Spot welder recommendation


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Headrc

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Jan 27, 2018
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I have decided on pursuing a spot welder for my battery builds. What are the views about the alternatives for this in the $200 range of options for this need? Kweld? JP Spot Welder? Chinese? Which ones perform on not only nickel but copper. I have studied most of these but would like the end users input on these options ...or others if they are out there. Thanks, RH
 

daromer

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Copper wont work unless you put upp 10x that or more.

For normal nickel the 709A or AD+ is a good start. The 230VAC version that is because the 110 is weaker.

I have done some videos about it:

 

Headrc

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Thanks Daromer ...I have watched your videos previously and found them helpful. Your video's are the reason the Chinese welders are still being considered ...so thank you. When you say copper won't work, I assume you mean because of the voltage it will take?There is one that demonstrates doing some spot welds with copper. Here is a link to a video on it.https://youtu.be/G_JC4YGrvwA
 

jonyjoe505

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I recommend the maletrics arduino spotwelder, cost is 75 euros (93 dollars) just for the welder, you have to buy the probes seperate. I been using the older version since last year, the newer version is a major improvement but cost the same. He sells it off his malectrics.eu website, from germany shipping I got it in a week to california.

I built my own probe cables with 6 gauge pure copper welding cables, you need that thick copper to get all that amps into your probe tips. I use 015 nickle and get good welds at the low settings, the welder has plenty of power to spare. I been using a small 12 volt 28 ah agm battery to power it. The newer version you can use a 3s lipo pack to power it.

I heard too many reviews of the plug-in models blowing fuses, thats why I recommend the battery powered ones, but if you got good electricity thats an option. The battery powered ones might not look impressive because of there small size but they got plenty of power to get the job done.

With whatever tab welder you get, don't go cheap on the probe cables, I see many people using the copperclad audio wire for probe cables, those cable will get hot during using and they will jump around alot every time you do a weld. With the copperclad wire you will have to increase the power output of the welder to get good tabs, thats why the cable get hot. I was using 8 gauge copperclad when I first got the welder and the cables were too hot to hold after about 20 welds, with 6 gauge pure copper you can start and finish your project without stopping to let the cables to cool down.

At the endless sphere forums, they got some good threads on some of the different arduinotab welders. Another plus for the arduino welders, they don't take up much space.
 

daromer

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Headrc. 2 car batteries can supply many times more current than most normal outlets and cheap spotwelders running on AC can do. Spot welding a thin copper tab is easier than spot welding on copper wires or such that I thought was your goal :)
With that said it all depends on your end goal. My China version works great for spot welding 18650 cells and I dont have to bring up any car batteries or such.
 

Headrc

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The Malectrics is one that I am also interested in. As for welding leads ...I have already made some out of actual welding cable ...and some copper slate roofing nails. I got the tagged video below. Since I had all the elements to assemble what this video outlines, I tried it yesterday. First with 600 CCA battery ...which blew through nickeltabs as well as thin copper strips. I then tried a 330 CCA battery which did not have enough power to weld. I didn't have a battery between these two CCA's so I may get one and try that next. Even if it works I still may go ahead and get something that will give much more control as the control on this is simply how long you hold solenoid open. He stated he tried a digital timer and that did not work well.
 
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If you decide you want to spot-weld "fuse-wire" from the bus to the cell-tips (instead of 0.15mm thick nickel ribbon), you can use a LOT less energy, so the welder selection is less critical.

Nickel melts at 1500C / 2700F, fuse wire is very similar in composition to lead-free solder (mostly tin/zinc), and melts at 420C / 790F
 

Riplash

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Headrc said:
The Malectrics is one that I am also interested in. As for welding leads ...I have already made some out of actual welding cable ...and some copper slate roofing nails. I got the tagged video below. Since I had all the elements to assemble what this video outlines, I tried it yesterday. First with 600 CCA battery ...which blew through nickeltabs as well as thin copper strips. I then tried a 330 CCA battery which did not have enough power to weld. I didn't have a battery between these two CCA's so I may get one and try that next. Even if it works I still may go ahead and get something that will give much more control as the control on this is simply how long you hold solenoid open. He stated he tried a digital timer and that did not work well.

Hello Headrc.

I just built a homemade spot welder similiar to Daromer's. I used 4 gauge tinned marine grade battery cable for winding the Transformer, and used tripled up 12 gauge speaker wire to go from the transformer to the wand. With 120 VoltsI used 3.5 turns around the secondary of the M.O.T. And I am pulling about 340 to 350 Amps rms on the secondary. And about 16A through the primary. That works great for me hand timing the push button. If I need more power, I could add a half turn or another full turn to the secondary and it would get more power.

Before I rewound the microwave transformer, I tried Lead Acid batteries with a solenoid, and it worked, but you can fine tune the Power a lot more easily by adjusting the amount of windings around the transformer. The cables and electrodes, and wand stay relatively cool with the Transformer too.

Good Luck,
Ryan
 

Rad

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Aug 18, 2017
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jonyjoe505 said:
I recommend the maletrics arduino spotwelder, cost is 75 euros (93 dollars) just for the welder, you have to buy the probes seperate. I been using the older version since last year, the newer version is a major improvement but cost the same. He sells it off his malectrics.eu website, from germany shipping I got it in a week ...
Agree. I just bought theMaletrics spotwelder. Itis well designed and well made. I use lipo batteries to power it. So far I have just done some test welds, no big production yet.
 

ozz93666

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Feb 22, 2017
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Before anyone buys a spot welding machine I would advise looking at this 7 min video ...https://www.youtube.com/watch?v=o1NFbchHeM8

I have a similar setup using 2s 20p 18650s as power source , switching is done by a motorbike starter solenoid , results are amazingly consistent and reliable .
 

Korishan

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Simple parts and simple to assemble. Great! :D
 

TheStealth

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Oct 29, 2020
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Sorry for reviving an older thread, but after 2.5 years I think things have changed. I want to start some small battery projects and am looking for a good inexpensive spot welder. Is there anything new out there not already covered in this thread?
 

jonyjoe505

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stay away from this cheap one. I wanted to test if a cheap tab welder would work (cost 25 dollars) and the answer is no. The first couple of tabs I did were weak, so I decided to increase the power to 7, and it blew something mosfets? it was a waste of 25 dollars.
I'm still using and recommend the maletrics.


image_shoxmt.jpg
 

TheStealth

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jonyjoe505 said:
stay away from this cheap one. I wanted to test if a cheap tab welder would work (cost 25 dollars) and the answer is no. The first couple of tabs I did were weak, so I decided to increase the power to 7, and it blew something mosfets? it was a waste of 25 dollars.
I'm still using and recommend the maletrics.


image_shoxmt.jpg

I stumbled across that one and after doing some poking around summarily dismissed it. I'm leaning towards the Maletrics, but cannot decide if I want to go the car battery route or the lithium battery route. Any advantages to go with one or the other?
 

jonyjoe505

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The newer version of the maletrics does both, I think the lead acid works best for welds. On my old version of the maletrics which isn't suppose to work with a 3s lithium pack, I have tried it with 3s li-ion and a 4s lifepo4 pack. With a 3s pack I was getting weak welds, with the 4s I was getting decent welds but with a agm lead acid I got excellent welds.

I been using a 16ah oddessey which I bought on craiglist for 80 dollars and it works excellent, plenty of power. Its a small but heavy agm battery that can easily jumppstart a V8. Beautiful battery.


image_mofxoy.jpg
 

daromer

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If you get bad welds on the lithium thats because you built a to small pack. LA vs lithium does not matter as long as the battery can deliver what is needed when you push the button!...
 

jonyjoe505

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yes I agree, my 3s li-ion was a 3s6p (using sony 1500mah vct3), I was sure it could do the job but it couldn't. The 4s lithium pack was a 4s6p (using A123 cells) and performance was lackluster. To me it was just a test to see if it was possible that way I could get rid of the heavy agm.

The recommended lithium to use is the 3s lipo packs, but I don't like the idea of keeping those around just for tab welder use. They recommend a lead acid in the 40ah range, but I used with a 27ah and now this 16ah agm. No need for a giant car battery to power the tab welder.
 

daromer

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6p is far from enough... You need twice that atleast!
Lithium is alot more powerfull than agm but you should go for the high power Lithium like a standard RC battery that easily delivers the power on a fraction of a LA size and weight.

A smaller La works thats correct but keep the charger on. You stress the LA alot more being smaller. With that said the recommendation is for those who use standard type LA. They arent as powerfull unless they are larger. Its same on my car. I use 20Ah batter on my built car whilst original is 80... No problem at all but it cost 3x instead to save the weight and still can start the car
The problem is that if i run out of gas im screwed.. It wont be able to keep turning the motor that many revs before its dead :D
 

FLRobert

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Jan 18, 2022
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What do you guys think about these little set ups you can buy on amazon? seems like as long as you are not doing nickel that is too think they work fine. Any thoughts.

 
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