[Gustomaximus]

Ive watched a few YT videos where Musk does a walkabout of spacex facilities. He seems to have an impressive knowledge of the engineering detail at so many levels. Given welding must be critical for strength and weight I'd be surprised if he didn't have reasonable knowledge from a technical point of view.

I think the channel was 'Everyday Astronaut'.

I'm not an expert so perhaps it's a case of I'm easily impressed.