I had some thoughts on how to casting a hollow Tie fuselage, this maybe over complicating the issue, but here goes. This uses a version the solid steel rod mentioned above, but with a twist.
Materials needed:
1 Styrofoam ball from a craft store
2 Sections of Brass tubing
1 Steel rod sized to slip inside the brass tubing, it should be longer than the finished part.
Make a shih kabob using the steel rod as the skewer (the rod will need to be lubed to prevent it from sticking), brass tubing, styrofoam ball, brass tubing, insert this assembly in to the mold. After casting the styrofoam ball can be dissolved with acetone or similar solvent friendly to the resin.
The brass tubing should be left a little long and the wings can be mechanically attached to the brass tubing.
Any thoughts?
Alan