If you're that worried about PC-based immolation a liquid-cooled one might be better? I'm fairly sure PCs come well down the statistical table of domestic fire starters.
Not welded by NASA; NASA shuffle paper, train astronauts and write cheques; Grumman, Martin Marietta, Lockheed, Aerojet, Morton Thiokol, Pratt & Whitney, Rocketdyne, North American Aviation, Rockwell etc, did/do the fabricating bit.
RAF gyros have a rep for killing their occupants; they need horizontal stabilisers which the designer and manufacturer did not deign to include. Once modified they seem ok safety wise.
It would originally have had something like this to fit disposable cylinders, like this...
... or this.
Once you've decided you like welding moving to a big cylinder will make life much cheaper, as disposable cylinders only last for perhaps 10 minutes welding. Machinemart sell everything...
Welding near significant quantities of any volatile solvent is a bad idea regardless of whether it has chlorine compounds in it; if you're degreasing let the stuff evaporate for a reasonable time first.
The probable future state of the british army; one admittedly well equipped bloke talking to himself on a radio to avoid being overwhelmed by a sense of impending doom and futility.
Pretty crap online listing; they might as well not have bothered. On the other hand having it as an old fashioned auction were you have to turn up does increase the potential for bargain buys if there are oddball lots mixed in. I considered going but the weather put the kybosh on that.
What's your risk perception? Thorium is present in more or less everything, granite, soil and coal being the common ones; coal-fired power stations emit thorium out of the lum(fly ash) and in the bottom ash. A nuisance dust mask will give you all the protection you need, or fit your offhand...