On Friday, January 31, 2014 5:50:22 AM UTC-8, wrote:

I'd like to make some little radiation shields for use at 77K (liquid nitrogen)

So cylindrical type cups.. maybe 2" diameter and 3-4" long. I've only heard about spinning aluminum, but can you also spin other metals something like TeCu (tellurium copper)

Yes, of course you can spin other metals; for a heatshield, though, Al is the right stuff.

Does the spinning work harden the metal?

Yes; that's one good reason to do it. Gongs and cymbals for instance, are almost always spun.

Can it be annealed afterword?

Yes, or between operations in multistep spinning operations.

How thin a wall/ bottom can you make?

Only limit is if the metal tears (and polished tools and/or heavy greases are recommended
to minimize this). It's recommended to spin alternately from center out and from rim in,
to get a uniform thickness result.

If you care for a less dynamic approach, you can also consider cold-drawing of
aluminum; machine an internal die and press a metal sheet against a block of rubber
(urethane? neoprene? silicone?). It'll take several steps and annealing between draws.