What spot welder are people using these days?


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copec

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Apr 22, 2020
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I'm ready to purchase something as I've always soldered, and wondered what the good value item is these days?

I'm sort of up for anything. I want to spot weld nickel strip, but also if I can spot weld the aluminum tabs on pouch cells, that would be a plus.

I'm looking at items on Amazon and eBay, as well as https://malectrics.eu/product/diy-arduino-battery-spot-welder-kit-v3-2-2-full-bundle-lipo-battery/ and https://www.keenlab.de/index.php/product/kweld-complete-kit/

Okay, now looking for something in the US I can grab quickly while I wait for something of higher quality to get shipped to me.
 
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floydR

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Aug 23, 2017
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From what i understand keenlab.de ships fast normally I would suggest buying from keith but he has been mia for the last month maybe longer. Last post I saw of his was jan1 on kweld north america fb page Kweld is the way to go. best battery powered spot welder out there. Doubtful about spot welding aluminum many use bolts or pop rivets. But I never tried spot welding aluminum.
Later floyd
 

Dr. Dickie

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Sep 23, 2020
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I used the maletrics, and am quite satisfied. Everyone love the Kweld, but I never could figure out how to order one in the US.
I welded 32 gauge wires, not the nickle strips, but welding is welding.
 

cak

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Mar 14, 2021
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I have one of those boxy aliexpress ones that I wouldn't recommend but needs a new home since I got a Kweld and am never looking back. You can have the alli one if you pay shipping, I am USA MN based.
 

higher_wire

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Aug 30, 2017
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kWeld is great for hobby use. 3D print an electrode holder and case and you're set. I've welded until my hand cramped and it was still going strong. We actually have a pair of them for small mobile jobs and reached out to Keenlab about US distribution after Keith went dark.

kWeld cannot do aluminum.

@Dr. Dickie where did you find a maletrics in the states?
 

Dr. Dickie

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I think I probably got it from Germany, but I could get it. I could not find anyone selling Kwelds that would even ship to the US.
 

italianuser

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Feb 25, 2020
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@copec did you get yourself the unit after all?

I'm using a Sunko 709AD, bought it on AliExpress at less than 200€ (shipping from the EU so I paid no extra tax fees). Haven't used it a lot yet, did maybe a couple of hundred spots but it's a pleasure to use with the pedal.
 

paddy72

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Nov 17, 2021
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If you're really into DIY here is a spot welder build from an old welding transformer with a new secondary winding in 120mm2 copper (4 wires in parallel, 4 turns): DIY spotwelder with timer control (german)

I added an electronic timer to select the weld time in ms (from ca. 25 ms to ca. 500 ms) or a free manual weld. It can produce ca. 2 kA for a few sec. until the fuse trips. The switching is on the primary side via SSR (solid state relais) in 2 phases, the first for pre-magnetising the core to reduce initial primary current. A 70mm2 copper cable get very hot after only 1-2 sec. of welding at the highest settings. The welding transformer has a 5-state switch at the primary side to adjust the windings.
 

Stevenmann

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Jan 20, 2022
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Cheap chinese spot welder with modifications and i built 14s with 0.2mm double stack
 

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harrisonpatm

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Jan 5, 2022
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Anyone else a fan of DIY MOT spot welders? Control board for dual pulse from ebay was less than $20, if I remember, and everything else was salvaged for free. By no means is this the nicest or best spot welder available, but it does the job if you get your settings figured out, and it's hard to beat the price point and learning experience.

IMG_20220516_163011.jpgIMG_20220516_170555.jpgIMG_20220516_171510.jpg
 

Greg Geter

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Aug 6, 2022
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From what i understand keenlab.de ships fast normally I would suggest buying from keith but he has been mia for the last month maybe longer. Last post I saw of his was jan1 on kweld north america fb page Kweld is the way to go. best battery powered spot welder out there. Doubtful about spot welding aluminum many use bolts or pop rivets. But I never tried spot welding aluminum.
Later floyd
Cannot agree more about the kweld. I built a 20kw pack for my ev with it. 1152 cells total (96s12p) and the unit never quit. Pretty sure I burned up the two server power supplies I was using to power it.

Done with my project, considering selling the kweld. I have the capacitor bank with it and other extras.

I'm a new member here. Here is my project and where I tend to hang out to discuss packs, BMS, and charging: https://openinverter.org/forum/viewtopic.php?t=1248
 

italianuser

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Feb 25, 2020
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Pretty sure I burned up the two server power supplies I was using to power it.
Just out of curiosity: I suppose that to burn the power supply it means it was under-dimensioned, right? Server power supplies do handle enough amperes but probably not the sort of spikes a spot-welder produces.

The first thing I did when I bought a second hand lab PSU was to "upgrade" it, powering heatsinks and air-flow.
 

paddy72

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Nov 17, 2021
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I also wonder how you could burn 2 server PSU's as they normally have OCP and OVP (over current and over voltage protection) and also overload protection. Maybe it was a small rahter unprotected one (don't know any) or you managed to overcome the protection. Many server PSUs can handle currents up to 60, 80 or even 200 Amps - the last might be already too much for a super capacitor, although the very big ones (2000F+) handle these currents easily. I have a few 500F supercaps that tend to get warm already at charging currents of 10+ Amps although they can deliver 40 - 50 Amps cont. and a few hundred A peak. The very big ones give you a few thousand Amps peak if using strong enough cables and connections.
 

Greg Geter

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Aug 6, 2022
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Just out of curiosity: I suppose that to burn the power supply it means it was under-dimensioned, right? Server power supplies do handle enough amperes but probably not the sort of spikes a spot-welder produces.

The first thing I did when I bought a second hand lab PSU was to "upgrade" it, powering heatsinks and air-flow.
I used two server power supplies in parallel. They still work well, but they struggle on the first two welds, then run fine after that. Odd behavior, but never let me down after some 10K welds.
 

paddy72

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Nov 17, 2021
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So you didn't really 'burn' them? What is the current capability of the server-PSU? For a solid weld you need at least 4 - 500 Amps unless you use very thin material. Of course you can weld thin alu-foil with just a few 10 amps ;-)
 

floydR

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Aug 23, 2017
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Kweld with a capacitor bank powered by 2 server power supplies would have been 1500A+? My kweld does 1000- 1300A with a single 5000mAh 3s Lipo.
Later floyd
 

Festus

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Aug 26, 2022
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Cannot agree more about the kweld. I built a 20kw pack for my ev with it. 1152 cells total (96s12p) and the unit never quit. Pretty sure I burned up the two server power supplies I was using to power it.

Done with my project, considering selling the kweld. I have the capacitor bank with it and other extras.

I'm a new member here. Here is my project and where I tend to hang out to discuss packs, BMS, and charging: https://openinverter.org/forum/viewtopic.php?t=1248
I'll be looking for a welder at some point. Are you still considering selling the kweld, and are you willing to ship to the US?
 

Greg Geter

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Aug 6, 2022
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I'll be looking for a welder at some point. Are you still considering selling the kweld, and are you willing to ship to the US?
I'm in Texas, technically the US. Happy to talk about parting it out.

I have the Kweld full assembly kit with acrylic case, kcap module with case, and ksupply. Also have extra set of copper tips. Purchased in Jan 2021 for ~$500.
 
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