After running the multi-part digital marathon on our latest explorer boots, we’re moving up the limb to tackle the next big hurdle for our full-body lizard puppet: the hands.
At a glance, stop-motion hands look simple. In reality, they are the hardest-working components on a miniature set. They are constantly bending, gripping tiny props, and taking absolute punishment frame after frame.
To get these claws production-ready, we had to do another precision software dance between ZBrush and Fusion 360 before moving to the physical casting bench. Here is how Phase 2 came together under the workshop lights.
Phase 1: The Digital Sculpt to Mould Matrix
The pipeline always starts in the digital design suite. In ZBrush, the hands were organically sculpted to strike a balance between stylistic character design and the physical limits of stop-motion movement. I wanted a heavy reptile scale texture running down the back of the hand, contrasted against smooth, fleshy palm pads on the underside.
Caption: Smooth palm pads versus rugged ZBrush scales—the perfect combo of mechanics and aesthetic.
Caption: The initial 3D mesh exploded in ZBrush, prepping the negative space for the resin printers.
Once the sculpt was locked, the asset was brought into Fusion 360 to engineer a rigid, two-part mould box complete with interlocking registration keys.
The secret weapon in this digital mould design is a tiny, dedicated registration channel at the base of the wrist. This channel holds our internal armature wire perfectly dead-center during the pour, making sure the skeleton never floats too close to the surface of the skin.
Caption: The engineered two-part mould layout designed in Fusion 360, ready for the Elegoo Saturn printers.
Material Science: Upgrading the Skin
When we cast standard character skins or soft body parts, our default is usually an ultra-soft compound like Platsil Gel 00 for maximum realism.
But hands are a completely different beast. Because they face constant handling on stage, casting them in an ultra-soft gel is a recipe for tears and structural warping. For our lizard friend, we stepped up the structural toughness and opted for Platsil Gel 10. It gives the claws a thicker, more durable finish that handles stage wear like an absolute champ while still preserving that vital organic flex.
The Two-Tone Injection & Pour Strategy
To get those clean, two-tone lizard hands without playing a nightmare game of surgical masking, we used a layered casting technique right on the bench.
First, we mixed a batch of light green pigmented silicone and used a syringe to carefully inject tiny, precise amounts directly into the palm and finger pad recesses of the mould halves.
Platsil Gel is brilliant at chemically fusing to itself, even days after curing. We let those light green pads cure completely for about 30 minutes on the bench so our wire finger armature had a solid foundation to rest on without cutting through the skin.
Caption: Syringe-injecting the high-detail finger pads before laying down the internal skeleton.
Next came the skeleton. For the internal articulation, we used twisted 0.5mm fabric-covered steel wire. Standard slick wire slides right out of cured silicone, but the compound adheres to the fabric layer beautifully, locking the bones completely in place.
With the wire skeleton resting safely on the cured pads, we used a classic pour-and-spread technique to coat both halves with our darker, de-gassed forest green silicone batch. We let the mix get slightly tacky to let any sneaky residual air bubbles escape, then bolted the halves together inside a custom metal clamping block.
The Final Pull and Polish
Thanks to the absolute accuracy of the resin prints and the registration keys engineered in Fusion 360, the cured casts pull away with little to no flashing along the seams.
Caption: Freshly pulled casts right out of the clamps. Flawless registration with razor-sharp scale detail.
To give them that ultra-premium, production-grade finish, we took the raw casts to the vice and buffed the minimal seam lines with a custom Dremel tool.
The final result is a set of rock-solid, incredibly expressive claws that plug directly into the forearm rotary joints of our character armature.
Caption: The completed hands mounted and ready to cause a ruckus on a stop-motion stage.
A Note on Workshop Reality
Here’s a bit of unvarnished truth from the bench: no matter how perfectly you engineer them, stop-motion hands are ultimately consumables. Under the relentless stress of an animator's fingers, the internal wires will eventually fatigue and snap.
But with a rock-solid digital pipeline, printing a fresh set of replacement moulds or casting a backup pair from our locked ZBrush files takes no time at all. We don't just build puppets to look pretty; we build them to survive a production.
The printers are already clean, the bench is wiped down, and the full puppet assembly is up next on the slab.
— Jools