[tonetegeatinst]

Unsure, but I also wonder why a secondary pump wasn't used to get even lower pressures, like a cryopump or turbo molecular pump.

Best guess on that might be cost.

I'd assume he was trying to do everything close to the atmospheric pressure even if its an intert gas's, because its less variables. And if a leak occurs you don't have a large pressure difference to help blow the hazardous elements everywhere.

[aDyslecticCrow]

From what I can recall from watching most of his videos over the years, he doesn't have any fancier vacuum pumps, so it would indeed be a piece of new equipment he would have to buy.

He cycled the argon five times, which is probably plenty without the need for new equipment. He also melted titanium to ensure that any remaining reactive gases were destroyed even after five cycles of argon.