DIY Spot Welder, Attempt #2 with Microwave Transformer, Failed!
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- Опубликовано: 22 апр 2019
- Attempt #2 (Failed) at building a spot welder. My goal is to spot weld the tabs of my lithium battery cells to the copper bus bars. You can check out some of my previous videos to see more about the battery.
I've taken apart an old microwave to get at the transformer inside. Then I coiled a 1 gauge copper wire inside the transformer. However, I'm not getting any spot welds. Perhaps I blew the circuit board attached?
I'll keep everyone informed as I go. If you have any ideas why this didn't work, please let me know.
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/ davidpoz
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Some advice: 1. secondary coil: make a thick cable with thin insulation so you can make 3 loops to get about 3V. Voltage is very low, you do not need that thick insulation, also it is bad for coil cooling. 2.Do not use aluminum and use copper electrodes. 3. Try make cables as short as possible. 4. Remove magnetic shunts between primary and secondary coils if you did not remove them yet.
Why use copper cable and not aluminium? Can you tell me the difference between them? What will happen?
@@TheRealObamagaming copper is more conductive than aluminum. Been 8 months but figured I'd answer lol.
The little board is just a high frequency filter to filter out signals from the magnitron. There is no need to connect this to transformer. Thanks!
I've taken 5 transformers out of 5 microwave ovens. They are all different sizes. The one you have there is definitely a big one. Erich from New Zealand
3 feet of 8 gauge wire from Lowes with 5 wraps in same direction as primary windings gives one volt per turn (transformer law). Voltage goes down 24 times while current goes up 24 times giving around 70 amps at 5 volts. Mine works like a champ. An on/off light switch to make and break the circuit; couple of copper welding tips at the end of your secondary windings ground or filed down .
The circuit blew because when you turn on the transformer while spot welding.. it not only draws a
inrush but also draws a constant current of 25 amps thus blowing the circuit board attached .. it is better if you connect the transformer directly to mains and also more turns are required for more voltage and better spot welding.. use copper wire
I used 2 AWG copper wire with thin insulator and it worked fine. I also bought a cheap spot welder controller that cost about $14-$17 so I can control the time better to protect the 18650 batteries. I also think your wire is too long. To what I have read, you need high current to weld. You have 3 things you have to work with --VOLTAGE, CURRENT, RESISTANCE. The less primary Voltage, & less Resistance= high AMPs.
Hello sir!! Again, as i did recommend in the first video, you should get cooper or brass bars to do the spot welding, aluminum is not good for it, also reduce de gage on secundary cable can be 3 instead of 0, connect the primary directly to the voltage or get some control but as of many others videos I watched about it don’t need it, hope you can succeed on your welding project 😎👍🏼🇵🇷
A success is measured by many failures !
We always see successful projects without knowing how many attempts they've gone through. Its good to see the challenges too.
I’ve seen others figured out that it takes voltages between 9 and 20 and currents of 250-350 amperes to work. 20-40ms in duration which depends on thickness of the material
It's kinda cool that you can see the pieces move from the sheer voltage. gonna attempt this myself to weld chainmail, and I hope I don't electrocute myself!
I made a lot of mistakes making this. Try two wraps in the secondary instead of one.
@@DavidPozEnergy Invaluable for other people like me looking to make a spot welder. Now I have a better idea of what not to do!
You have a great little channel too by the looks of it, subbed.
Greetings
I have my own successful experience and after several attempts:
I used a 35 mm square wire with the plastic wrap removed and the shrink tube in place. I got 3 laps in the front and 4 in the back! And a secondary voltage of 4.5 volts. Addition of a timer circuit breaker. Currently, it is used with batteries with a timing from 0.1 seconds to 0.4 seconds, depending on the thickness of the nickel
You dont need that board. Get rid. Just try through the momentary switch for now. Then get a spot welder 100a controller from ebay/aliexpress. They have adjustable pulse time and current and wire straight into the transformer. You do need a 9-12v AC, yes AC psu though.
Transformers step up or step down AC voltage according to the winding ratio. If you have 10 coils in primary and 20 coils in secondary coil then you will double your voltage. Half as many in secondary coil as primary you cut output voltage in half. Gauge size of coils basically determines current. But even if your secondary is fat gauge, you are limited by primary coil gauge size. For voltage, think about a mig or tig welder.... typically 20-40vdc for steel and AC for aluminum. You are probably looking for 50A+ as the required current but you'll need a controller to fire the transformer for a fraction of a second or you'll melt battery tops. If you need DC output you'll have to source some high current diodes on the secondary output. I can't speak specifically to the voltage/current requirements for welding batteries I've never done that. I'm sort of thinking with just one winding on that fat output cable, your output voltage is likely much too low.
Base your assessment on the wattage. Originally a small M/W was 500 W and a big one 750. Then came 1200 and 1500 Watt. That is the cooking power. The total wattage of electricity consumption is of course more.
David, the secondary voltage should be under 10 volts if you’ve put 1-2 turns in the transformer, which is about all that will fit in most frames from microwave ovens. Good luck!
Keep trying... You will get it! I'm thinking about building one, I'd I was you I'd get the timmer board from Amazon for this, its programmable, where the lenth of pulse and current can be adjusted, it also requires a 9-12 v AC supply it uses as a clock signal, or something, I'm planning to get one, and use 10 gauge wire with thinner insulation just double it , a few times to get 8-12v and a few hundred potential amps, the spot welder board works on the ac side with a triac, to adjust things, I just couldn't find a 9- 12vac supply, I guess I'll have to order that also, or wind a transformer, with the timer board you will basically have a professional spotwelder!!!
I would get rid of that little board and try some smaller wire thru the transformer. About 5 or 6 turns might work.
You could remove that circuit board apply current straight to Transformer with switch
U r right.
interesting attempt. I would say you need to use more copper laden wire. lots of insulation there. teflon coated 3/0 fits nicely. triple the amperage of that " 1/0 " you have there. it will not get nearly as hot as your version. not easy to get in but... its worth it. you can use the flex stuff to connect once your outside the winding area.
Saw that years ago in Morher Earth News (iirc).
you can sort of seize the transformer by looking at the wattages is uses
As a scrapper, I can tell you that you just have to drive around a bit on garbage night and you will find 5-10 of them for free.
One big problem you have to solve yet is to get repeatable turn-on times - maybe want to have a look how Marco Reps did it in his video "Quick DIY Spot Welder without microcontroller"?
I think u got the Neutral & Ground, or Hot & Ground input leads instead of Hot & Neutral. Not sure, but I've seen this 64+ Volt crap before. My extension cord was only giving 64+ Volts, but the socked measured 120 Volts. After messing with the cord a bit (unscrewed the end caps, & looked at the terminals), & tightening it up a bit, it was back to 120. No clue what was going on.
Bummer! 🤷♂️
you can also use two pieces of smaler diameter wires, with thiner isolation,and wind it same as it is one piece. and this is better,because,to get mowe power from secondary, it must be filled with wire as much as possibile.i used two pieces of 4 mm wire(about 25 mm2 together) and wind it paralel,on a much smaller transformer about 8,5 x 7 cm.i got 2,2v with 3 turns in secondary. 2,1 v when short circuit,and wery powerful
Don't use this little limit switch to turn on the primary. It's not made to handle that much current.
one think to consider is to strip the thick insulation off the cable and substitute polyolefin heat shrink tubing. A more expensive solution would be teflon heat shrink. The temperature for shrink with teflon is around 250C.... polyolefin ~90C. working temperatures are well within limits for this application. (practically, start at one end and insert into the shrink tubing. as you slit the cable, slide the heat shrink over the bare cable. suggest leaving an inch or two at the beginning to let you completely strip the heavy insulation and replace with heat shrink tubing..... should solve the problem)
Spot welder with a single microwave transformer deliver about 50A: it's very good to weld lithium battery. Your cable is too long, try with a shorter one. If you need more power try with 2 microwave transformer and same cable (about 100A). Good luck !
Thank you.
I thought I saw that very microwave for free on CL not so long ago. :D
Don't give up! I see so many mistakes that you can learn from here; It feels like im seeing my past self. :)
First of u probably got ~2V and with that poor connection by the electrodes not much current will flow through.
I see people already gave you lots of tips.
All I can say is you gog what you need to melt all your stuff if you tweak some stuff
Thank god.. somebody that speaks..
I 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? Now can i rewind it using suitable size enameled wire? Will winding it with slightly thinner wire be ok?
It works better with one more winding on the secondary. Even if it is a thinner wire. I was too low in voltage with my setup.
@@DavidPozEnergy thanks for the reply. See my video the secondary of the MOT that we will be using as a primary for our spot welding has burned so entite transformer is stripped down. So i will be rewinding that as well.
Good day, sir. You are a very intelligent person. This is the first time, that I have observed, some one; intelligently, calmly, effortlessly and cleverly detaching the secondary winding from Microwave Transformer. Bravo.
I have seen Chisels being used, grinding the good welding off the “I”Core, some manually hack hack hack sawing ... and I’m like OMG.... no comments there! I’m extremely impressed. Let me watch the rest of the video.....BRB...
Thanks
sir is there a polarity in the transformer?
would of like to see how you did the wiring, thanks only one with some explanation, thanks
I was amazed at the interference created by the Pulsed Magnetic field on your camera....did you notice it??
You can make a spot welder from a supercapacitor
David you doing it ok but also you need to use copper points to make the contact and also take few seconds to weld the materia
I would say no, it's not the same that you would have gotten from a newer smaller microwave. I have seen flyback transformers in some of those.
If its an inverter style microwave, than different story.
But a smaller microwave will have the same size transformer.
Ive stripped a few diferent sizes and makes and models, and it looks like they all use the similiar transformer.
Hey David let me give You some advice. It is a while since I made my spotwelder from my microwave transformer. First, yes it is the same size as Yours. Second, my first build atempt was the same as Yours, my wire had the same thicknes but I failed. The spotwelder worked, but the spot weld was terible. I decided to rise the voltage on secondary coil by rising the number of coil turns (loops). I had used 10 mm2 wire (someting like 7AWG) and it gave me 5,5 volts on secondary. Now it is perfect, fine tuned for battery spotwelding. And last but not least I suggest You to connect tranformer primer directly to grid. You can control it with solid state relay (SSR). It will work like a charm, trust me. And last important information Im on 230V grid. From that implies, that You are to use twice as much coil turns (loops) to achive 5,5V on secondary, or just give him 230V like as we, europans do. :) Wish You luck my friend!
We are at a bit of a disadvantage with our 120 volt grid. So 5.5 volts on the secondary worked better for you. Good to know. Thank you.
The input inline board you are using is a line filter and fuse board, which you don't need. However, having a fuse is a good idea.
The transformer you have could have come out of a smaller microwave oven. The larger transformers are found in the early older ovens.
The insulation on that 1g wire is too thick for your purpose. You could remove the insulation and use insulation tape instead. It may allow you to get one more turn in the former.
Thank you.
What, was the capacitor spot welder to easy or just need another project. Cheers have fun.
LOL. I do love projects.
Plug the transformer into a multi box with a switch and just try the Transformer by itself
I expect others have mentioned this, but failing to discharge the capacitor, even in an old machine that hasn't been in service for a while, can be deadly. a big no-no in harvesting parts from a microwave oven
То
Время время и Маргарита кстати это там про своя правдаграмма время
I would remove a turn on the secondary. The less turns give you less voltage, but more current. Also get rid of the little board, but do use a 10 amp fuse.
Yo , el primario lo conecte directamente, lo hice para cogerlo con la mano. Utilice una tubería de cobre para agua, la aplaste y le hice forma de punta de flecha, el mago lo hice de madera, para proteger los cables y las puntas, en el centro puse un interruptor de los que saque del microondas, cortando una de las fases del primario, cuando lo acciono directamente, se produce la descarga de corriente, he soldado muchas, muchas veces y no me falla, lo utilizo para soldar las placas de níquel a las celdas de litio, al final he cojido el tacto con el pulsador, y me va de maravilla. espero te sirva la informacion.
But is that real that microwave transformer turned into welding machine
Exactly the same transformer as in small 13liter microwave oven
Use cupper conductors everywhere, forget aluminium, it has low conductivity also the same with tungsten. Cupper is necessity.
Also, throw away that regulator thing.
I'm working on my spotwelder. One full turn of 25mm2 cupper wire give 1.8v on open circuit and over 600amps during welding. I need to get at least one more turn into transformer. The voltage is too low. As it is now, I'm only able to weld 1mm wire onto something, and that takes about 10 seconds to do.
Thanks. I agree with you on the # of turns. This is an old video, but I had messed with it more recently and got better results with another turn, slightly higher voltage.
@@DavidPozEnergy I'm working on it now :) I changed the wire for copper strip - i bought strip of copper 15x0.25 and used 9 of strips per cable. it should have cross section nearly 34mm2. Then i got it into insulator and made coil. 2 full turns filled the transformer nicely, no longer is there gap.
facebook.com/peter.svancarek/media_set?set=a.3525864950775541&type=3 coil made from 9 strips (each strip has a bit over 0.25mm x 15mm). Current is not measurable (over 600A) and open circuit voltage has risen from 1.8(for one full turn) to 2.8V for 2 full turns.
Now it welds 1mm stainless steel wire in under 1 sec, 2.3mm stainless steel wire in about 2 sec, 4mm stainless steel wire in about 7-8sec.
Hi David that board is a dual hash choke and it has line to ground metal oxide varistor and one line to neutral for voltage spikes and a fuse. So it is not needed in your application except a fuse would be good. It looks to only have one full loop on the secondary you might get .8 to 1.9 volts on the secondary which is not enough. As for the transformers in microwaves it varies by the wattage of the appliance. Lots of newer models have a switching power supply instead.
"dual hash choke"... Thank you for directing my homework assignment. I'm going to look that up.
As for the voltage, you said it is not enough. What is the minimum voltage, and why? Thank you. I love learning about this.
@@DavidPozEnergy hash choke is the easiest explanation it cancels out induced noise from switching and from clock circuits like in the microwave. As for the voltage it works with the resistance of the wire and does the work in wattage output for example. What's best to use is magnet wire like what was in there but a thicker gage or multiple strands together. I built one a while back and used wire from a old tube tv degauser coil of several turns in parallel. More home work for you I guess.
When are you going the burn down the Workbench ? Take your time....do it right and upload the video...will be a learning lesson for all and fun watch....!!!
cut off insulation from cabl, redo with e tape wind 3 loops , eliminate pc board try again, dont give up.
I think this unit probably 20 amps primary coil that's why your room might blinking
How many turns for 12v and what's the number of wire
That cable is SHIELDED
Discharge that capacitor first thing !!
They can hold fatal charges for very long times !!
People DO die from touching them.
You should us this module
NY-D04 or NY-D08..... then you got it. cheers
The secundarry winding the ather way around
muchos equipos y poco cerebro.
Conecta directamente el transformador si la placa electrónica.
1) Isolation too thick
2) Not enough conductors inside that cable
3) U need 3 turns.
Yes it's the same size a Transformer
Thank you.
Lityum batarya yapıyorum. Güzel fikirler ilgimi çeker. TÜRKİYE
Copper contacts are needed! Aluminum is not good!
I saw the over head light go dim, while the switch was activated. Looks like you may have activated the Circuit breaker of your 3 Phase supply. I also think 1AWG , secondary coil is an overkill. What are you Spot welding, by the way? Front end of an Abrams M1A1?😂.
Lol, tank spot welding.
What is the name of the cutter u r using
I'm using a bandsaw from Harbor Freight. www.harborfreight.com/10-amp-deep-cut-variable-speed-band-saw-kit-63444.html You can usually find a coupon for it for $99, which is what I did. But the blade that comes with it is terrible. Here is an affiliate link to the blades I really like: amzn.to/33ET2Gh “As an Amazon Associate I earn from qualifying purchases.”
hello david i think you took out the wrong winding?
The size of the microwave doesn’t matter all you have to do is read the output and that will let you know the size of the transformer the smaller ones are 800 watts And then they just go up from there so technically you can find small microwaves with big transformers in them is it common, no but you cant simply just go by the size of the microwave also you want to use copper instead of aluminum the more conductive the metal the less it’s going to heat up because the electricity Is able to pass through faster. Think about taking a metal pipe and pouring a cup of boiling water through it with both ends wide-open itll get warm Now compare that to the same pipe with one end capped off with a just a pinhole and the end the water goes in wide open poor your cup of boiling water in there the pipes going to be scolding Same thing with electricity the current going into the conducting metal doesn’t change if it’s 1000 wayts coming out of the transformer it’s gonna be 1000 watts going into that metal but being slowed down Which causes it to heat the metal more copper is still going to heat up but nothing like steel I know you used aluminum which is the next best thing to copper but when you’re talking high current you want to go With the most conductive plus aluminum has a pretty low melting point copper has an extremely high melting point
I'd bet you blew the fuse on that board. just bypass that and send it straight to the transformer. you may want a larger switch though, as I'd expect you'll probably be drawing somewhat over 15 amps from the wall when welding.
Dont think that would be necessary its les then 5 seconds
Hang on is this going to be a series of "10,000 ways not to build a spot welder"? Apparently Edison was prone to that, good thing we didn't have YT back then!
I'm hoping third times the charm.
Try a old 12 or 24 volt battery charger...
You should use copper instead of alluminium!
EEh man please use 20mm wire with light insulation as secondary and at least 4 turns( you need at lest 3v to over come resistance and remove shunt core from transformer then you can eliminate current limit and also get more room for winding..... it will work i am binal from india
shepherd work I watched from Iraq that I thanked
That black line in the fuse may mean you need a new fuse
Right off the bat I would suggest you only use pure copper components which get exposed to the high current assosiated with the secondary coil. aluminum has a much higher resistance and could as a result get extremely hot. I suggest you use MIG tip electrodes for the actual welding tips/business ends. These tips can be mounted with steel hardware but you need to be able to put power to them with copper lugs or the like... anything else then copper will get very hot very fast, gets damaged and/or cause a voltage drop and lower current at you welding tips...
BTW: do keep in mind that the microwave oven may have had issues before it was drafted into welding heaven... 67 v where 120 v is due sounds like issues to me... just saying...
PS: check my video out on a butt welder I made with a similar microwave... works great, though I yet have to make a spot welding version... it welds chain mail rings like a champ though...
Also the momentary switch (micro switch) you use may not be rated for the 10-14 amps the transformer may draw... look for a pcb in the remains of the oven with a relay on it, switch the relay with a micro switch and have the relay handle the current to the transformer...as many have stated also: you don't need the filter pcb...
Thank you. I just saw your video. That's cool. How many of those rings goes into a suit?
Junk the board and go with a relay if you want to use the micro switch.
Do away with the little circuit board and just put the fuse inline w/ fuse holder and then just run the wires to transformer and then ground it and should been good to go....oh I always knock out the shunts I didn't see if you did or not.....I had one I ran with thick stranded 0 gauge....strands were bout 3/32 thick....beat the piss out of the copper wire with rubber mallet for a day or two trying to make it fit....it put out some wicked stupid current..
Did you find you need more turns? Some comments below are suggesting I need a little higher voltage, with 3 or 4 turns.
Actually at first I thought I did need more then I made some electrodes....well not so much making them but I used some might welding tips and filed them down to a point....there's better options but they did the job and I used the little switch you used but I made mine a foot switch and then I made some arms so I could really clamp down or put alot of pressure on what I was spot welding and the better your electrodes and the better your able to apply a good amount of pressure between the two electrodes the better the weld would be...but from what I could see about your wire was it wasn't as thick as the stuff I used.....it's like what they use at big transformers and whatnot.... I have the gloves that they would use when netting with the wire while out in the field with the wire....they are rated a 17K before they fail ....and the transformer I used I had to cut the base off and so there was a slight gap between the the base and E core...but once it's all working you should hear a ever so slightly hum while the transformer is running/ working.
Is it normal that my primary coil is smoking ?
NO. That's a bad sign. I ended up buying a spot welder. Too many issues with my attempts.
Guna wayer 16mm² atau 19mm² 3 pusingan
Lose the circiut board, you dont need it for what you're doing!
Just plug the primary directly to the source.
You are using AC current to spot weld. Try DC spot welding, you will have to use a bridge rectifier
Aluminium winding less then copper tolerance
voltage is too low you need to use more loop insade transfomer. now you have very much Amps but only 1-1.5 v and cabal is to long.
Well your insulation is too thick, and you left out the shunts between your windings. The point of spot welding is to create a short circuit with an arc. If you just "hook" up a transformer, especially to tungsten, you'll just get a short that heats up.
ERROR number one you used aluminum as electrode, and you didnt have to use the filter circuit from the transformer input it needs to run direct.
Thanks.
just 800w, I have the same one
Yes, it was 800 w, 120v MOT. '14 A' code was used for mfg no. lot no. or other but not really for the ampere.
David be careful that has a 3000vac output and it has a diode to make it DC . It only has a 400 MA output at that voltage. Remembe the MW is an Radio Frequency at a about 1200 watts. Not good for welding....You need a lower voltage and a high current. Like 10 amps out not input...
I thought it would only be that high voltage out the secondary coil, and I cut that out.
Wrong on every point. The transformer by itself definitely does NOT put out Radio Frequencies. That's what the Magnetron is for. Plus the Transformer does NOT include a diode. And by winding a couple of turns he has exactly what you say "Lower Voltage and High Current".
Sambung langsung pak....rasah nganggo pcb ne....marai ra jos..
Lilitane gantinan iu oleh power kongendi mas kok ISO metu genine
i told you to use Chevy starter solenoid (use the solenoid) and find a small cooper rod for weld tip. i promise its will work. Or any car starter solenoid. The solenoid is ignite the power. to the starter that's how it work. TRY IT.
You need 30 to 55v to start the spark willding including a 30 up to 200amp
You can use this volt to melting stuff
get rid of the switch and other crap just fire the transformer directly ( or by an normal switch )
Thanks.
just remove the board itself(keep the switch) the board isn't necessary at all
Kakakakaka vc usou alumínio pra fechar curto, não vai conduzir a amperagem, tem que ser cobre meu querido.
lmao aluminum electrodes
Awg 1 is equal to 25 mm`2
25 mm^2 is more like 3 AWG
Remove that board
he trying to connect a solenoid swhich , but that module is a filter.............
Dont use aluminum. Its not a good conductor. Regards. Also that thick insulation on that cable is gonna hurt your number of windings