Yes that plasma torch was incredible. Just pop a hole in half inch steel plate like it's wet cardboard.
I literally don't know how dangerous it may or may not be, I certainly would not be confident (or competent!) in trying anything like that myself but I'm watching the guys channel now and I have to say, he's pretty damned good! Brave. Balls of steel, but pretty damned good nonetheless.
I certainly wouldn't be attempting that on a petrol tank!
Diesel though isn't very flammable in comparison, probably safer to weld up a tank filled with it than with empty. Not that personally I'd want to be doing it.
Diesel isn’t that easy to set alight.
Providing it has somewhere to vent to so it isn’t contained it won’t explode, mostly just smokes and occasionally simmers. A bit like catching some underseal alight when welding.
The guy is obviously prepared for it as he has a blower on hand to snuff it out and filled it with water to start with until he had got it opened up.
I scrapped out a metal gas tank with my plasma cutter.
I'm not a risk taker by any means.
I simply filled it with water, hose in all the time, water pouring out the top hole (the large one for the sending unit)
Snap the trigger once to get the air flowing, then approach and start cutting, consumables don't get wet that way.
I had probably 2' of cut line with water pouring out and the hose kept up with it.
By that point, the tank was wide open, and not a hazard.