Author Options:

Can a ARC WELDER be converted to a SPOT WELDER? Answered

I have this ARC welder which puts out 50 AMPS, flip the switch gives you 80 AMPS. I would like to spot weld thin metals for a project i am working on, and by all accounts on what iI have seen on the INSTRUCTABLES all I would need is the copper tips attached to the clamp device



This one gets 2.5v from every 6 windings, so it should be easy to have a go at 2-6 volts range for spot welding... I dont know how many ampers it can do. there is an amps adjuster in the middle tube. The secondary windings use 4mm copper. that is why it is called yumyum transformer :)

yumyum transformer.jpg

Thanks for the topic. I have found a 25 kilo 1970's arc welder that was pretty rusty so it's a good idea to put it to new service with lower voltage than arc welding. I measured 28v on it on the first run, with 7*6 turns of the secondary. (14 turns 3 deep devided on two coils)... it was 14.8 on a single coil. There is a coil of 6 turns only also at another stage, which i have measured at 2.5V. I have seen a 2.4v welder on YT melting .75mm steel sheets together. I hope i can do some welding with it soon, we will see.

One turn over the secondary coil with 2" x 1/8" copper bar is sufficient to spot welding. The current may be controlled with a compatible triac dimmer. 3/4" aluminum rods and 1/2" copper rod tips are good solutions to complete the spot welder.

Phil B

9 years ago

I have a welding book for farmers and ranchers by Forney. It discusses using a carbon rod to spot weld thin materials with an AC stick welder. I tried it once, but do not believe I had the materials clamped together well enough. While it may be possible, a commercial spot welder automatically times the duration of the arc. You would be on your own if using a carbon rod in a stinger. Still, with practice, it might be possible.


9 years ago

Spot welder uses 10x lower voltage and 10x higher current. so you need to rewind transformer. if you try to use it as is there will be not enough current, and it may evaporate thin metal. if you decide to make your own spot welder big problem is extremely thick cables and tips. you will need lots of copper.

Stitch Welder is what you need if your unit is AC output.
I have used one on car panels worked good. Its realy just a huge diode in a nice handle

I believe your welder would have too much power for the thin metals. I guess the only way to find out is to try it out though. If it doesn't work you could always get an old microwave and make that into one. The spot welder I made from a microwave transformer works very well. It is similar to this.