How do you spot weld pure nickel strips?

#21

Save yourself the time and just buy one like kweld or the boss level

Simpler and cheaper

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#22

cells arent made out of nickel

#23

No shit

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#24

The whole point of this comment is really unclear to me I thought you were presuming cells were nickel since they are easier to weld too. No need to be disrespectful my man

#25

Steel has higher electrical and thermal resistance hhan nickel.

For spot welding you need to concenhrahe enough heat in a small area until metal melts.

High resistance makes more heat. Lower thermal conductivity keeps heat in smaller spot.

I had not considered melting point though. Seems like the other 2 factors dominate?

Most cell bodies are steel.

#26

If you prefer to build your own,

Or malectrics, I think they have a kit. I canā€™t mememberā€“they might be related?

Malectrics, boss and kweld have good reputations.But some people have had their boss blow up.
Kweld is probably best but overkill :slight_smile:

Your mot welder can probably be made to work. Need more current at the tips. You can try lowering resistance (shorter thicker wires, better contacts, meatier probes), changingstransformer winding ratios, or increasing ā€œonā€ time.

#27

Yes, if I wonā€™t be able to get mine to work right Iā€™ll get my self the kWeld.

Thanks for the info man :slight_smile: The kWeld is my most favorite DIY spot welder so I might go with that one.

This is how my DIY spot welder looks like, it has 60cm of Gauge 4 cable which is pretty thick.
Do you think making it shorter will do any diffrence?

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#28

The wires look fairly short! I would try changing the probes first, to copper somehow.

I canā€™t help, but Iā€™m curious, whatā€™s your timer?

#29

First thing I did after finding out pure nickel wonā€™t weld is to purchase these probes.
Unfortunately it didnā€™t help, I hope they are good enough. Maybe I need something thicker?

My timer is a foot switch pedal, nothing too fancy :wink:

#30

You just manually time it? Whoa. :slight_smile:

Have you tried soldering those copper probes directly into the 4awg cable ends? No brass?

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#31

Yes, itā€™s done manually :muscle:

I used gas torch and tin to make it to reach melting point, then attached the probes directly on the melted tin and this is how itā€™s connected to the gauge. The brass is just to cover it so Iā€™ll be able to
hold the cables.

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#32

So, Iā€™ve watched a number of youtubers go through the same progression. MOT -> timer circuit with relay -> SSR -> some arduino thing. Maybe you can skip the middle steps. :slight_smile: Timing it with a foot pedal seems like itā€™ll lead to vent with flame.

I just remember this from the first post. This is not good! Really bad actually. Everything should be mechanically secured, or allowed to flex, so as to not put movement on the weld joints.

#33

Malectrics welder with a 750CCA car battery has been reliable and quick. 3d printed case with fan and fuse is nice. Relatively compact package. Works with car or lipo battery. Very glad I went with that over a Sunkko model.

#34

Second thats I had a yumcha spot welder from ali it was useless. When it wasnt tripping the breakers it would struggle with .15 nickel.
Kweld will blow through .2 and copper strips. its a spot welding god. Easy to fix as well.

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#35

Canā€™t believe you killed one. :bowing_man:

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#36

Glad Iā€™m not the only one who was using that method, haha.

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#37

I have that boss level welder and Iā€™ve welded pure nickel to batteries with success (canā€™t rip the welds). My power supply is 3 parallel 12V golf cart batteries and 12 inches of 8 awg wire to the input. With a single 12V lipo the welds werenā€™t very good, so it seems supply matters a lot.

#38

need atleast a 65C rating on a 3S lipo to be decently effective I think.