DIY Spot Welding Machine

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How to build a Spot Welder with a microwave oven transformer. Never connect the transformer to the grid before removing the secondary coil, because it produces 2000 Volts at 500 mA, this is LETHAL. A secondary with more turns than primary rises the voltage. On the other hand, a secondary with less turns lowers the voltage and put more amperes to draw. With a thick cable we make a 2 turns coil that delivers 2 or 3 volts and many many amperes. This is why the cable has to be very thick.

[@kenw.1112]

This is a excellent video on making a spot welder . Thank You! I have repaired microwave ovens for over 30 years . A cautionary note for anyone who is going to take apart a microwave oven for parts . There are high voltages with LETHAL CURRENT present inside microwave ovens. No Exceptions be sure microwave oven is unplugged and for extra safety short the magnatron high v. capacitor out. It has a bleeder resistor but do it anyway. A guy down the street opened his broken microwave to attempt fixing it. He reached inside and was electrocuted died on the spot.

[@pikudopikao8425]

You know, in short time the capacitors just discharge by themselves but yes, it is very dangerous.

[@husse843]

U repair mickrowave for 30 years now ?????

[@stoneisland1000]

@@husse843 I'm laughing

[@tinkmarshino]

that is good advice but what does the magnetron high voltage capacitor look like and where is it? Also how do you discharge it?

[@FragBenitez]

I just read this after dismantling a broken microwave oven, fishing for the transformer. Guess I'm lucky, but yeah I got a little cautious when I saw a big capacitor inside, thought to myself "I should have discharged that". I work with CRT monitors so I know this can be lethal.

[@Benoit-Pierre]

I had read several welder tutos; I always found them a bit complicated for me; here, you show a very easy method, and I will build it very soon.

[@mirosawbuczynski4152]

To doskonały film na temat tworzenia spawacza. Dziękuję Ci! Od ponad 30 lat naprawiam kuchenki mikrofalowe. Uwaga ostrzegawcza dla każdego, kto ma zamiar rozebrać kuchenkę mikrofalową na części. Wewnątrz kuchenek mikrofalowych obecne są wysokie napięcia z LETHAL CURRENT. Nie ma wyjątków, upewnij się, że kuchenka mikrofalowa jest odłączona, a dla dodatkowego bezpieczeństwa krótki jest kondensator o dużej pojemności. Ma rezystor upustowy, ale tak czy inaczej. Facet na dole otworzył złamaną kuchenkę mikrofalową, żeby spróbować ją naprawić. Sięgnął do środka i został porażony prądem, zmarł na miejscu.

[@MysticalDork]

be very careful if you use the first method because you can easily damage the enamel insulation on the primary and cause a short circuit to the core. Paint the part of the primary that was in contact with the core with some nail polish or similar, and use a sheet of card or plastic to ensure that there are no shorts.

[@tinkerbit]

OK. Thank you!

[@p0k7lm]

grear advice on paint insulation , i once used plastic clear coat , but under abnormally high temps its not so good.🔧🔩👍

[@panikkosmakkoutos7173]

8

[@milankral5891]

Lak to nezachrání. Tenhle návod nikdy nedělejte! Životu nebezpečné! Najděte si jiné video, toto je zatím to nejhorší, co jsem kdy viděl. Autora by měli uvěznit.

[@tinkerbit]

Removing the transformer shunts increases the available power but introduces a risk of core saturation and overloading the primary.

[@Roccoo]

this was a great video! lots of useful info here and i really enjoyed it! now i want to make one.

[@GRAHAMAUS]

Have you done any tests to see how thick the metal can be and still make a good weld? I have an old microwave transformer - might give it a go myself. A nice touch would be a microswitch that turns on the primary when the jaws are closed (safely insulated of course).

[@jakenbaked87]

If you do two in series, you can make a stick welder. If you attach a RMS current regulator and high current diodes, you get even better results.

[@sangalgojojijoe3463]

what do you eat every day??.very amazing..thanks a lot for sharing this knowledge...

[@Nabo00o]

woa i didn't know microwave trafos had magnetic shunts! I guess there's a reason they are such a popular item, the shunts makes them practically short-circuit proof just like a welding trafo, perfect for happy experimenting!

[@user-ug7ju1pd4z]

Good morning in Thailand, thanks for showing me know

[@tinkerbit]

A copper alloy used for electro erosion electrodes. Is has cobalt and other metals also. Very conductive and harder and higher melting point than copper

[@Miata822]

Wonderful ingenuity! Thanks for sharing!

[@eugbug1]

Microwave oven transformers are great for projects because unlike some other transformers, the core is in an 'E I" format. So the 'I' limb can be removed easily. I made my new high current switch mode power supply (20A DC) using a re-wound microwave oven transformer. After cutting the core I clamped the 'I' part back on using two steel plates rather than re-welding. They're great for use as powerful electromagnets also. The primary can be run on low voltage DC with the secondary removed. A suppression diode should be used on any switching circuitry to protect semiconductors or contacts of relays.

[@milankral5891]

Také jsem zkoušel zdroje postavit, zejména nabíječky a nikdy se to neosvědčilo jako když jsem si precizně navinul svoje spočítané trafo z originál plechů. Tohle má ohromné ztráty - i naprázdno je odběr okolo 3-4 A. Dá se to sice zregulovat elektronikou, ale ty ztráty jsou tam pořád. Jediné uspokojivé použití by bylo jako booster - pro krátkodobé použití k nastartování vozidla. Ale musíte použít pořádné 100-120 A diody + chladiče.

[@sergeismd]

Все гениальное просто , спасибо

[@two_number_nines]

what would happed if i add turns to the first winding so it reaches half of the max possible windings volume, then remove the iron between primary and secondary and then fill the remaining space with 6-7 mm cable?

[@tinkmarshino]

This was interesting.. but where were you twenty years ago when I could have used one of these... Thanks for the share... Merry Christmas!

[@tinkerbit]

20 years ago I was preparing for my future and beggining working. And after that I could afford to do things I like like this in my spare time. Merry Christmas for you and your family too!

[@p0k7lm]

great job 👍 , tnx 4 vid ! when i build mine i will try using carbon rods for electrodes .⚡gringing the core is the way to go instead of cutting apart the valuable useful copper secondary, as for the buzz core sound ( not anoying ) it indicates its powered up .⚡🔩🔧👍

[@radumotisan]

very nice! this could prove useful, and using wood seems a good approach

[@tinkerbit]

The shorter the best. If you see pro spot welding machines photos, they have the electrodes very near to the trafo. My example has too much cable. If I had to use it a lot, perhaps I would shorten it.

[@FeCr3]

Excellent! Harmless 2 or 3 volts of voltage output. But massive amps...

[@tinkerbit]

Thank you!

[@pedroventuracalos2513]

muy buenos videos amigo, una pregunta que numero de cable es el que usa porfavor,,, saludos

[@antoniosantangelo8759]

Ciao di tutti i video che ho visto il tuo video è il migliore in assoluto per il fai da te perché sei di una semplicità strabiliante complimenti poi uno lo personalizzo come vuole Ma sei davvero brava a spiegare

[@hyparh]

The shunts are there for some current limitation so I don't think they need to be kept, especially in this case, when we need as high current as possible.

[@tinkerbit]

Secondary, the wire is much thinner. You can cut it with an utility knife. Do several cuts and draw the cut wires with pliers. Cut again and draw, and so on.

[@ismaelcosta8444]

tenho um trasformado q era entrada de 380 e saida de 220 tirei o segundario de 220 e rnrrolei fio mas esquentou muito porq ?

[@axelbelleris]

I like very much your idea! A prototype of soldering! I from Argentina. :)

[@MattsAwesomeStuff]

Aha, I spot my grind & clamshell MOT method. I'm pretty sure you learned how to do this from my videos, or ones like it :). Good job!

[@ErezAcker]

Thank you. Do you think a copper pipe will make (after corect shaping) a decent electrode? Or is brass better still? Thanks again.

[@dashuslab3316]

Thanks for the video guide, I've made one for 18650 battery welding

[@calcolson2813]

I made one from a microwave but I just can't weld battery packs worth a darn. One problem will weld one wouldn't. Dat one sided weld is not very good most time I almost burn a hole. And wen it seems like I'm making progress. I make a weld not a good one but a small start .I try to make another one. And nothing. I brush of the probes and I can make a one sided horrible weld. Den nothing. Brush of probes a one sided horrible weld. Wat can I do to improve.

[@linjari]

I guess you could do secondary winding from copper brake line with shrink tubing and put coolant flow through it.

[@larrybaker1205]

looks cool I will have to give this a try

[@kwstikas82]

hey, nice job there. have you tested the maximum thickness of metal plates this welder can weld?

[@patonova89]

What open circuit voltage recommend, in the secundary?

[@hewelgeduwelbeh7418]

What can a microwave oven transformer I replace the transformer UPS (universal processing unit)

[@stavdim5]

In what fuse have you connect in switch cabinet? 25Ampere, 35mpere?

[@user-jh5mh7rn8o]

P0

[@cscentoamore1]

Very good, what is the measure of this cable you used in secondary?

[@tinkerbit]

Perhaos around 100 if you multiply the horizontal number of turns by the vertical...

[@Jimbo78ify]

This has been done before taken from a user on Instructables... This is a simple hack but leaves no safety regulations or fire-control hazards. Adding some sort of temperature detector would be a good safeguard as well as a capacative field indicator in case someone's finger came too close to the contact. Very simple to do and only need a High Power Mosfet to switch of the Primary... One last thing would is to shield it, ( Magnetic Field, any metal on you is a path to ground).

[@RNA0ROGER]

Don't you risk overloading the input when doing this or does the transformer current limit.

[@marceloclaudiocampos1277]

muy bueno gracias por su enseñanza amigo

[@qaisarawan93]

nice video I tried to follow along with it and bought a used MOT, the seller connected ac voltage to the primary winding (thin wire side). And it created humming sound. At home I removed that side and when I connected ac to the secondary side it created smoke and smell and became very hot to touch. Seems like the Secondary was already short? What you say? Also Now can i rewind it using suitable size enameled wire? Will winding it with slightly thinner wire be ok for spot welding?

[@alonsoberrios2968]

hello good video .... and a query to regulate current and amperage contienua about 20 amps? you need?

[@josesimon4557]

El hilo está recubierto de una laca aislante con lo que no tiene por qué haber ningún problema. Supongo que ese papel blanco es para proteger más y para que encaje bien y no se mueva. Siempre hay que actuar con sentido común. Esto está pensado y dimensionado para un microondas y no para un soldador, con lo que deberemos estar bien atentos que no se caliente. No es para un uso continuado o industrial sino más bien entre casero y experimental.

[@tinkerbit]

Thank you!

[@raynerguerra5471]

Hollo, do you know the current for the primary with the secundary in short circuit.

[@Mr.Neko013]

This most likely has been asked, but I'd like to know how strong are the welds? I've been wanting to build this, and now I need some spot welding done on my car's front end for a part that is spot welded in that needs replacing. Will this be strong enough? It's for the radiator core brace

[@jeffreydeutsch7336]

Try it on a couple of pieces of scrap of about the same thickness. Nobody can predict what your transformer and your wire and your tips are going to do. Make a test weld and try to break it

[@amankumar-kr6rr]

this is fantastic this program.

[@UberAlphaSirus]

No, the primary, the mains side, has to be rated at your outlet voltage. the secondary, the output side you can do what ever you want with it, it will not effect the primary as it is set to give a set amount of power thru the core. However the secondary is your own design, so you could over do things on that side.

[@fluchterschoen]

Tune in next week to find out how to build your own coffin & incerator...

[@arthureleclair29]

+fluchter1996 ,,,,,how bout' it,,,joker........LMAO......thanks.....

[@Appregator]

😂😂😂😂

[@blancohoussam6128]

hi man good video if i want to make homemade arc welder which works 10VAC, then how many coils do i need for the secondary circuit ? thanks

[@benuitraalte]

This is the best preform video ever I saw on KZbin ! Just found exactly what I wanted to see! GREAT JOB!!! good discription no bullshit no intro no nonsens AWESOME !!

[@carlosluzandre475]

MUITO BOM OS EXEMPLOS E OS CUIDADOS, BASTANTE ESCLARECEDOR DAS UTILIDADES DO TRAFO DE MICRONDAS

[@moseskh8477]

can i use this method for diy arc welder? 2 turns with big wire?

[@jeevankumarreddyravuru8710]

what is the specification of transformer required to generate low voltage high current power supply (shock proof) power supply to make spot welding machine please tell me...

[@MultiSilverstreak]

Please tell me the specification of input and output current

[@SVAROG-FREE-ENERGY-COM]

Very very good job my friend 👍

[@zvarkovethebest5019]

Thanks so much for the genious idea

[@aaronwest2511]

Just a quick question, what would happen if you didn't put the metal shunts back in?

[@jimu57]

Thanks. I found it. Have you tried smaller wire such as #6 or #8 and using more windings? Or do you think that is not going to produce enough amperage? thanks.

[@vzarou]

hi why you need to cut the steel i took the first easily and i saw you outing small pieces each way why on the top secondary line

[@copo7205]

why did you leave the primary instead of the secondary? It's got way fewer loops -> less current transfered to the thick wire

[@enoc24]

hello I'm doing grant the machine you have in your video such as heco beam which does not have much power but I must be conectralo 220 v instead of connecting on 110 v the label says it must be connected to 110 v but as you remove the secondary transformer do not know if this changes or if I put thick cable is very thic

[@johnal4560]

made one but ii get short circuit and it blows the fuse when u connect the power to the transformer does it matter which one you connect the black wire and in which one u connect the

[@javiergonzales8487]

What Circuit is being used to power the transformer when the spot welding is being performed ? Direct connection between the Transformer and the power strip ?

[@mikec1182]

Would booster cables work as second winding?

[@salceti]

how do I know which is the primary and which is the secondary? When you say you cut out the secondary did you do it with a grinder?

[@dans4270]

Can anyone explain to me hoe electricity it getting through to the connectors? The wire is isolated and not touching 🤔

[@neehaglee7249]

Totally Amazing! Damn Good! Thanks for sharing this most wonderful video. :-) Lots of effort!! Kudos to your patience :)

[@Nexfero]

very informative keep up the good work

[@tinkerbit]

Thanks!

[@maxwang2537]

Thank you. I’m going to make one of these.

[@tinkerbit]

No, I haven`t. Since the distance between the tips is very short and the iron plates to weld are thin the resistance is low so I think you dont need more voltage. You needs Amps.

[@tinkerbit]

I would get less current and that means less temperature at the welding spot.

[@elmakednos]

I have seen your video and yes I did the same thing. I would like to ask you this: I did not put the shunts, instead I got 2,5 turns of cable in the secondary. Some people say put the shunts and some not. And I am asking anyone who knows why to put or not to put them.Are some reasons for it?Shunts are from several of mettalic shims, but they dont touch the transformer frame because they are covered with tape.

[@oodimvale]

good....good...Thanks.....São Paulo - capital - Brasil

[@user-mq6gq1iz8l]

What is the output voltage and how many amperes are used at the input?

[@SarjanaTutorial]

mantap mas tutornya,, moga bermanfaat, semangat

[@rabelad]

Very clever! Thank you!

[@tinkerbit]

Look up "American wire gauge" on Wikipedia. There is a table. For #4 gauge wire it fuses at 94 6A for 10 seconds. I connect it less than 5 seconds. And yes, it ends hot.

[@giampieromurgia6962]

Bravissimo ... che idea geniale! 5 Stelle !!!!

[@tinkerbit]

+giampiero murgia Grazie!

[@tinkerbit]

Because the big amperage is only at the secondary circuit, this is in the thick cable. The primary is at 230 V and perhaps 10 A, so the circuit breaker doesnt flip. The secondary is "isolated" from the primary, this is called galvanic isolation. The circuit breaker "feels" what happens with the primary, but knows nothing about what happens to the secondary.

[@vzarou]

what size of yelow wire can we use 2 metal nails ???

[@jackac3394]

You never stated what gauge wire you used for secondary (?).

[@MrPhillerup]

Great spot welder!

[@antoniocarlostiburciodecar7069]

good afternoon!!would it work for you to use the primary of the other transformer, as a secondary of the transformer you opened? in that case it would be 220v input and 220v output of the transformer, what do you think?

[@ErezAcker]

hi great vid. what did you use for the electrodes? thanks.

[@rayner1guerra]

Hello, do you know the current for the primary with the secundary in short circuit.

[@marionnepatrick7383]

sir, whats the significance of putting the shunts back in the reassembly?

[@bta24600]

Estou tentando montar uma dessas, mas até agora só tive tempo para reconstruir o transformador...

[@CheckEmGG]

NIIIICE!! what gauge wire did you use for the secondary?

[@Mudtiresrc]

Would this work to spot weld aluminum?

[@1marcelfilms]

240 turns primary and 2 secondary would be good enough?

[@andrelfalf]

Incrível como é fácil de fazer

[@seepoowoop]

Awesome I did a 12v one for input and it gave me 45,000 volts!!!!!!!

[@nomanwadood3117]

when i was removing mot secondary winding i damaged the primary winding of mot could you tell me how many turns and layers required in mot primary winding plz reply there is no answer of my question on internet.

[@tinkerbit]

The main reason is that I am Spanish and my English pronunciation is far from perfect. Other reason is operative: in order to make a good sound a voice over is needed. Even in my own language is not easy to speek. When we see TV newsreaders we usually think that it is easy, but when you try the results are too much different. If you want you can see and hear me in Spanish in this youtube channel: cienciabit I am trying to improve my diction, intonation, diction, etc, .... but it is not easy.

[@alextrombogosy293]

I understood , im Brazilian and i have the same problem

[@RyuunosukePanda]

The best you can do is look up "How does a power transformer work" Hope this helps.

[@kernel_data_inpage_error]

What voltage can you get by feeding electricity to the secondary?

[@akarboard]

What gauge cord (yellow and green)did you use?

[@everafterinkable]

Where do you get the primary, secondary part your taking apart? What did it come out of?