Infojunky said:
Might I point out the was a long discussion about building ship's hulls by molding them. Casting is problematic above a certain scale in that hull would need considerable post molding work to finish just the hull. I believe that conversation was on this board in fact.
On a slight turn of topic, what would be the advantage of a Ceramic hull?
If it were up to me I would make more resistant energy based damage, i.e. Laser and plasma weapons.
Larry Niven recommended drilling a shaft into the centre of an asteroid, setting off a nuke or two to hollow it out, and then moving in once the thing had cooled down.
Er, yeah ... okay ...
Hollowing out a rock to make a ship or a space station would require specialised mining equipment to go in and drill out the required cavities, GPR and other sensors to detect internal faults, and then of course there would have to be the installations - Bridge, life support, crew rooms, drives, power plant, all of that.
It would seem to be just as cash-intensive to do all that as to 3D-print an egg-shaped concrete or ceramic hull using finely-ground vacuum-welded silicate/nickel-iron composite over an assembled internal framework. Put all the rooms together, clamp the mould around the framework, then fill the thing with your concrete slurry, let it set in the vacuum of space, and finish off with precast cargo bar hatches and covers.
It sounds just as science fictional as turning a rock into a spaceship or space station. Maybe in your setting, some species actually do that, rather than hollow out internal hulls.
That's the "making" part, and it's really only for the all-out concrete ball-type rock ships. If it's an actual planetoid that was hollowed out, I can still see navies spraying aggregate over the cracks and splits in the hull. It'd look ugly, and it'd look like an obvious patch job forever if the aggregate was of a different composition to the native rock, but it's not exactly as if the ship was pretty in the first place.
The one thing I'd like to note is that these materials tend to be great heat insulators. If something really hot pierced the hull, partially glassed it in a part, that place would be too hot to go near for a long time.