The parts from ProMetal just arrived. These parts feel heavy, dense, and strong. You really have to hold these in your hands to believe it. They hold water without leaking. Cost ~$30 each.
There is some texture, but overall these parts are highly conformal to the design.
This is very exciting. The first prototype core is within reach.
Next I will grind the touching surfaces of the lids and try to laser weld them together.
On the down side this material is magnetic:
I wonder if ProMetal can adjust the composition of the alloy. Stainless steel can be either magnetic or non magnetic depending on the alloy:
There are different types of stainless steels: when nickel is added, for instance, the austenite structure of iron is stabilized. This crystal structure makes such steels non-magnetic and less brittle at low temperatures.