Thanks fellas...
Today I've decided to bite the bullet and order some commercial spray foam insulation (closed cell foam) that has a 3:1 expansion rate that I'll use to build up the bear's anatomy to where a final skin of clay (approximately 1/2" thick) will allow for final detailing of fur and other critical details. Use of the foam will add less than 30 lbs of weight to the overall model plus give it structural strength to support the clay more evenly over the entire structure. The clay will add probably another 200 lbs. What I don't want is the weight of any clay used to cause the structure to lean off balance and distort the "stance" I want it to have. If that begins to occur I'll have to install support rods attached to the base and at various points of the body to ensure the positioning of the anatomy remains intact.
Once the detailing is done I'll seal it with a release agent then spray on (or brush on) a layer of RTV rubber as an initial mold that will be done in removable sections. Then the task of spraying on a durable "plastic-like" mother mold over the RTV rubber inner mold pieces which will ensure the inner mold layer stays registered to the appropriate shape.
Then comes the daunting task of disassembly of the mold pieces and painting the inner mold sections with molten wax to build up the actual "final" wax model impression I'll use to invest, burn out, and cast into bronze each of those sections (which will entail numerous pieces). At this point you know the rest which requires reassembly of the bronze sections by welding/brazing, etc. and finally doing the last bit of detailing of chasing all the welds and imperfections, devising and installing anchor devices for mounting the sculpture to a base, coating it with a nice rich chocolate brown patina, buffing highlights, and FINALLY sealing the entire sculpture with a preservative clear coat.
This is basically what I did a while back when I created that BALTO Dog sculpture, except I did that mold with plaster only, painted the interior of the plaster shell with wax, removed the wax, reassembled the wax to a full body representation again, then cut the finished wax model into sections that would facilitate casting with the crucible volume I had to work with. Each of those wax sections were gated and vented with wax rods (3/8" to 1/2" thicknesses) then each section was invested in plaster and the wax burned out and cast of bronze. Reassembly of the bronze sections was liken to what I described already regarding the bear.
When it comes to sculpture there's no way around it, ya got to build the damn thing four times... i.e., the initial model, then reverse building as a negative shell, then build it again in wax sections, then again in bronze sections. Now you know why sculptures cost so damn much, HAHA...
The added benefit is then having a permanent mold to use for duplication afterward, if not as the original design, one can duplicate pieces of it to use to help expedite another work of similar composition. You know what that'll lead to, though, don't'cha? .... yep, need of mold storage space, i.e., another shop extension!! HAHA...
The spray foam will be arriving first part of next week. The build up of that bear's anatomy should only take a day; carving back excess foam to ready for the clay surface details should only take another day or two. Application of the clay skin layer will take a couple to three days. That's, of course, an ideal scenario not necessarily a given in what may or may not be required. Like a woman giving birth to a child, it'll happen in its own time. The more one attempts to force it to happen the more risk there is of complications.
I've been dreaming and getting my mind prepped for this for over 8 years. I need to stay focused and not waste any material due to mistakes made in haste. Progress pics will commence once the foam is being applied. I am soooooo Jazzed right now I can't begin to describe the flurry of thoughts and excitement my mind's goin through.