No I think you've understood that correctly. I'd count that as one of those things that's blindingly obvious once it's pointed out but not until then. With 3D

No I think you've understood that correctly. I'd count that as one of those things that's blindingly obvious once it's pointed out but not until then. With 3D printing I wonder if you could insert bands of insulator into an otherwise conductive wall? But you're dealing with large (potentially ridiculously so) temperature ranges so I wonder if it would prove difficult to match the thermal properties of the two materials closely enough. I now have the weirdest desire to play with heat exchanger designs that I have absolutely zero use for. I've been nerd sniped.