Silicone arms

Drewskiman
Drewskiman ✭
in Props
I seriously need some help. I've attempted to make silicone arms 10 times now with little success. Either I have to destroy the mold because it's sticking too much or it's too thick or thin and doesn't come out right. I'll make a mold of my arm using body double standard and I'll mix in hyperfolic so it slides off. I use 3 coats. The first coat is with the additive and the other 2 with no additive. Afterwards, I'll pull it off my arm and I let it air dry for awhile. I put in 6 coats of 205 and I let each layer dry for at least 2 hours before adding the last which I'll keep a little damp before I pour my silicone. A friend of mine who does this for a living told me step by step what to do and my previous explanation was it. I can't add wax or anything because I can't get down into the fingers or hand obviously. Can someone please tell me what I'm doing wrong. I even keep the room in working in at least 75° at all times. Am I letting it dry too long? Do I need to lessen the time frame?

Comments

  • Chris Ellerby
    Chris Ellerby Admin
    Normally when casting a flexible part you want a rigid mold, and it's usually best to avoid casting silicone in silicone. 

    To get there you would first lifecast your arm as you are doing now, then cast it in a melted clay like monster clay.  Once the clay cools, you can de-mold it from your silicone life cast and start making a 2 part epoxy and fiberglass mold of the clay arm.   Once you have the 2 part mold, you can lay up clay inside the mold to represent how thick you want the silicone to be in those areas and cast a mold core that registers and locks into the 2 halves of your epoxy fiberglass mold.  Next, you can clean out the clay, drill small bleeders where you think air might get trapped, add a pour spout/injection point, lock the 3 pieces together, bolt the mold shut, and fill it with silicone.  As the bleeders let the air out and start to drip silicone you can seal them up with clay.

    Optionally you can also make a power mesh sleeve and slide it over the mold core to help reinforce the glove.

    If making a mold core is too complex a task for what you have in mind, you could just rotocast silicone into the mold until you build up the desired thickness, however, it will be hard to control how the silicone builds up in different areas.   You could also brush in silicone in each mold half to build up your desired thickness, then join the mold halves together, and rotocast with additional silicone to join the halves.

    This course covers lifecasting hands, which may be of some help:
    https://www.stanwinstonschool.com/tutorials/how-to-life-cast-character-creation-tutorial

    This course can help you with the molding and casting:
    https://www.stanwinstonschool.com/tutorials/silicone-mask-making-part-1-epoxy-fiberglass-molding-a-sculpture

    /Chris
  • Drewskiman
    Drewskiman ✭
    So basically make your arm mold then fill with monster clay then make a 2 piece epoxy mold. Is there a different between monster and alien clay?
  • Chris Ellerby
    Chris Ellerby Admin
    Alien clay is a slightly different clay formula.  I have no experience with Alien clay yet, so I don't know all the differences between the two.

    /Chris

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