I've heard of that approach. Not sure if it was Clarke, I always figured you'd need a lot of pressure to do that and it would be tricky to stop it from leaki

I've heard of that approach. Not sure if it was Clarke, I always figured you'd need a lot of pressure to do that and it would be tricky to stop it from leaking out holes. Another idea I had was making a sphere of chicken wire around a small comet. If you melted the comet would the water go out and condense onto the chicken wire eventually making a huge hollow sphere of ice.