Voltlog  

With a 35mm² AWG 2 wire, with 2 turns in secondary coil, I got 1.6v 522.4 A in my tip heads which are made of zirconium copper alloy. This alloy is the nessecary one to use in point welding machine cause of it's thermal resistance and conductance properties. I also use the 220v fan motor of the original microwave oven for cooling and one thermal fuse of the same oven and there is no heat problem so far. Fast and easy project. For technical calculations of anyone interesting have in mind.. How to calculate the output ampers? Use the equation : Is = Vp/Vs • Ip were Is = Amper of the secondary Vp = Voltage of the primary Vs = Voltage of the secondary Ip = Amper of the primary Now how to know the primary coil amperage is simple. Just devide your transformer given Watt number by the used voltage e. g. 850/220 = 3.8A (or for USA 750/120 = 6.25A) Also if you are curious about how to count the primary turns for other calculations the equation is: Vp/Vs = Np/Ns were Ns = turns of the secondary and Np = turns of the primary So following this equation you can for example find that the primary coil turns of your transformer is: Vp/Vs = 220/1.6 = 137.5 and for the primary turns you have to find the same number. So Np/Ns must be also 137.5 and that means Np/2 = 137.5 so on Np = 2 • 137.5 = 275 turns on primary. To ensure the calculations correctings just use the following equation: Vp • Ip = Vs • Is this means 220 • 3.8 = 1.6 • 522, 4 (approximately) is giving the same number. Correct!! Hope I help some interested. Have fun with your project and always take a really good care of the current for your safety!

Skip the hardware store for thick transformer wire and get a starter cable from an auto parts store. Also, put thermal fuse on primary since the secondary current can weld it "on"...

I made one of these, a bit more robust, years ago, but it worked well only a few times, maybe I can fix it, but I never needed. The electrodes I used are from "electrolytic copper". Thanks for sharing !

Super.Bune sfaturi . Am cumparat si eu unul. Conductorul este fabricat la Bistrita...RCB Electro !!!

Excellent instruction on making this - Thank You I will be making one with that particular PCB. Cheers

I think this is best video on spot welder topic.

Excellent project

Thanks for another great post, I look forward to watching them. great job!!

The problem is due to still high voltage. I made one with a thicker secondary cable that I've made myself from 0.9 sqmm EmCu. I have like 25 individual wires in parallel, 2 turns. Voltage is 2 V, but the current is very high. I still don't have the timing thing implemented, but I'm using it to weld other things than battery strips. Keep up with the good work

Cool build but I'd go with a tact switch instead of a pedal to lower the storage footprint haha. I love seeing how different everyone breaks out the probes

built my own thanks to your video thanks! Works great and I used 4x 12awg wire in parallel as my secondary with no issues. :)

hey ,i have to spot welders for battery tab welding,one is build around an MOT with a Crouzet syr line digital timer (the timer was gift from my father-in-law,cause it's very expensive for a diy project cost around 200 euro) a solid state relay to switch the primary,the second welder is build around 8 irf1404 power mosfets an arduino timer and i'm using it with a 450 CCA 12v car battery ,both of the welders working very well , i'm planning to do a video for both of them with a more detailed presentation and explanation

If the circuit is wired up properly the left knob control the current and the right knob control the timer, the tyristor(triac) is suppose to switch the secondary side, otherwise you would only need a 10amp tyristor. since 240v * 100a = 24kW

I like the idea of using the bought controller board and other parts to make it work more professionally. If I ever get access to enough batteries I'm tempted to make one using your design with some modifications to the arm build. I've watched several videos on this and yours is one of the best I would just like a more substantial design for the arm

Thank you Sir, i was looking for cooper diameter data for the transformer, you revealed it to me. Im so gratefull.

The sparks are due to the loos contact between the electrode and the strips. If you noticed the second weld at 12:31 did not spit out any spark. The spot weld pulse time looks a bit too much because the weld has burnt of some of the strip surface. It could be probably because of the first weld. During a spot weld there should be a firm contact and pressure in order to get the best weld and reduce sparking. I did not see any sparks when I tested mine.

I saved quite a few dollars by ordering 8 gauge jumpers, and then cut the ends off, cit both red and black into equal thirds/ 10 feet, lastly I stripped them and attached them to a secure point, twisting , it all came together like a rope. Now I have a perfect gauge that fits into 3/8 battery terminal lug. what kills me though, Advanced auto is crap compared to what it use to be! yo use to be able to rent or borrow automotive tools., I had to buy a terminal / lug press for 15 dollars . the hammer kind/ I still saved Bec.4 gauge battery wires go for over 30 Not MUCH THOUGH! unless i send back the lug crimper when done!

Your welds are not good as almost any other DIY MOT spot welders here on youtube. Welding time can be set to maxiumum 02 - 40ms(this is already too much time) because too much time will make burned nickel strip and welds will not be good. 01(20ms) will be ideal but for this you need 50mm2 wire. I use 35mm2 on my spot welder with 02(40ms) and 75% current settings for 0.10 pure nickel strip. My MOT is 700VA (its about 1100-1200W when shunts are removed). With 35mm2 i can get 2 full rounds - 1.5V and i can confirm its enough. I have bigger MOT (1750 VA) but dont have time to test it. I guess i will get around 2500-2800W with shunts removed. This MOT should be enough for 0.2 and maybe 0.25 pure nickel strip. Also the reason why your electrodes sticks to the welds is welding time - reduce welding time and electrodes wont heat up that much.

You can''t use the another secondary winding of the MOT because you switch the primary winding with the TRIAC. So until you switch ON the MOT with your pedal switch there is no voltage applied to the auxiliary secondary 9VAC winding of the MOT. The circuit doesn't work. You need a second transformer.

great build ❤

Thank you! very informative. I have made my MOT welder long ago with those old RU-vid diy post but not as informative as your video. I liked all the details that you mentioned that I did not have when I first did mine years ago. I may need to update my old one and your controller idea is great. I did not actually used mine because it seems like it heats up more than a blob of solder. It may be good on melting metal but not with li-ion batteries. I was not sure what to do with the magnetic shunt when I built mine so I left it in. I also heard that less turn means lower voltage --higher current. Also, tighter joints means less resistance =higher current. I checked those cheap controllers, and there's no instructions--great for pointing out to use 9v-AC. I saw some pictures that says 9v-12v but no specs that it can really handle 12vac. One of my problems long ago also was that both copper probes should make good and even contact to make better welds. It will also be great if you could give us the best adjustment timing that produces the best weld as you used yours. Your initial welding setting was set to 5-30, I know it may vary but at least an idea.

I had two of these red boards. one with a simple LED display and one with a black and white display. both didn't work. one time the soldering is too weak and the next time it's too strong and sparks fly. No adjustment made it better.but most of the time the Nickel sheet metal sticks to the poles

Hey you know what Might make a good housing for that. A filled box used to store ammo. I’m in the process of making one and decided that’s what I will use. If it turns out well I’ll show the outcome of it. Anyways great video.

Thanks for sharing your build! I think I need one now, haha

This is a rapidly growing area of interest, I build battery packs for myself and the Arduino welders and perhaps this one are better than the Sunnko. This is the most sophisticated for the price. All in well under $50,

Very nice explanation amazing, proud to be ur subscriber hats off 👏 👌

Complimenti per il progetto creativo 👍👏😁🔋

excellent video i was hoping to power it up- with a battery pack now i know why i can't thank you

Hello, can you use this board without the pedal switch and how? Regards

Thx 😊

I used this control. Getting 4v open cct voltage. Using aliexpress copper probes. Setting I am using is 4 ms? and 50A seems OK for 18650 tabs. Works well enough.

Very informative good job

Really nice work, dude!!!

I need to make the Welder please confirm to me is input Voltage to the transformer is OK to us 120 v.

Theoretical P=U.I= 230V.6A(max input transformer amps)= 1380W so, 1380 / 2,3= 600A(output) not taking the loses in consideration! so if you lesser the turns of your secondary so that you get a lower voltage, you get more amps!! Actually 3,5V on the secondary is a bit too high lower the turns and you will not need a thicker cable for the secondary...16mm2 can carry even the theoretical 600A in the short amount of time its seeing it even the insulation is enough. Try that!

what is the maximum amperes that the Triac support?

I only say u r a great person.

Great step by step explanation! Would it weld thicker stainless eg. 0.5+0.5mm ???

It give to much weld. I believe the foot pedal and or the board needs a faster cycle time, so if you can make that board cycle faster I would try that. Using the battery, solenoid and momentary switch, I learned the faster I tapped that switch the longer the copper contacts last and perfect welds. Even though they're both different ideas the time on allows for too much amperage.

I have an older microwave sitting under my bench ready for the task and would like to free up that space. I had no idea about the control boards. Hadn't even posed the question! But I don't have much LiIon battery replacements to do. :-( Maybe if I build it, they will come :-)

Great job!

How many amps you used for the controller board because i found 40a and 100a

I can use only 110V microwave transformer here. What needs to change to make a spot welder for 18650 battery packs?

I rewound my transformer with 4 gage wire and it puts out 4 volts will that be good

very good

Hola, interesante lo de remover las láminas del núcleo del transformador

Very good information sir.I am making a similar type . will you please tell me without current and timing controlling board is it possible if I use a little thin/thick wire and timing by pedal switch?

Thank you once again for the demo. I watched this video for the 2nd or 3rd time, because your descriptions are much better than many, I have observed. A few things to note here; is as follows, for your info and others. 1) The TRIAC heat-sink tab is electrically insulated. Therefore a good heat sink may be attached, using silicone grease, in between the HS and the TRIAC. 2) When you mentioned the auxiliary power to the electronics, you said, “ either 9 or 12 volts could be applied”. What was the actual power applied ? What company is ANG and what’s your local power supply voltage? 3) The electrodes you made, were sticking to the Ni strip and you said “ this is due to Electrodes made from normal Cu. I fail to understand that phenomenon, because, even after, Cu alloy electrodes were used, the Electrodes, were still sticking and fusing to PURE Ni strip. The reason of fusion is due to higher Amps. This could be avoided by reducing the Amps. 4) None of the links that was provided for parts and supplies, worked as it should be. I suspect this could be due to different location, from where the links were viewed? FYI I’m from United States. Please respond. Thanks regards and respects.

Please, the link is broken, can you write the amperes is the 9Vtrafo?

I wonder if tungsten rod for a TIG welding torch would work for your electrodes

i also did the same. But always my nickle strips getting hole, if not, get stick to electrodes. What will be the solution? May be high amps?

Thank you for your video and tutorials; and especially the safety warnings and advice .i will be attempting to recreate your spot welder.. keep up the good work and i look forward to more of your videos . 👍🏽

if can use a microwave transformer to make multi points spot welding

@Voltlog, Hi man, you should really do the 2024 version and elaborate on zero cross detection. There is much to review on the delivery of pulse to the electrodes. This is a great project to upcycle a readily available component. I am doing a 20S10P Li Ion pack so it requires extra long arms to allow comfortable access to a frame that is 400 x 200 approx I have the scorch marks on my wallet from sourcing the 18650's out of the USA Factor CAD to USD conversion, shipping, brokerage, taxes I think it was little under $1280 CAD, now add a quality BMS, shrink tube, and other, it's getting up there. Now I Have a background in LiPo batteries and have repaired many Dewalt and Milwaukee power packs but I am still a little sketchy on all the details of this endeavor.

Thank god for your post. I bought the same controller board but mine is a 40A, while yours is 100A. Now, my problem is, I accidentally smashed and destroyed my MOT's primary. (reckless me...) and my question, can I replace the primary winding wire with a different size, or should I find a new MOT? Thanks in advance for your answer.

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? Current winding is using 0.9mm enameled copper wire and the length and breadth of cross sectional area is 15 by 17 mm..

Your video inspired me to build a welder Thanks , I have a question , I ordered a 100 amp control board the Chinese one with one control and 3 segment display's it requires 12V AC do you think I could use a 15 V AC adapter ?

Why u use wood? Can i use metal tube quare?

Hi great work!! I have a question. Does the controller triggers the weld as soon as pedal is pressed or when you lift the pedal. I have a controller which triggers only when you release your foot after pressing it. Please let me know. Thanks.

nice build. What kind of fuse did you use and is that it in the clear plastic case on the brown wire going to the transformer?

Can you successfully weld 0.2mm nickel strips to the battery with this welder? Is there difference when welding 0.2mm PURE nickel vs 0.2mm nickel PLATED strips? This vid is among best explained DIY spotwelders!

I do some projects, working with 25 sq wire do 3 laps in microwave MD-701EMR-1 and not get good welding. I use NY-D08 Board and spot welding pen. Anyone have idea?

Hi, what are those four leds for? Can you explain.

Does 100a means the TRIAC output 100a?

Great job ,what about earth cable? Did U connected ?

Could you explain how you can make additional turns on the main transformer which Wil be powered through the board when you are gonna weld during the oftime there will be no current when you don't use it so it's impossible to power the board?? I am looking forward to your explanations about this iseu 👍

Nice

Will the timing module also work on 50Hz AC

Hi .Can you able to weld 2.0mm stripe with this ?

My DIY MOT welder can do 750 A at 2,5V or 2,8 open circuit, and it makes pretty good welds, I use an arduino as controler and build my own triac trigger circuit. I may make a video about it but will propely not be in english

Hello. I just subbed to your channel. Can you tell me, why you don't use a simple Switch?!

Awesome project, how much current does the PCB draw as I'm trying to work out what capacity transformer to buy

hi all .. is anyone else using a similar setup ? i just made it and the spots go red hot but not really perfect welds . i checked another video and according to him it might be less amps so i added another transformer . still everthing gets hot ( even at lowets numbers ) but does not properly weld . any suggestions @voltlog ?

there are two options for controller, 40A and 100A , what's the difference between those two, 40A one is cheaper

How much the voltage at the output of transform?

What thickness nickel did you use in this?

Microwave oven transfer watt??

What AWG gauge wire are we Yanks going to use? 25mm^2 ~ approx. 3 AWG. But all I see is THHN which, by definition, has both poly insulation and (clear) nylon sheath for abrasion resistance--which adds unnecessarily to the diameter. Is a poly-only or other thinner insulation wire available domestically? I don't see MTW in that size...

Hi and thanks for this excellent vid. I'm going to have a go at it and have already removed the secondary from my MOT. I've got the circuit board and the other bits are on their way. I've bought a proprietary hand held battery spot welding pen though. Will this be OK? Also, where is the very high voltage you mention? Is just from the triac to the primary on the transformer?

You realise that if you don't make full contact with the battery that shock is welding those gloves to your fingers instead!

What gage wire you using? And how many voltage you getting? Thank you

If I have 2 MOT's sitting here, what is the best configuration to utilize them both in this project? Primaries in parallel. 1 single secondary wound around one core then the other core? Or...?

Не нужна в таком слабом споттере регулировка мощности ! )))) Три трансформатора вместе...возможно ))))

it looks like you are pressing to hard on the cell while welding

several of your links seem to be dead

Se gaseste la Dedeman conductor pt aparatele de sudura.

nice!! 💪 👷🏻

I get 1.3volt output voltage is that OK?

Mey by transformer 12V 300mA??

Mai rezista?

The site said 100a would this be good for 4kw?

bro i cant find the transformer, any good idea.i need to buy one

why it is working?even you dont to conect the electroded to the outlet?

It may not be the cleverest idea to use a yellow/green wire for anything else than the so-called Earth connection (PE and PEN) read on here : en.wikipedia.org/wiki/IEC_60446#Protective_conductor

🍭❓What YOU THINK.ABOUT USING BRASS TIP WOR WELDING. J HAVE.💝👌👍

NO.

Great concept but show if they actually completed working model with the proper heat sinks. Items from overheating from continuous duty cycle. Advance to keep components: the case order the correct electrodes for doing the spot welding so you can actually show with a working model that RU-vid we can copy without danger

Great work on the welder and explanation of your design , today is the first time I have seen your videos and they are great ! like your other viewers have stated we don't need music sound effects or how to get it out of the box just the facts very often over my head when it comes to the technicals in the electronic components but it gives me great confidence to know all that stuff is in there haha, Thanks !

what size cable do you use?

I have been looking for a explanation of the way these boards work! Thank-you!