Stop-Motion Puppet Fabricator
URETHANE MOLD
Zombie Hand: Personal Project
* Responsible for all fabrication.
The purpose of the zombie hand was to test out a three-part urethane hand mold, similar to those made at Laika, Shadow Machine, and other stop-motion studios. The mold has a small key that is sandwiched between the two main halves. The small key holds the armature and ensures that the registration is secure and does not budge when doing the final squish cast.
Part 1: Armature Key
Sculpt: I first sculpted the armature key in Medium Chavant Clay. I placed a 7/32 K&S Brass Tube in the center that was 3/4" exposed. The sculpt was sprayed with Crystal Clear.
Mold: The armature key was molded with GI-1000 Silicone. This would allow me to cast extra parts for future molds or if the part got damaged.
Cast: The part was cast with TC-1630 Ultracast. Ease Release 200 was applied to the mold. A brass tube that was drilled to receive a 4-40 bolt was placed in the existing void.
Part 2: First Half
Clay-Up: Before starting the clay-up, I applied Crystal Clear to the sculpt and marked the center points of the hand with a sharpie. The hand was secured to the armature key with a 4-40 bolt and nut. Pro-Poxy was applied around the bolt and nut to create a void for future casting. Jolly King was used for the clay-up.
Pour: Ease Release 200 was applied to the sculpt, clay-up and armature key. TC-1630 Ultracast was pour directly on the armature key. Air was gently applied to the sculpt, focusing on the area in-between the fingers. This helped with bubble prevention. Assisted by Thaddeus Varness.
Clean-Up: Once the urethane was cured, walls were removed and the Jolly King was carefully removed. Using alcohol, I cleaned up any remaining clay on the surface and around the sculpt.
Part 2: Second Half
Trenches: Before pouring the second half, I added trenches and chisel keys using Jolly King.
Pour: Same routine as the first pour, I applied Ease Release 200 to the sculpt, clay-up and armature key. TC-1630 Ultracast was pour directly on the armature key and air was gently applied to the sculpt, focusing on the area in-between the fingers. Assisted by Mane Harutyunyan..
Opening: Once the urethane was fully cured, the mold was opened. The two halves released from each other very easily. The armature key needed a bit more force before it released itself. The part was slightly damaged, but I was able to recast the part and it fit perfectly.