Normally I'd never trust YouTube comments, but a channel where a wealthy scientist does all the weird experiments they've always wanted to do attracts a lot of other scientists. Their concerns make sense, too - the equipment he bought isn't rated for the use he's putting it to, let alone his future plans to make liquid helium.

And pressure vessels are one of those things where you want to be absolutely certain it's safe. You don't fuck around with Delta P - failure of a pressurized (or depressurized in this case) vessel is the kind of thing that registers on local seismographs.