Hm, about manufacturing the onion with rapid prototyping, I don’t think that’s feasible, because that would repeat the process 2000 times for 1000 layers of conducting foil. It already takes a few hours for each process, even with speeding it up it’s unrealistic. Possibly just build the onion’s skeletal features, it’s cooling coils, and then apply the foil layers by hand. Or spray them onto it. Or more likely spray the insulator, and layer the conductor.
