Last modified: Saturday, January 6, 2001 6:20 PM



From the guestbook, writes:

"...clicking around i found this site : he makes his own fully jointed silicone bodies, no visible joints or seams! The possibilities for this are limitless, although there are a few pics of the process, I still have lots of questions..."

(I was going to address this elsewhere but the text just got too long. Besides, even though I've talked about this before, the topic does deserve its own article.)

06/02/00-- Wow, another cool site pointed out by a website visitor... Many thanks,!

I didn't see any in-process pics there, but the newer projects show the figures posed with what appear to be seamless shoulders and knees. From my non-exhaustive browsing of the site, I must confess that I don't know what's going on. The photos don't reveal "unclean" detail like molding seams, I didn't see a naked figure, and you don't get a feel of how the figure actually handles. However, if you don't mind seeing some sexually explicit examples in 1:1 scale, check out (We're all adults here, right?). The pics there give you a good idea of what goes into making a figure with skin. (Sorry, but there are just so many innuendo joke possibilities, I'm not even going to try!!!) I believe that silicone is used for the realdoll figures; silicone is more durable than flexible urethane and doesn't stain or discolor as easily ( restraint...). However, you do have to use a special silicone-based paint since nothing sticks to silicone except for silicone. There are also likely to be some physical property differences in the way the materials act at 1:1 and 1:6 scale. For example, at 1:1 scale the weight of the material necessitates a very strong armature/skeleton. That's not as big a problem for 1:6 scale figures. However, the material's weight & mass at different scales don't always work in your favor.

It's helpful to look at examples of toys manufactured like this, such as the way seamless legs are done on some figures (like the "Zena" figure and the "Hall of Fame" body style). These use a plastic articulated skeleton embedded in a solid flexible material. My guess is that the flexible material is cast around the skeleton since the exterior has casting parting lines and cutting the leg apart shows that some material flows through openings in the skeleton. It seems that this implimentation is almost universally despised: Because of the plastic coating, the legs don't have a great range of articulation, and most often they're held in poses by noticible "click stops" (when they work). The rigidity of the flexible plastic fights the poseability, so the interlocking mechanism is needed to lock the hinge in position. Flexible wire embedded in a flexible casting (the "Gumby" method adopted by Dragon for poseable fingers) don't have this problem to the same extent. The reason is that the bend is more gradually distributed throughout the flexible material, so it's not required to compress as greatly (and stretch on the opposite side) at a single point (at the sharp angle of a hinge). Using a softer, more flexible plastic would alleviate some of this problem, but softer flexible materials are less durable.

Flabbercast is one of the softest castable materials I've ever used (the consistency of jello), but it's not appropriate as an exposed surface material. The softness comes as a result of its low density, and it cures as a sticky, perpetually "wet" material which can be torn by pinching. The effects of scale are also worth noting. At 1:1 scale, Flabbercast can be used to simulate the "jiggle" of fat, but it doesn't work scaled to 1:6th because there's not enough weight and mass.

Another approach is to use a thin skin, like the "sleeve" on Dragon's Cheong figure. Again, the verdict is mixed on this approach. When the hinge is flexed, the skin puckers and wrinkles very unnaturally. It too will restrict the articulation because flexing it compresses material on the inside of the hinge and stretches it at the outside. The flexible material would prefer to be in its natural, uniformly thin state. You run into this problem when dip coating with a flexible compound too.

These problems come from the fact that the flexible material is just laid on top of a rigid skeletal armpiece without a layer of soft tissue to modulate the stretching of the skin. When you bend your elbow (I mean your real, flesh & blood elbow), the elbow area gets wider at the sides as the tissue redistributes itself, This points to an intriguing solution: Model the figure the same way the real thing is built. This means an articulated skeleton covered by a supersoft cushioning material covered by a flexible but durable thin outer skin layer.

Construction-wise, this is not an easy thing to do. The articulation armature is a fairly straight-forward (but not easy) mechanical task, with special attention paid to creating maintenance-free and strong tensioning. In such a design, you don't need the ganged hinges of modern figures because the hinge gets an extra bit of travel from the clearance created when the tissue is redistributed.

You could use cotton or a stuffing material as the cushioning material, but it would most likely show unnatural lumps through the skin unless it were laid on in an absolutely uniform density. It would have to return to that uniformity after handling and flexing of the hinges. Therefore, it would probably be best to inject a gelatinous material (?) between the skeleton and skin, or make castings of this cushioning layer out of a supersoft and flexible material like Flabbercast. This could be done by sculpting the layer over the armature and doing the molding and casting thing. Not an easy molding job either.

The biggest problem of the outer skin layer would be in making it continous, seamless, uniform, and smooth. Naturally if you cast this, you're going to have seams between the sections (again, humans don't have this problem because we grow our skin). These seams might be concealed by costuming, or blending the paste or liquid-state material between the sections. Unfortunately, flexible materials can't be finished by inserting a patch of putty and sanding. In fact, flexible materials don't sand well at all, so patching a blemished casting could be a problem. Hollywood doesn't have this problem because a lot of prosthetics blending is done with makeup, which isn't a very durable solution. The backside finish and thickness of the skin would also be important since uneveness would probably show from the frontside as weird bulges (like our veins sometimes do). The thickness would also affect how the skin stretched when a joint was flexed. It's definitely not easy to cast a uniformly thin skin, either.

A few problems should be apparent, mainly dealing with durability. Once you've created a figure like this, tightening a loose joint on the encased skeleton could present a problem. Real humans have muscles and tendons which do that job, but in both cases, repair would require surgery. But we heal... a tear in the thin outer skin layer of a figure won't heal itself, and a realistic skin would have to be awfully thin at 1:6 scale. Finally, the really sad thing about this is that flexible materials are inherently less stable than rigid materials-- after a period of time (it varies, depending on material-- maybe 10-20 years?) with exposure to UV and humidity, they do break down, lose flexibility, and discolor. Hollywood routinely makes this kind of stuff, but doesn't create it to be long-lasting. If you sink a lot of work into something like this, you hope that it will last forever!

It probably seems like I've gone out of my way to sound discouraging and make this sound overly complicated, LOL! But IMO that's what it would take to go beyond the commercially produced attempts. If it were easy, everyone would be doing it and we wouldn't be seeing the problems of limited articulation in rubber-encased legs, or weird wrinkling in skin "gloves". On the other hand, even if you shoot for something less ambitious than the 1:6 scale cadaver I've described, you'll probably have a great time and learn lots of stuff.



This was also a good opportunity to haul my old 6" Lady Death figure out for inspection ;^). She's probably around 4 or 5 years old and was my first attempt to do something like this. Underneath, she's an articulation-enhanced multi-jointed Spiderman figure (with a few extra curves ;^). I didn't have to bother with creating skin for her arms and legs since her gloves and boots go past her elbows and knees. So the flexible casting starts at her thighs and biceps, where the clothing ends. The casting is two pieces-- front and back, glued together where it was least likely to show (along the backside). Yes, the seams look pretty funky and aren't blended, but if you don't normally see 'em, what do I care? I didn't do any of the soft tissue stuff I mentioned above, except inside her boobs, her tummy, and butt which needed it to keep the shape. The result of that omission can be seen in the righthand picture which shows the unappealing wrinkling at her thighs. Yuk. Her boobs, while compressible behind the brassiere, don't have (and never had) any "jiggle". A major bummer for me. Years of compression behind the bra have created some slight distortion (her nipples are now slightly inverted). The ravages of time have also taken some toll on the coloration: The skin casting has a yellowish tint, which isn't evenly distributed and contrasts with the purer white of the rigid plastic face casting. (I wish I could remember how I colored the skin.)

Mainly though, the big problem is how an elastic material naturally tries to unstretch and uncompress itself. You have to create really tight articulation (or notched articulation) if you want the figure to hold its out-of-rest pose. The Lady Death figure can easily be twisted at the waist, but the top-to-bottom internal spring tension isn't strong enough to overcome the pull of the stretched elastic skin in the twisted waist. So that's why the picture shows only a slight rotation at the waist between the two pics. Likewise, almost everywhere else you cover a hinge, you'll probably lose some degree of articulation as compared to an unskinned joint.

I rediscovered much the same thing while working on my 12" Teaser figure and the unnamed 6" Guyver-esque guy on the left. The monster-genre made concealing joins between all the pieces of the skin a non-issue (I did a much better job on Teaser; this guy's just Frankensteined together, and his head comes off to reveal bloody tubes) since nothing needed to be blended in the same way that a nude human would be. But I faced all the same issues of articulation tensioning fighting the elastic suit.

In all cases, the torso twist positioning doesn't stay put, and the armature would probably require some kind of ratcheting interlock. In a ball & socket joint, this would mean something along the lines of pebble-textured surfaces. Posing the waist forwards & backwards works okay because there's plenty of excess material and a place for it to go, so the skin doesn't really need to stretch or compress much. On the left, you can see what this guy's belly does when he's posed leaning forwards. The creasing is dependent on the thickness of the skin, and his belly skin is backfilled with Flabbercast. His "Popeye" forearms aren't, which is why there's such an unnatural crease at the inner elbow.

So the big question is whether all the work is worth it or not...? In some cases, it's the only way around a problem-- Lady Death's costuming was a fixed parameter and didn't allow an easy way to hide her legs' articulation seams. Same with her shoulders (although I mainly keep them covered because I goofed and gave her too much "waddle"). Some of these concealment tricks are just much easier to do with costuming, where articulation doesn't get compromised as severely. Yet another strategy is to write off some areas of articulation and concentrate on the appearance.

So back to's remark about the limitless possibilities of skinned figures-- I think it's better described as just another technique to trick your way around the various problems you encounter when creating figures! As usual, there are lots of trade-offs, with no perfect solutions.




06/07/00- As Rosannadannadanna sez, "Nevermind..." It's not easy to find your way around a site written in a foreign language that you don't speak, even if your browser can handle the double-byte language encodings (which mine can't). Thanks to Victor Mula, I was steered in the direction of finding those "making of" pictures at the website, and the links to the pics were nestled in amongst those cryptic symbols. I would have never found them otherwise, so I'll cheat for you and give you the links here: [pic 1] [pic 2] [pic 3] [pic 4] [pic 5] [pic 6] [pic 7]. It's bad netiquette to do this, but since I'm telling you that they aren't my pictures, maybe I'm forgiven for the transgression?

My original text only briefly guessed at how the figures were created, but with these pics it's obvious. This is the "Gumby" approach; a wire armature embedded in a solid casting of flexible material. Since I can't read the captions, I can only guess at the explanation. Pic 1 is probably the clay master used to create the two-part silicone mold shown in Pic 2. (Note the vent holes at the extremities and shoulders, and the pour hole at the top.) Pic 3 looks like an aluminum wire armature which is to be embedded in the casting. Pic 4 is the jig used for holding the molds while pouring the casting. The armature needs to be carefully positioned in the center of the mold, and from the picture of the mold it looks like grooves have been cut in the mold at the hands to align the armature. If pouring silicone in a silicone mold, a barrier coating needs to be put on the mold so that the casting doesn't become part of the mold. If one material's urethane and the other's silicone, that's not a problem. The other pics you can figure out for yourself...

The results are stupendous, and this is beyond doubt the finest looking Gumby I've ever seen. The project is ambitious and whoever made it possesses a lot of knowledge and skill. If your sculpture has surface flaws, the casting will too and you can't just putty and sand flexible materials to fix flaws. I'm not sure whether the pictures represent the actual order of production, but I would probably create the armature first, sculpt the body over it, make the mold and remove the clay. That way you'd be sure that your mold would match the armature exactly. This would also be a fairly expensive project since the mold itself uses quite a bit of rubber. The figure does too, and you rarely get perfect castings the first time (dunno why, but it seems so).

I think that most of my original commentary in this article about the subject is applicable. Wire doesn't pose like a real skeleton and repeated bending will weaken the wire. There's also the potential problem of a wire end tearing through the rubber if the rubber's really soft. Why not use an articulation armature instead? The armature's joints would need to be very stiff and strong to hold a pose if encased in rubber. It takes much more force to bend aluminum armature wire than it does to bend a hinge; therefore, while fighting the elasticity of the rubber, the wire would stay bent into position more readily than a hinge.

That's the rationale behind using an articulation armature underneath a thin rubber skin instead of embedding it in a solid casting. Since the skin is thin, it doesn't fight the articulation as fiercely. Unfortunately, it's not easy to cast an entire body as a thin skin since flexible rubbers usually take many hours to cure. Unless you've got a mechanized slush or rotation casting rig, you're not likely to have the patience to manipulate the mold for as many hours as it might take for the casting to gel. And this of course means that your armature has to be put in after the skin has cured, so you're facing some kind of patch work anyway. Assuming you've gotten that far, it then is possible to pad the interior space with an extremely soft, gel-like material so that your figure doesn't look like a deflated balloon.

Still, this type of project (however it's attempted) is a good test of your skills as a figure maker, and starts you down the path of becoming an animatronics or special effects guru or guru-ette.