tollef diz: Set 1, 2009. 6:13 PM
Be Positive?? Be ConStructive??? Are you KIDDING?? This is Basic science at work, but it is STILL like Magic !! I am SO impressed !! (Yesterday, I was so Frustrated !! I was so sure everything was right but - no weld, just a few weak sparks. I had thoughts of Buying !! Horrors!!) Out of phase? Today, simple switch of wires on the primary coils, voila !! When I first got this 'done', I took it to work to check the output. Wouldn't you know, that was the day the electrician at work spent all day on a welder that was down (plus, I think he thought it was just plain dangerous; never got to check mine). There were quite a few comments about blowing fuses, someone getting hurt, etc. Today, it was a little 'sticky' at first, but then, a nice thin bead, twice. Then a friend of my son tried it. He couldn't believe you could build a welder from 2 microwaves and will now be looking for a couple of them. This opens up SO many possibilities. I am SO thankful you posted this project and I found it. I want to build bikes, shelving, a garden gate, telescope equipment, more. REALLY, this is impressive, saved me money, and every now and then I need a success at something, like this. Christmas comes each year. Building my own welder, having it finally succeed for the first time is much more rare. Superlative instructable. Well done !! For the record, Tollef is my son. I used 12 gauge wire instead of 10. I have about $20 in it. Everything ran fine. Nice smooth bead. I used 5/64" E6013 rod. Again, Thankyou !!! Onward and upward.
sharlston diz: Ago 31, 2009. 12:21 PM
will spokes from a bike work for a welding rod?
Tombini diz: Set 4, 2009. 8:43 PM
No, they have no flux in them... But maybe for fusion welding
sharlston diz: Set 5, 2009. 12:43 AM
you could add flux
Tombini diz: Set 5, 2009. 6:11 PM
Yeah, you probably could using fusion welding with an oxy/acet I don't know, only experimentation will tell...
aaawelder diz: Set 5, 2009. 9:46 AM
Only with a shielding gas and plasma torch, in other words, GTAW or Tig.
mattameo213 diz: Ago 20, 2009. 5 PM
The is another instructible that claims 10 microwave transformers are needed, what makes the difference? does the other just have more power?
mattameo213 diz: Ago 19, 2009. 4:43 AM
I'm going to try this. Thanks for the instructible.
Guerreiro diz: Ago 12, 2009. 8:09 AM
Hello to all, I'd like to know if I can upgrade my arc welder (a small, cheap one), with this method. What I mean is: if I Wind a larger copper wire in the "transformer" would it work? Thank you Miguel Guerreiro
Guerreiro diz: Ago 10, 2009. 1:37 AM
Good day to all, Could you please informe me if one can upgrade a arc welder with this method or a symilar one ? Thank you Miguel
ddc1011 diz: Ago 7, 2009. 4:48 PM
How do you tell if a dimmer is solid state and rated for inductive loads. I have checked the website of leviton which is a manufacturer of dimmers sold at home depot as well as the packages and cannot find any references. Thanks
TimAnderson diz: Ago 8, 2009. 9:07 AM
This $20 harbor freight "router speed control" is the best deal I know of for a dimmer that works with inductive loads. I bought one to use with the welder, but I haven't tried it yet.
Pagano's hardware here on Alameda has lots of dimmers, but the ones that do inductive loads are $40 or so. The packages there say whether they are intended for inductive loads or not.
tditulio diz: Out 17, 2011. 10:29 AM
Used this speed control. Tested with a 34.4VAC on full. It does vary the voltage readings under adjustment, so I would say it works. Haven't welded with it yet however.
sir+bobby diz: Out 24, 2011. 9:26 PM
When you do weld with it can you post your results here?
tditulio diz: Nov 4, 2011. 10:45 PM
First let me say, I have never welded before. This is my first hands on experience.
The box only goes to 15 amps and you will be blowing a lot of them at first. Probably run a 20 amp fuse with no problems. I ran a 30 @ 75% and it started to work properly, then the transistor in the box blew up. Upgrading this or decipating the heat from it will need to be done to go above 15 amp fuse safely. Also, one of the transformer secondaries smoldered, so I need to replace the wire or re-insulate it to have this welder work again. This was probably due to lack of proper heat decipation.
ronmaggi diz: Ago 7, 2009. 10:42 AM
Wichard sells Wichinox for the removal of ferrous material from stainless steel. In West Marine it is kept with the sailboat hardware. I don't know where other chandleries keep it. After welding your stainless it is a good idea to re-passivate the stainless with it as welding will expose the iron in stainless steel.
lenny25 diz: Ago 1, 2009. 1:57 AM
Hey guys I need some help from the experts. I have acquired my microwave transformer, and rewound the secondarys. Now here's where it get interesting. I stay in South Africa, and we have 220v, 15amps coming out of the wall. So I figured with so much wall power I probally only need one transformer. So from what I understand, I will be putting 3300watts(220v*15Amps) into this transformer. Another interesting detail is that I think my transformer has 200 turns! I put 16 turns on the secondary (although there is space for more, I just don't have a piece of wire long enough). Which means that my out put voltage will be 17.6v, and 187Amps! Ahhhhhh!!!! If I wind a few more turns on the secondary, I could probally squeeze 25 on there, that will bring my output voltage to 27.5v and 120 amps. Which seems like quite a lot? So here's my question: Will this work? If not, and things go bad, what will happen? I don't really want to destroy my transformer, because they are really hard to get here. South Africans won't give you snow in winter. I had to buy a broken microwave!
tokooloshe diz: Ago 1, 2009. 2:57 AM
Hey, that's interesting. I'm in South Africa too and I just found this instructable. I will try to get some more information.
lenny25 diz: Ago 1, 2009. 4:16 AM
Cool, I'm in Cape Town, where are you?
tokooloshe diz: Ago 1, 2009. 12:06 PM
Cape Town, northern suburbs. Been a DIY addict since I was about 5.
lenny25 diz: Ago 2, 2009. 7:36 AM
Hectic! Me too, I'm stay in Burgundy Estate near Richwood, been tinkering and building stuff as long as i can remember. It's the most awsome hobby, I'm especially interested in building stuff from recycled stuff and making my own tools and machines. Nice to meet you. My name is Lenny (go figure). Yours? Where did you go to school?
lenny25 diz: Jul 29, 2009. 5:29 AM
I take it that the output is also AC? Yesterday I tried out this dinky little welder, that plugs into an AC wall socket but converts it into DC power for welding. It welded so beautifully, striking an arc was puts, I could not get the rod to stick if I tried! Any ideas of how one could DIY something similar, perhaps modify this welder somehow? Would be nice to have something to plug into the wall. I don't have any battery operated tools, because I never have the foresight to charge them before working on projects :)
kikiclint diz: Jul 17, 2009. 12:36 PM
I have been trying to do this, and used 12 guage wire, and it overheated and melted the secondary coil into a huge chunk. I think I got 14 volts per transformer with the space packed as well as it could. I am retrying with 8 guage wire and it only gets enough coil to get 5 volts per transformer. I wish I had some 10 guage wire. At my current rate, I could use 6 transformers, and only use a small portion of the power on each. Either that, or I could theoretically get a couple of hundred of amps at the correct voltage, and melt my wires still .
BOOJAN diz: Jul 7, 2009. 8:35 AM
I want to build mig welder, but i have problems with the transformer, so can i use the transformers that are used in this Instructable???
xBrainstormerx diz: Jun 17, 2009. 5:08 PM
what if the wire isn't insulated is it okay if wired it up anyways just respond somewhere above or msg me at
xBrainstormerx diz: Jun 17, 2009. 4:58 PM
So uhm I don't think I'm getting this does the primary connect to the secondary at all?
stayputnik diz: Ago 5, 2009. 1:13 PM
Nope. In a transformer, the primary and secondary windings are completely separate circuits. When a current runs through the primary coil, it produces a strong electromagnetic field that induces a current in the secondary coil. Same concept the makes generators work (magnet passes by a coil) and radios as well (coil in the transmitter connected to an antenna produces an electromagnetic field, which is picked up by the reciever's antenna causing a current to be induced in its own coil). RFID uses this concept too... th