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Thread: DIY Super Cap Battery Spot Welder - Real Deal or Fake Clickbait? (4K)

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    tsbrownie's Tools

    DIY Super Cap Battery Spot Welder - Real Deal or Fake Clickbait? (4K)

    There are lots of videos on the internet about making a battery spot welder using only a 500 F super capacitor and some copper electrodes. Is it real or is is clickbait?







    WARNING: Welding is dangerous and carries the risk of burns, fire, shock, electrocution, etc. Welding batteries carries additional risks of toxic chemicals and explosion. If you do not know, do NOT do it!

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    Claudio HG (09-13-2020)

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    Thanks tsbrownie! We've added your Mini Spot Welder to our Welding category,
    as well as to your builder page: tsbrownie's Homemade Tools. Your receipt:




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    tsbrownie (09-12-2020)

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    Claudio HG's Tools
    I wonder how much current is required to weld that thin seet of metal, is it 100A, 1000A ? I have a bunch of capacitor laying around that I would like to put on service for a mini spot welder one day.

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    tsbrownie's Tools
    Quote Originally Posted by Claudio HG View Post
    I wonder how much current is required to weld that thin seet of metal, is it 100A, 1000A ? I have a bunch of capacitor laying around that I would like to put on service for a mini spot welder one day.
    It has been a long time since I learned about this in shop class, but if I recall correctly there's a lot going on. Total amps are important, but amps per square area (in the welded spot) is more important to get the metals to melt in that spot. A bigger spot / tips requires more amps total (and it increases as pi * r squared). That's the basics for welding stuff like cars, tin boxes, etc. When you start welding batteries and power carrying connections there's another consideration that's very important. The total area of those "spots" would have to be at least equal to the cross sectional area of the other conductors or the spots would heat / burn.
    I tried making the spot smaller, and got a couple of welds that "took", BUT the spots were so small that in moving current they would not pass 1 amp without burning, let alone 10-20 amps. That's why in the video I said something about needing 12 welds per battery end to get an effective (power carrying) connection.
    I'm sure it can be done / is done and can produce a good spot weld, just not like the many videos on the internet with one 500 farad cap.


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