Well that's assuming it's completely solid and not hollow. Hollow would probably be pretty huge, although the structural rigidity might not be great. Maybe we make a giant obsidian 3D printer and print it at like 10-15% infill.
An obsidian 3d print is less crazy than you might think. It's essentially rapidly cooled lava.
Need something to hold the lava, then pressurize it to squeeze it through a nozzle that that has attached cooling units.
Well that's assuming it's completely solid and not hollow. Hollow would probably be pretty huge, although the structural rigidity might not be great. Maybe we make a giant obsidian 3D printer and print it at like 10-15% infill.
An obsidian 3d print is less crazy than you might think. It's essentially rapidly cooled lava.
Need something to hold the lava, then pressurize it to squeeze it through a nozzle that that has attached cooling units.
I think you just described a volcano.
We're in luck! They already sell that nozzle!
Simple: bucket of lava, bucket of water, repeat.
Grabs a bucket. Quick, to the lava depository!
Using a planet for a 3d printer's nozzle still sounds pretty crazy.