Musk also claimed that "there have not been new car [brands] that have been successful for 100 years, apart from Tesla."
Some automotive brands that were founded in the last 100 years:
Chrysler (1924)
Volvo (1927)
BMW (1928)
Datsun/Nissan (1931/1933)
Fiat (1932)
Toyota (1936)
Volkswagen (1937)
Jeep (1943)
Land Rover (1948)
Honda (1963)
Those are polite ways of saying stainless steel is hard to work with, and flat expanses of bodywork are unforgiving when it comes to gaps, fit, and finish.
Why would stainless steel be any harder to work with than normal steel?
Stainless steel is alloyed with chromium nickel and other stuff. It's harder to cut, shape and weld. The wear on tools is also higher and it work hardens faster (it loses its plasticity faster as it's deformed).
That's not true at all. It's because when you touch it, your mom yells "TheFartographer!!! I told you you're not allowed to use the nice silverware! Get back in your hole!" Sometimes you also get sprayed with the naughty hose.
It's unpainted. On a painted vehicle, a dent or a scratch is a sanding, cleaning and a painting away. Paint can fill scratches and voids. If the entire surface is bare metal, you can't bodyfill it if it gets a dent and you can't weld metal into it or onto it to fill a void without marring the finish.
I don't get why they can't just make the thing out of aluminium and paint it a metallic silver. It'll look just as nice if not better, be cheaper to make, weigh far less, and consequently have a longer range and/or require a smaller battery.
After it's been sold, or even on the lot surrounded by other vehicles coming and going all day. Even if it's driven down the road once, the front bumper will be pitted with rock marks.
I highly, highly doubt it will be made entirely of ss. The dissimilar metals problem will be real. But it'll be branded 'electrolysis' which sounds more high tech than 'rust'
Stainless work hardens quickly. So if there's a dent, it's now "harder" than anything around it. Most steel can be moved around quite a bit before it starts to harden in any useful fashion. It's also, generally, harder. So it wears out tools and tooling faster.
I read a comment recently that the flat shape of the panels are going to have a tendency to want to buckle inward or outward as they flex/torque. Similar to how metal sheets behave when used to make “thunder” sound effects on old radio shows. They didn’t put any curve or arc into the panel design to prevent this from happening. Wish I could find the link to share here.