EGO --- You dork
MMM - It's totally the right idea. And it's the method of choice with most resin sculptures with varying odd shapes. But allow me to attempt to refine the process a little ...
With a 2 part silicone mold, one could achieve exactly this, with urethane resin.
By pouring into the first mold half, while the resin is still in its liquid state, you rest your skeletal structure of choice in the uncured resin, taking care not to allow the structure to touch the bottom of the mold, by propping it up. This falls into "Suspension Molding". Once the resin has cured, the piece can be removed, and you have a fully formed detailed half structure, with a skeleton sticking out the other side. Then, take your other mold half, pour your resin, and while it's still in it's liquid state, you take your other completed half, turn her upside down, and drop the skeletal side into the resin, allowing the hardened resin shell of that piece to rest on the flange of your silicone mold ... suspending the skeleton in the liquid resin, without allowing the skeleton to touch bottom of the bottom mold ... .again, "Suspension Molding" When cured, you pull your piece, and you have solid resin sculpture, with a full reinforced internal skeleton.
The only trick to this, is to design the skeleton slightly thinner in diameter that the structure will be when the two halves are assembled.
The reason I suggest the suspension method, is to allow for detail on the bottom of your casting. You need a retaining wall anyway, so it might as well be a detail mold, rather than blocks of some sort.
But, it's the same concept, nevertheless
The downside, is still the weight. Extremely heavy. And, in the grand scheme of things, is still much more brittle, because the resin can still crack if dropped .. this is physics. The weight of itself, in relation to the shore hardness of the resin = disaster. With fiberglass, you have an extremely durable structure, that is a fraction of its own weight (hollow) in relation to the the shore hardness of polyester resin that's been reinforced with glass matte.
If one were to make a rifle using the resin suspension method, and another made of fiberglass ... one could test the theory with a small car ...(don't laugh, I've done it
)
If you back over the resin rifle, it will spider crack around the skeleton .. stress fractures ... (it would just break if it were solid) and the fiberglass structure, would be unaffected .. not only because of the material used in the structure, but because of the shape. It tends not to cave in, because the structure is stronger with curves and bends in it's design, stronger in fact than a structure that was a mere rectangle for instance. Sometimes it's hard to put into words what you have rolling around in your head, so I hope that makes sense
FP