All I know is I learned you shouldn't discharge a capacitor by shorting it like he did, it usually works but it can pop them. You want a really hefty resistor to make it discharge slowly over a couple minutes instead of all at once.

Those look like the cheap welding gloves that I have.

The plank is probably good to 100KV or so, he doesn't need a glove at all for what he is doing. Funny thing is, the 120V death stick he made to power the thing is a lot more dangerous than the Jacobs ladder. Just a twist of the power cable and you have a short at the end of the line. Or you grab it and just the same.

I never use gloves for research work because a) I don't work hot circuits and b) they provide a false sense of protection. It's too easy to puncture a glove with a sharp wire. That said, you can work 60 cycle power up to 1 KV or thereabouts with bare hands if they are dry. Washing them with acetone is an old trick to give you a short window of "handling HV superpower".

Counterpoint: in order of descent into pussyness.

1) Make it.
2) Scavenge it.
3) Buy it.

I deeply regret not scavenging more MOTs when I had the chance. Not for the measly few KV you get but for the transformer core! Cut off the HV side of the turns and rewind for whatever voltage you need, from one turn and up. If you need 50-100 amps for something it's an easy and cheap solution.

Good video.

When people feel ashamed that they're buying something they use words like 'snag'