I've been slowly learning how to sculpt and make molds and cast stuff into those molds.
Body casting, I'm pretty good at now. I've found the mix of (bloody expensive) materials that I like, and I get great results most of the time. I only pull all the hairs out of my fingers when I forget to use mold release... and I usually forget to use mold release on myself. I forget mold release a lot... but the hairs usually grow back, so I guess that's okay.
My sculpting has also gotten better, I'm quite pleased with the results I've achieved this year. I have some absolutely lovely wiggly eyeballs on optic nerves, with bits of muscle and bulging veins and the like... not really lifelike but quite evocative. They will be wonderful fun to terrorize people with!
I've got a very nice heart, too. My current heart mold isn't really to my liking; the heart is too small, the mold is a bit fussy to work with, and there aren't enough bulging veins and long wiggly bits. My new heart sculpture has a bit more extension on the veins and arteries, is a bit larger, and is quite pretty I think. It's not _lifelike_ because real hearts are boring, blobby things; but it looks a lot like an anatomical model, because that's what I used for reference. Drawings, an anatomical model, and yes, photographs of real hearts. I'll be doing work to the silicon cast to put on fat blobs and other life details, which will help.
Finally, I have a new brain sculpted, for the same reasons and with the same basic changes as the heart.
All very nice. My skills improve each time, and I'm almost confident enough to tray, I dunno, a face or something.
No matter how nice the models, the rubber really hits the road when making the molds. I've spent untold HOURS making these sculpts -- art is slow, painstaking, and ... slow. I could even use another several hours on the brain and heart, truth be told, but I just plain ran out of time.
I've made bunches of different types of molds over the years. Molds from alginate, silicon, from polyurethane, from plaster, and variations of all of the above. Molds with mother mold shells made of plastic or plaster, or plaster bandage. Good molds, bad molds, molds that I forgot to use release agent on. These last ones make great doorstops, by the way.
In the process, I've found a wild variety of ways that the process can go wrong. Not all of them, mind you, but many. If there is one talent that I am confident I have, it is in my ability to find new and interesting ways to do something wrong. I'm slowly making my way through every possible failure. Tonight, I found a new one.
I don't have my usual collection of mold-boards right now, something that escaped my notice going into this tonight. Apparently, I slowly scavenge materials from my workshop over time. So after I spent a couple of hours mounting the six eyeballs, the heart, and the brain on their little posts with vents and so forth, I had to improvise when it came to their mold frames.
I found a nice roll of aluminum flashing material in the corner, so I snipped out some strips of this, rolled them up to fit around the three individual molds I wanted to make, and taped them into place.
I then took zip-ties and reinforced the rings, so they wouldn't pop open (I've had this failure before).
I sprayed everything with copious amounts of mold release, hopefully enough, hopefully the right kind... argh! We'll see soon enough.
I took bits of foil tape and taped the aluminum rings to my work surface, around the models. I then took sculpey, which is my favorite material for doing temporary work because it is soft, handy, and I have a ton of it, and I used this sculpey to add a ring of sealing around the frames. Sculpey is great for this; I usually press it into the INSIDE of the mold to seal it, but I couldn't reach (the rings were deep and small), so I pressed it around the outside.
Experience has shown, however, that sealing OUTSIDE of something is far from optimal; the liquid pressure will displace almost anything (yes, yes, I've done this wrong in several interesting ways over the years). So I melted up some of my very stiff clay and poured it around the rings and over the sculpey. This would definitely seal things together! I was pleased with my foresight and prophylactic brilliance.
Okay, my pouring priority order was heart, eyes, and then brain. I mixed up 4kg of the translucent amber polyurethane (pretty much a full bucket) and poured it onto the heart. Not bad... just getting to the top, another inch or so.... aahhhhhhh! No! My mold frame popped up, floating up off the work surface. I squawk in outrage and press the frame down to cut off the flow. Marla was fortunately nearby and she helped me put a heavy thing onto the errant frame.
My fatal flaw was that I had wrapped my work surface in cling wrap. I've taken to doing this, for easy cleanup... so I had meticulously taped and clayed my mold frame to flimsy plastic wrap. Apparently the fluid pressure of 4kg of rather thin polyurethane in a featherweight mold frame was too much for it.
Last time I looked, I had lost maybe 1" or so of height in the mold. I'll need another 2kg to top it off, instead of the 1kg it would have needed. At least, though, it's sealed down to the work board! And the board is sealed to the table, and there are amusing puddles of rubber on my floor. I may find a few cables and tools embedded in it in the morning, like bugs in amber... maybe even a raccoon, or perhaps the spare cat. The Zeller Rubber Pits! I could be an attraction!
Anyway.
While the rubber around the heart battled it out between leaking and congealing (and, in the process, I hope it was not causing weird flow voids or distortions to the mold around the model; I've had THAT happen before, too), I mixed up the remaining rubber, some 2.5kg or so, and debated what to do with it.
I could finish the heart, and it might even stay in the mold. The bulk of what I had poured was already beginning to solidify. But I didn't want to risk it, so I poured it into the eyeballs and it was just about perfect. And no leaking, I think. I'm afraid to look.
So, 3/4 of a heart and a set of six eyeballs. I'll have eyes for Maker Faire, but no new heart. The heart and brain will have to wait for the haunt itself.
Tomorrow, I inspect the carnage in my workshop and then I order more rubber.
And I add another interesting failure mode to my distressingly long list.