Mold Making question. I seriously need some help

Discussion in 'Replica Costumes' started by jmedina, Aug 27, 2015.

  1. jmedina

    jmedina Member

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    So I decided that I would make a batman mask. I purchased a red Plastalina clay, because I read that it was sulfur free, After completing my sculpt, I purchased Smooth On Rebound 25 to make my mold. I sprayed the surface with 2 layers of crystal clear and then applied 4 layers of the silicone after crystal clear dried. After 2 days to let the silicone cure, I made a mother mold out of UltraCal 30. I successfully demolded the mother mold. Upon demolding the silicone I noticed that where the silicone touched the clay the surface is still very tacky.

    I live in Florida, and the weather has been extremely hot, humid and wet as of late. I applied the silicone indoors with the A/C on. Temperature inside the house is about 75 on average. If the clay contains no sulfur what could be causing the silicone to remain tacky? Do I have any chance that the silicone will fully cure? Or am I screwed?


  2. logan74k

    logan74k Active Member RPF PREMIUM MEMBER

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    If you got it demolded without damaging the silicone surface, (IE it's just tacky and not still liquid) it might be possible that it will still cure. With the pattern out, I'd put the mold (supported by its shell) in a box oven at 160 or so for a day, and see if it's any better.
  3. Junklady

    Junklady New Member

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    My guess is the measurements were off or not mixed well. When I first started out, I would eyeball the measurements until I had a silicone mold that wouldn't cure. I made a great investment in buying a kitchen scale and now I can get precise measurements.
  4. SithariRog

    SithariRog New Member

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    I've had some trouble with silicone setting when I used certain types of paint. If memory serves, I used a white glossy pain to cover a master prop, in order to make it ultra smooth, and the silicone layer against the prop didn't set well. I sanded off the paint and went with my usual clear coat, which has worked. I did some experiments to test this theory, and did, indeed, find that the paint was the culprit.

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