Strong hand-held spot welder?

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rg12
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Strong hand-held spot welder?

Post by rg12 » Nov 18, 2017 4:21 am

Hey Guys,

I have a small spot welding machine that is strong enough for welding 0.15 pure nickel.

The thing is that I want to spot weld with the hand-held attachment using the pedal in order to get "deeper" into the pack but since there are losses in the wires that go into the hand-held add-on then it isn't capable of spot welding 0.15 pure nickel.
* The wires are copper, super thick and pretty short so I don't think I can upgrade the add-on

Do you know of a strong spot welder that can do what I need? I prefer one that doesn't cost thousands of dollars (mine works perfect without the hand-held add-on and costs less than $200)

EDIT:
This is the machine I have now:
https://www.aliexpress.com/item/1-9kw-S ... KKWkYT&s=p

It is rated at 1.9Kw

This is the only handheld machine I found which looks stronger but is rated at 10KVA (whatever that means):
https://www.aliexpress.com/item/LCD-dis ... eLevelAB=0
Mongoose EC-D 2007 (19" motocross wheels), 21s 10Ah LiPo, Greentime 72V 80A Controller, 12kg Hub Motor

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Re: Strong hand-held spot welder?

Post by jonyjoe303 » Nov 18, 2017 1:38 pm

I bought a DIY arduino spot welder version 2 (malectrics.com) , I payed about 100 for it, I use it to weld 015 pure nickle. The probes are connected to the unit with 6 gauge pure copper welding cables (about 2 feet). It welds 015 quite easily and I usually have it set at 15 percent power level. There are several of these welders reviewed here in the forum and also on youtube, but all run on a 12 volt car battery (some on rc battery pack) no house current. The only problem they are not ready to use, you have to connect your own cables/probes etc. Originally I used 8 gauge speaker wire and was unimpressed with their performance, I had to use 80 percent power level to get it to weld properly and the cables got very hot to hold. 6 gauge pure copper was a joy to use.
Looking at the picture of what you got, the probe wires don't look thick enough and it got see-thru plastic it doesnt look like they use pure copper for the wires. Pure copper would be heavy. I hardwired the probe to my spotwelder and the spotwelder is connected to the battery with xt90 connectors (can handle 90 amps). The connectors on your unit look like rca plugs, they will pass current but maybe not enough like xt90 connectors. What you are looking for is available and not that expensive but require a car battery to run off it. Anything using house current will be many times more expensive.

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Re: Strong hand-held spot welder?

Post by rg12 » Nov 18, 2017 4:21 pm

These things don't seem like they can last long (I build many huge packs)

The seller just replied and said that it will work with 0.15 pure copper but I need to trust a Chinese seller promising me that on AliExpress......
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Re: Strong hand-held spot welder?

Post by brumbrum » Nov 19, 2017 5:58 am

Why dont you just buy one of these... https://endless-sphere.com/forums/viewt ... 31&t=68865

Fully assembled just bolt to an old car battery.

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Re: Strong hand-held spot welder?

Post by brumbrum » Nov 19, 2017 6:03 am

rg12 wrote:
Nov 18, 2017 4:21 pm
These things don't seem like they can last long (I build many huge packs)

The seller just replied and said that it will work with 0.15 pure copper but I need to trust a Chinese seller promising me that on AliExpress......
I personally would not trust that statement. Copper is much more difficult to weld than nickel, especially over 0.1mm

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Re: Strong hand-held spot welder?

Post by rg12 » Nov 19, 2017 9:47 am

brumbrum wrote:
Nov 19, 2017 6:03 am
rg12 wrote:
Nov 18, 2017 4:21 pm
These things don't seem like they can last long (I build many huge packs)

The seller just replied and said that it will work with 0.15 pure copper but I need to trust a Chinese seller promising me that on AliExpress......
Oh Sorry, I meant to say pure nickel...
Another seller of the same machine said that for 0.15 pure nickel I should set the machine to 45% power so it sounds promissing.

I personally would not trust that statement. Copper is much more difficult to weld than nickel, especially over 0.1mm

brumbrum wrote:
Nov 19, 2017 5:58 am
Why dont you just buy one of these... https://endless-sphere.com/forums/viewt ... 31&t=68865

Fully assembled just bolt to an old car battery.
That isn't cheap at all and I can't trust this little thing to work all day long without burning it's fets at some point.
Mongoose EC-D 2007 (19" motocross wheels), 21s 10Ah LiPo, Greentime 72V 80A Controller, 12kg Hub Motor

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Re: Strong hand-held spot welder?

Post by brumbrum » Nov 19, 2017 10:46 am

Why cant you just make your own probes with 6awg silcone wire and some crimped and screwed on pure copper electrode ends?

Btw, the jp spot welder seller will supply you with just the copper electrodes or cables if you wanted. Though silicone covered cables would be more suitable if do a lot of welding as they will last longer and get less streessed when moving around as they are softer

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Re: Strong hand-held spot welder?

Post by rg12 » Nov 19, 2017 11:39 am

For that I will need to hack my spot welder since the handheld sockets are just sockets and not big copper plates with a hole for a screw.

I just ordered the handheld spot welder, it seems stronger and is only $170 so I will give it a shot.
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Re: Strong hand-held spot welder?

Post by brumbrum » Nov 19, 2017 3:41 pm

My guess, and its only a guess, it will be eaxctly the same as the welder you have already, just with different shell.
It would be interesting to see how many parts differ inside if you remove the covers and compare.
I hope it works out for you, best of luck.

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Re: Strong hand-held spot welder?

Post by progrock » Nov 20, 2017 12:10 am

OK, I would bet my life that there's no way that thing can do 0.15 copper legitimately. Without a bank of super capacitors, I can't imagine anyone's home AC power being able to provide the pulse of energy needed to do legit copper welds... nickel is hard enough for most homes, and blows many fuses (which is why these Chinese welders were never even an option for me... if my apartments power lines we're ancient, I may have given them a try, but def not for copper). As for handheld spot welders, I've been growing very knowledgeable, and have a few different ones myself.

The first recommendation you were giving is a very solid unit, at a bargain of a price.... the DIY arduino based spot welder: https://www.instructables.com/id/DIY-Ar ... ot-Welder/

You literally cannot beat the price of that, the creator sells the PCBs and machined aluminum nearly at cost (I can't stress how good of a price it is, especially considering 1 of the PCB boards is 2oz copper). It also uses 8 x IRFB7430's.... which are really nice MOSFETs (one of the best for this type of device), and lots of other similar welders use 6, often with weaker fets. This thing is rock solid.... and if you are doing A LOT of welds, it's likely worth going with a car battery instead of a LIPO (the newer, very high discharge Lipos definitely do the trick, but they only last so long). You can also get the pre-built version for a VERY reasonable price (especially considering how much an engineer's time is worth... and how little above the cost of parts it's being sold for). It's also very easy to build yourself.. surprisingly easy. It's got a great design for use with a car battery... so really a solid choice for your needs.

Another welder I own is the "BOSS" spot welder. Another arduino based design, though it uses only 6 fets, the IRF4110's, which are a little weaker than the IRFB7430's, but still very good... a lot of people have used this one quite a bit with good results. I honestly think the above one is a slightly more solid unit at an incredible price.... but this is also a very solid unit... and also at a very cheap price considering what goes into it. It can also double as a solid portable soldering iron with a knockoff hakko handle and T12 tips (better than most soldering irons people have at home). https://m.blog.naver.com/aulakiria/220992039512

The most advanced welder I know of (in this category, I'm sure there are some crazy industrial welders if you spend thousands), that I think has the most potential, is the kWeld. Sadly he just sold out this batch's pre-orders... so might be a little while before you could get your hands on one. It has a unique design concept (with regards to the controlling circuit)... instead of setting pulse times, etc... you simply set the joules per a weld. This theoretically (and seems like the test back it up) makes welds more consistent. It's definitely the most straight forward user interface (IMO).... just 1 value to set. Also, this welder has some pretty serious MOSFETs on it (a decent step up from both the IRFB7430's and IRF4110's). I pre-ordered one, can't wait to finally test it. https://endless-sphere.com/forums/viewt ... 14&t=89039

As far as welding copper goes... while some people have managed to succeed (I've seen it done with the BOSS welder), I think if you really wanted to do this consistently, the best option is to build a bank of super capacitors. BTW, a bank of super capacitors is also likely the best option for powering any of these devices if you want it to last for a long time. Unlike batteries (especially batteries being abused), super capacitors can have a lifetime of 1,000,000 charge cycles, even more (as long as they are used correctly.... overcharging, or worse, connecting backwards are both cases for disaster). But super capacitors used correctly, have the potential to last longer than any of our lives will. But one thing to note is... even more so than the other options... these can 100% be deadly if you are not careful. Of course every option is using pretty high amps, and has the potential to be very dangerous, but a bank of super capacitors has soo much potential, making a mistake is very life threatening (though if you know what you are doing, and are careful, they are relatively safe... generally the only danger is if you make a mistake)... there are plenty of videos of people destroying things with 1 super capacitor... let alone a bank of them. Sadly they are not exactly cheap... especially the ones with insanely low ESRs (in the 0.1-2 mOhm range... usaully in the 500-3000F range.... tho in this case, the ESR is actually more important than the Farads, higher F will give lots more welds before needing a charge, though I'm pretty sure all viable super capacitors are going to give you a hell of a lot... but the low ESR is what's important when it comes to supplying enough power in a short amount of time, especially when it comes to copper). I'm planning on building one of these soon, might even design my own protection board (which I'll release to the public if I succeed)... I think I finally found some that have unbelievably low ESRs, and cost a little less than the other's I've found (usually the really low ESR caps cost min $50, easily $60+ each... and probably need at least 3 to get the voltage high enough). These are the ones I just found, https://www.skeletontech.com/ultracapacitor-webstore .... sadly need to buy a box at a time (either 20 or 10 caps)... but at those specs, and that price... I think I'm gonna bite the bullet and make this happen finally.

I will be making a comparison of the 3 welders I've mentioned as soon as I have all in my hands. But my current hypothesis is that the kWeld has the most potential, while the first one I listed is the best band for your buck, and still very capable... but all 3 should be able to get the job they were designed for done. But the real goal is to get a setup that'll handle 0.1 copper without a problem (0.15 would even be better, but one step at a time). Been researching welding copper specifically, learning some potential ways to achieve it... also just certain techniques that help with spot welding any metal to batteries. One of the best things I've learned so far is to have a slot in the nickel or copper between your two weld points. This makes t so that path of least resistance for the electricity to follow is through the nickel/copper into the metal top/bottom of the battery, and back out the other side of the nickel/copper (exactly what you want)... without the slot the path of least resistance is gonna be from one of the welders tips through the nickel/copper to the other tip... instead of through the battery.

BTW, there are also other ways to utilize copper without welding it... what I plan to try on my next pack is to rty a technique very similar to what they are doing here (screw to the bottom photos to see the complete design): https://www.aliexpress.com/store/produc ... 57299.html .... basically build battery holders with knurled insert nuts at the top/bottom between the batteries. Spot weld a layer of nickel to the groups of parallel batteries, then screw down a layer of copper on top to allow for a lot more amps to flow through the whole system. This seems like a very practical technique, and doesn't require anything more than your standard nickel spot welder. They sell different size battery holders, the pure nickel (0.2mm thick) and the copper 'H' by the meter (0.3mm thick)... all for a very reasonable price. AND I can vouch for the company, anything they sell that claims to be pure nickel IS (and good quality at that)... but they do also have nickel plated steel, though it is very clearly labeled (and for that setup specifically, it's pure nickel and pure copper, no steel). The issue for me is, I've been using 20700 batteries, not 18650... so mine wouldn't fit, so I plan on 3D printing my own holders... and imitating there design pretty closely, with my own tweaks.

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Re: Strong hand-held spot welder?

Post by rg12 » Nov 21, 2017 5:47 am

Thanks alot man for all the info :)

How can I buy the first welder that you said that is the best bang for your buck?
Can I buy it complete with cables, electrodes and all?
About a car battery, is it better than a high discharge lipo?
How long does a 5ah 4s lipo last until it needs to be recharged?
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Re: Strong hand-held spot welder?

Post by parasole » Nov 21, 2017 10:33 pm

progrock wrote:
Nov 20, 2017 12:10 am
OK, I would bet my life that there's no way that thing can do 0.15 copper legitimately. Without a bank of super capacitors, I can't imagine anyone's home AC power being able to provide the pulse of energy needed to do legit copper welds... nickel is hard enough for most homes, and blows many fuses (which is why these Chinese welders were never even an option for me... if my apartments power lines we're ancient, I may have given them a try, but def not for copper). As for handheld spot welders, I've been growing very knowledgeable, and have a few different ones myself.
Nickel is welded wiht fairly low power transformer, example is modified microvawe oven transformer which typicaly come in range of 600-700 watts... then if not enough you may use two of them and still you will not blow up your appartment AC line... Cheap Chinese welders basically are the same, they use the transformer controlled on AC side to be enabled for a number of mains pulses...
Cooper definetelly will require much higher energy level sicne its conductivity (both thermal and electrical) is much higher...

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Re: Strong hand-held spot welder?

Post by jonyjoe303 » Nov 26, 2017 1:27 pm

How can I buy the first welder that you said that is the best bang for your buck?
Can I buy it complete with cables, electrodes and all?
About a car battery, is it better than a high discharge lipo?
How long does a 5ah 4s lipo last until it needs to be recharged?

You buy at the malectrics.com website, he is based out of germany, I recieved my unit to california a week after I ordered it.
He has the newest version 3 which has many improvements but at about the same price. He also sells the electrodes but they are not 6 gauge. I use mine with a 28ah battery but I don't see why you couldnt use it with a 12 volt jump pack (18ah). You should be able to do several battery packs before you have to charge 5ah lipo pack. My 28ah battery only required about 2 amps to be back to full charge after doing one battery pack.
As far as how long it will last? I so far built 2x 80 cell battery packs, the unit itself never gets hot but the cable do get warm. Myself I think it will last a long time. The builder of the unit is always improving the design to make it last longer and handle higher amps.
For the price I paid I definitely got good bang for the buck. I'm using these on the the 32650 large 5.5 ah lifepo4 cells, these cells just wouldn't solder at all like the 18650's, this tab welder did quick work on those cells.
Just remember if your cables start to get hot, replace them with 6 gauge copper welding cables, those will pass all the current to your probes instead of losing it in heat. The heavy copper cables made a big difference in my situation. When dealing with high amps, pure copper, and solid connections equal excellent results.

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