submitted by Mike Brent
Here's a nice little mini-tut I just found on the Sculptor's Forum whipped up by master sculptor Erick Sosa with text provided by super-talented up-and-comer Trevor - um, well sorry Trev, I don't know your last name buddy. This is a technique used by toy sculptors who need a lot of detail in a small sculpt, and wax is firm enough to allow carving all that detail without smashing anything while you work (which can be a problem with polymers or plasticenes). So to get the best of both worlds, they'll often do a rough in super sculpey and bake it up, then transfer into wax to go to town and do all the ultra-detailing.
The reason I'm posting it here is because wax can be a great product for casting replacement heads. It's common practice to sculpt a head and then make a silicone mold from which you would pull a series of wax castings that you can modify with steel tools heated over an alcohol torch. You can also dribble melted wax on with a tool called a waxer or a wax pen... I've never used one, but they say it's the closest you can come to drawing in 3 dimensions. You add wax where you need it and then carve it down and polish for an ultra-smooth surface. The ultimate wax pen is the Kerr Ultra Waxer, but most people go with the less expensive but still excellent Foredom Waxer. Both are available through Kingsleynorth.com
Well, without further ado, here are Erick's pics followed by Trevor's explanatory text:
"Silputty is a two part rubber for making quick molds.
in the first photos, you see Erick took equal amounts of the green and white parts of silputty and mixed them thouroughly. all you do after the stuff is mixed is pack it all around your piece (the head in this case) you can leave a small hole at the bottom of the neck, or do what Erick did, and just cut a hole after it sets up
the silputty sets up in half an hour, but that's more time then you'll need to work. it's very very soft so it packs in around your sculpture pretty well...I've never transfered anything with much detail, I just use the method to save time building up wax.
after it's set up, you cut a zig zag pattern on both sides of the mold to create a key so that when the mold is ready to be poured, it stays together. pull the sculpey rough out, and you're ready for the real fun!
I use Ralphs TMS wax, and for some reason it can sort of stick to the silputty. Other waxes might not do this. in any case, I rubbed a thin layer of vaseline inside my mold to prevent it from bonding to the wax. after you do that, you tape up the molds...the only tape that I found that sticks to the silputty is a duct tape, but it looks like Erick uses something else. anyway, the idea is to tape the mold really well so that it stays together and won't leak....leave the pour hole open of course.
after it's taped, you just heat up the mold with a heat gun/blow dryer. first you'll want to get your wax heated up and ready to pour. after you've warmed up the mold, slowly pour the wax into the opening at the base of the neck. you'll want to go to the brim, as the wax 'sucks' in as it cools. after it's poured, you just stick it in the freezer for 20-25 minutes. it's ok if it's still warm, in fact i find it's better if it's slightly warm. Then I just cut the tape off, and gently pry the mold open to pull the casting out.
I got five generic head pours out of one mold, and I could have gotten a few more if I had been more patient, so it can be a real time saver!
might have missed some details, but that's the basics! don't be intimidated, it really will seem easy after just doing it once"
Ok, Strider back. Time for a products listing:
Here's a good toymaker's wax made by the same company that makes the Silputty - Silwax
Unfortunately that company doesn't seem to offer an online catalog... you have to "call for pricing" and order over the phone - dealing with salespeople etc. If you're looking for more convenient online ordering try The Compleat Sculptor. They carry another toymaker's carving wax called Azbro Wax. Be sure to check that page for some good tips and info related to working with carving wax. TCS also carries a different brand of silicone putty similar to the Silputty called Resilpom.
For more on working with wax and its use for making replacement heads for stopmotion, see Marc Spess' Wax Article .
One thing I should mention is that the molding method illustated above is good for one-offs or sculpts that don't need to all be identical, but if you want to make a series of replacement heads (which is often done using wax) you'd want to use a different technique, because the zig-zag cut in the mold results in a pretty imprecise casting that needs to be cleaned up and each head will look a little different. So for replacement heads you'd want to use a liquid silicone pour with a mother mold. You can find techniques for that in the sculpting/moldmaking section of the handbook. Also, you'd want to incorporate some kind of registration device ino the mold to ensure that all the heads will register exactly the same on the neck. There's some good info on this provided on a thread started by Josh Jennings called Replacement Heads. (not available at this time)