# Spot Welder - Ebay



## dcb (Dec 5, 2009)

I've seen quite a few designs for them (i.e. modified microwave transformers),

the two things that jump out at me are 
1. a foot switch, so you can apply the appropriate pressure before you apply current. (some go as far as to have a means of consistent pressure and time @ current). Maybe that has it built in when you lift? Also the needles need even pressure, so if the arms move independently then that is a good thing.

2. the electrode material, copper will tend to stick, I don't recall the recommended material though (inconel?)

3. nickel is easier to spot weld than copper because it has more resistance.

4. It may be hard to juggle everything in the air like that. Most designs I've seen let you lay the work down, put the battery bar in place, then apply the electrodes.

"E. Welding switch: it is in the head of machine, when the solder needle down to the weldment
and the switch closed, the welder is going to work, this switch is easy to be broken"

LOL, well it would be good to know if it works right, regardless.

but a modified microwave transformer and a footswitch and a couple of hand-held electrodes is probably more than adequate for 60 cells.


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## Hollie Maea (Dec 9, 2009)

You'll definitely want to use Nickel (like Nickel 200 or 201). Spot welding Copper doesn't work very well.


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## Karter2 (Nov 17, 2011)

Many users of those spot welders have poor experience, bad results, and even complete unit failures.
They are not true "dual pulse" as advertised, which is essential for quality welds.
Look here... http://www.endless-sphere.com/forums/viewtopic.php?f=31&t=68865
...for a much better solution.


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## riba2233 (Apr 29, 2015)

Thanks for the recommendation!


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## Karter2 (Nov 17, 2011)

No problem...
Good products always deserve recognition


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## riba2233 (Apr 29, 2015)

Thanks, well they got recognized, but I wish I could make more of them, there are a lot of people who want them, but I can't make them fast enough.


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## eldis (Sep 3, 2013)

I was wondering, why is nickel used almost exclusively as a material for strips? Would there be some issue with using for example thin sheet of stainless steel? I presume that the welding current would go up. I've hand-soldered a lot of 18650 cells for e-bikes (using nickel strips), and never encountered a failure resulting from excessive heat, so the welding of harder material should not be too much of an issue either..

Any other problem you could think of? Am I missing something?


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## kennybobby (Aug 10, 2012)

Stainless steel strips will work fine, nickel is a component in most stainless steels.


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## riba2233 (Apr 29, 2015)

Nickel plated steel (hilium) is second most often used material for welding, but it has greater resistance. Copper can also be used, but it's harder to weld and sometimes unpredictable. Nickel is best compromise between those two. I've also tried Al, but without any good results.


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