You can spot weld, tack weld and burn holes in metal with this welding gun you can make yourself.
AFTER YOU BUILD this arc-spot welder, you'll find that you can spot weld sheet metal without a back up, also tack weld, and burn holes in sheet metal faster than you can drill them.
And, as you use the gun, you'll discover many more jobs it will do faster, easier and better.
The "secret" of its operation is the copper nozzle that acts as a shield and heat sink for the arc. The tremendous heat is concentrated on a small area for a short length of time, and with the springs tending to push the gun back at the same time the rod is burning off, a spot, plug, or tack can be made in less than a second.
You have a lot of leeway when rounding up the materials; in fact, your scrap box probably contains some parts that can be used. Just as an example, the handle on this welder was originally part of a toy machine gun.