Simple spot welding machine

In amateur radio practice, resistance welding is not often used, but it still happens. And when such a case comes, but there is neither the desire nor the time to make a good and large machine for spot welding. Yes, even if you do it, then later it will lie idle, since its next use may not come.
For example, you need to connect several batteries in a circuit. They are connected with a thin metal strip, without soldering, since batteries are generally not recommended for soldering. For such purposes, I will show you how to assemble a simple spot welding machine with your own hands in about 30 minutes.
  • We need an AC transformer with a secondary winding voltage of 15-25 Volts. Load capacity doesn't matter.
  • Capacitors. I took 2200 uF - 4 pieces. You can have more, depending on the power you need to get.
  • Any button.
  • Wires.
  • Copper wire.
  • Diode assembly for rectification. You can also use one diode for half-wave rectification.

Diagram of a resistance spot welding machine


Simple spot welding machine

The operation of the device is very simple.When you press the button installed on the welding fork, the capacitors are charged to 30 V. After this, a potential appears on the welding fork, since the capacitors are connected in parallel to the fork. In order to weld metals, we connect them and press them with a fork. When the contacts are closed, a short circuit occurs, as a result of which sparks jump and the metals are welded together.
Simple spot welding machine

Assembling the welding machine


Simple spot welding machine

Simple spot welding machine

Solder the capacitors together.
Making a welding fork. To do this, take two pieces of thick copper wire. And solder it to the wires, insulating the soldering points with electrical tape.
The body of the plug will be an aluminum tube with a plastic plug through which the welding leads will stick out. To prevent the leads from falling through, we place them on glue.
Simple spot welding machine

Simple spot welding machine

Simple spot welding machine

We also place a plug on the glue.
Simple spot welding machine

Simple spot welding machine

Solder the wires to the button and attach the button to the plug. We wrap everything with electrical tape.
Simple spot welding machine

Simple spot welding machine

That is, four wires go to the welding plug: two for welding electrodes and two for the button.
We assemble the device, solder the plug and button.
Simple spot welding machine

Turn it on and press the charge button. The capacitors are charging.
Simple spot welding machine

We measure the voltage on the capacitors. It is approximately 30 V, which is quite acceptable.
Let's try to weld metals. In principle, it is tolerable, considering that I did not take completely new capacitors. The tape holds up pretty well.
Simple spot welding machine

Simple spot welding machine

Simple spot welding machine

Simple spot welding machine

Simple spot welding machine

Simple spot welding machine

But if you need more power, then you can modify the circuit like this.
Simple spot welding machine

The first thing that catches your eye is the larger number of capacitors, which significantly increases the power of the entire device.
Next, instead of a button - a resistor with a resistance of 10-100 Ohms. I decided that I’d stop fiddling with the button - everything charges itself in 1-2 seconds. Plus, the button does not stick. After all, the instantaneous charge current is also decent.
And the third is the choke in the fork circuit, consisting of 30-100 turns of thick wire on a ferrite core. Thanks to this choke, the instantaneous welding time will be increased, which will improve its quality, and the life of the capacitors will be extended.
Simple spot welding machine

Capacitors used in such a resistance welding machine are doomed to early failure, since such overloads are not desirable for them. But they are more than enough for several hundred welding joints.

Watch the assembly and testing video


come back
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Comments (11)
  1. Guest Alex
    #1 Guest Alex Guests 27 December 2017 15:17
    4
    Conders will die quickly.
  2. popvovka
    #2 popvovka Guests January 5, 2018 10:14
    5
    It needs to be done with low voltage, but high current.
  3. Vyacheslav
    #3 Vyacheslav Guests 5 February 2018 20:07
    0
    Soldering would be easier.
  4. Guest Vladimir
    #4 Guest Vladimir Guests 7 June 2018 14:21
    0
    What if I do the same thing, only without the coil, and connect a 12V battery from the car? Or from two batteries connected in series so that there is 24V.
  5. Soldering iron
    #5 Soldering iron Guests 1 March 2019 17:27
    6
    you can immediately see a person who is far from electrics, Any button, Diode assembly for rectification. You can also use one diode for half-wave rectification. Next, instead of a button - a resistor with a resistance of 10-100 Ohms. And the third is a choke in the plug circuit, consisting of 30-100 turns of thick wire on a ferrite core.
    Well, everything is simple here, the main thing in welding is current!!! and at 1 volt you can weld, and we weld different metals through carbon brushes.
  6. sarkazm
    #6 sarkazm Guests 8 September 2019 22:09
    6
    Hello everyone! Friends, it's crazy! What discussions might there be? Conders will die, do you need batteries? This is hilarious. But no one was confused by the clock button in the welding chain. The author spent his time to “kill” yours.. Why shouldn’t such “hemp” be used in a car’s starter circuit. No, the auto industry is adding powerful relays, and the starter itself is equipped with an additional power unit. Are they being perverted, are they increasing the price? The button will fire the first time you press it, but the “welding” process will not start! Although the author knows better..
    1. alex
      #7 alex Guests November 6, 2019 06:43
      2
      so the button is not for the welding process, but for charging capacitors
    2. Ilgiz
      #8 Ilgiz Guests 8 November 2019 15:33
      2
      Dude, what did you even look at the diagram with? Where is the button in the chain? laughing
  7. Guest Alexander
    #9 Guest Alexander Guests January 25, 2020 00:32
    1
    So according to the diagram there is a short circuit. Everything will burn on the first try.
  8. Valery
    #10 Valery Guests 21 August 2020 12:16
    1
    I bought transconders and the whole thing only worked once, as I understand it, the conders died, I threw all the costs in the trash)))))))
  9. Sergey Ivanovich
    #11 Sergey Ivanovich Guests 29 May 2022 14:35
    3
    I read the comments and am in awe. No one has a clue about this. Someone copied the primer at school. And read between the lines.