I'm only so-so when it comes to making molds, and I still have real problems with plaster. Making giant heavy molds in plaster has a whole stack of extra problems relating, mostly, to the weight of the plaster.
Meaning it bursts through and pours all over my floor. I must have lost 25lbs of plaster to leaks when I made the core mold for my leg. And I don't even think I'll be USING this core after all.
I really prefer to use advanced and expensive rubbers and plastics to make my molds, but plaster is soooo cheeeap. And for some molds, I find that a block of plaster is necessary to make it work right. But for big molds, it's way better to make a (plastic) shell mold instead.
I'm making a detailed leg that will be dissected (alive) and eaten (alive) by the dead. It will have skin, a fatty layer, muscle, and squidgy viscera holding it all together.
I originaly thought to cast the skin in a tube, which requires a negative outer mold and a positive inner core mold. But upon further reflection, I fear that this approach will cause more problems than it solves, as well as wasting my precious (and darned expensive) silicon skin material.
So I think I'll go back to the method I used making the arm for HT last year, where I paint the skin into the mold in layers and then cast the guts into place. Though time consuming and harder to repeat, I feel more comfortable with it.
I still need to sculpt muscles onto the bone, cast gelatin muscles, paint the skin, and cast the whole thing together with, I think, foam gelatin.
Maybe three times.
And I need to make the (plaster, block) molds for the stomach and heart. And do a test for intestines. And work up the blood system for the leg. And a few other things I'm blocking from memory right now, I'm sure.
By Saturday at 7:00 am.
I think I officially get to panic now.
Does anyone here have experience (and I mean it, not just an interest) in laying up molds? I would farm out the mold-making for the heart and stomach in a... heartbeat.