How to Melt Metal with a Modified Microwave Oven Transformer

In a previous project, I showed how to build an electrical Jacob's ladder using an old microwave oven transformer (MOT). In this project, I modified the secondary coil on the MOT, which converts it from a high voltage/low current device into a low voltage/high current metal melter!

You can see the simple modification in the pictures below. I've saved the primary coil and replaced the secondary with 1.5 turns of 2 AWG stranded copper wire.

The first MOT in the video produces just over 500 amps, and the second one is capable of nearly 800 amps. Both are enough to turn this steel screw into a glowing stream of molten metal.

Any metal that can conduct low voltage electricity (about 2-3 volts) acts as a resistor between the electrode wires, and heats up due to the extreme electrical friction.

In the pictures below, 2 small neodymium magnets went incandescent before liquifying into a puddle of molten metal.

The tines of a fork rolled over like butter.

And by attaching some nails to the electrodes, I had a make-shift desoldering iron that melted hi-temp solder in a fraction of a second. Amazing, since my real desoldering iron wouldn't get hot enough to melt it at all!

Haven't see the video yet? You can still see it here!

If you like this project perhaps you'll like some of my others. Check them out at

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