If you liked the Metal Melter you saw in a previous project, here's how you can make your own!
Step 1: Find an Old Microwave
You can find them in various places, like on free classified adds, or in your neighbors garbage can, like where I found this one.
Step 2: Harvest the Transformer
CAUTION: Make sure you're familiar with the dangers of opening a microwave, because there are components inside that may still carry a charge and could hurt, or even kill you. Even if the microwave isn't plugged in.
The transformer core is only held together by 2 very thin welds, as seen on the side of this one.
A hacksaw, or angle grinder can be used to cut the weld, then a hammer and chisel used to break it open, giving you access to the primary and secondary coils.
Be very careful taking the primary coil out because you'll need it again. Make sure not to bend, break or scratch it in any way.
NOTE: The secondary coil is harder to get out, and may be damaged by the time you do, but that's ok because we don't need it for this project. However, if you can salvage it intact, it may be a source of thin gauge enameled copper wire for future projects.
Step 3: Re-wind the Coils
The next step is to carefully replace the primary coil, an ensure it's snug at the bottom of the core. Then add a 5' length of 2 AWG insulated copper cable. This thicker cable will extend the amount of time a massive electrical current can flow before the cable overheats.
The secondary cable is only wrapped 1-3/4 times around the center.
Step 4: Glue It Back Together
Then clamp it together to let the glue set. I used my bench vise as a clamp and it worked perfectly!
When the glue is dry, your Metal Melter should look similar to this. None of the wires are actually touching each other, but what it can do is very impressive.
Step 5: Melt Some Metal
That's enough current to melt iron nails and steel bolts on contact!
Step 6: Spot Welder
You can see how I made this in a different project.