What hacker doesn’t want a plasma cutter? Even if you aren’t MacGyver, you can probably build this one in a few minutes using things you have on hand. The catch? You probably can’t cut anything more than tin foil with it, and it is probably more a carbon-air arc gouger (which uses plasma) than a true plasma cutter. Still, as [Little Shop of Physics] shows on the video, it does a fine job of slicing right through foil.
If you are like us, you are back now after getting four 9V batteries, some tin foil, a pencil lead, and some clip leads and trying it. If you have more self-restraint than we do, you might want to think about what you are going to put the tin foil over. In the video, they used a laundry basket and a rubber band, but anything that keeps the foil suspended would do the trick.
Although it isn’t really a practical plasma cutter, we were thinking about strapping something like this to a 3D printer and cutting foil stencils. The jagged edges on the video are, hopefully, more from being operated by hand and less from the jagged mini-lightning bolt vaporizing the foil.
The video repeatedly talks about lead, but a pencil lead is confusingly not made of lead. It is actually graphite (a form of carbon) which makes it a good (and inexpensive) electrode for this application, even though it is mixed with a clay binder.
If you want something more practical, prepare to spend at least a few hundred dollars or more. You’ll need a source of gas (or maybe a few gasses), a high voltage supply in the MHz range, and a hefty constant current DC power supply. You might also want to throw in LinuxCNC.