The nice thing about this construction method, is you can use it for all kinds of ship sizes. These little pukes will wind up as fighters:
And this big bad boy is going to make for a fine capital ship. That egg looking thing is a toy package for a dragon. It had a cool 'veiny' look to it that will add to the feel of these alien ships/critters.
Again, remember that the foam keeps expanding as it dries. The above is a picture taken just after 'spraying'. The next one is a shot of the ship after it is fully dried. Note how much bigger and smoother it is - not entirely smooth, but more than the above.
And you can build ships in between as well. See those cupolas? Yeah, you really want to either spray foam on top to keep them in place, or wait until the foam dries before sticking them on there.
I'll show you why next time...