Spot Welder (800 Amp)

This is a spot welder I made from a transformer from a microwave oven. It was made by removing the secondary from the transformer and replacing it with two 2 AWG (stranded) wires coiled in parallel. I didn't have access to thicker wire so I used two 2 AWG wires in parallel. It would have been better to use one length of thicker wire. The open circuit voltage is 2V and the operating current is 800 Amps. It is not very powerful but I like how it turned out. It is actually very usable for very light work. The bird cage guard project in the video is really is pushing the limits of this little machine. My welder was made heavily based on the welder that Grant Thompson ("The King of Random" on YouTube) made. I linked his video at the bottom of this post.
Attachment 20455

Attachment 20456

Attachment 20457

I made a little video that shows the first couple of projects that I mad using my welder.
https://youtu.be/94lQpbIU4qs
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This is the spot welder design that mine was modeled after. (My bottom arm is fixed.)
Grant Thompson's ("The King of Random") Spot Welder:
https://www.youtube.com/watch?v=vrlvqib94xQ&t=386s

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<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-spot-welder-22"> <img src="/uploads/206911/homemade-spot-welder-22.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-spot-welder-22">Spot Welder</a> <span> by <a href="http://www.homemadetools.net/builder/scorch">scorch</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/spot-welder'>spot welder</a> </div> </div> </div> </div>
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Quote:

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Originally Posted by scorch

This is a spot welder I made from a transformer from a microwave oven. It was made by removing the secondary from the transformer and replacing it with two 2 AWG (stranded) wires coiled in parallel. I didn't have access to thicker wire so I used two 2 AWG wires in parallel. It would have been better to use one length of thicker wire. The open circuit voltage is 2V and the operating current is 800 Amps. It is not very powerful but I like how it turned out. It is actually very usable for very light work. The bird cage guard project in the video is really is pushing the limits of this little machine. My welder was made heavily based on the welder that Grant Thompson ("The King of Random" on YouTube) made. I linked his video at the bottom of this post.
Attachment 20455

Attachment 20456

Attachment 20457

I made a little video that shows the first couple of projects that I mad using my welder.
https://youtu.be/94lQpbIU4qs
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
This is the spot welder design that mine was modeled after. (My bottom arm is fixed.)
Grant Thompson's ("The King of Random") Spot Welder:
https://www.youtube.com/watch?v=vrlvqib94xQ&t=386s

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can you tell me what you used for the contact points? I want to make a welder for batteries for cordless drills and want to fix batteries by welding them with tabs. thanks

I just used short pieces of solid 4 gauge wire. I filed them to a point.

For welding batteries you need to have the two points facing the same direction so you don't put the welding current through the battery. (You probably already knew that. I wrote it just in case you didn't because it is important.)