Mold making SOS

Blake BradleyBlake Bradley ✭✭
edited October 2016 in Sculpture
Did the mistake of creating a Tin cure silicone mold from a sculpt that I wanted to cast platinum (Ecoflex 30). I learned that platinum won't set up on tin, so Im a bit stuck. I'd like to just make a new mold with a material that's compatible with platinum silicone. I destroyed the original sculpt without thinking this would happen, so I took the existing Tin mold I have and casted an oil based clay (monster makers clay) into it. I can make a new mold from this oil clay casting. I'm worried that since the oil clay casting has been in contact with the tin mold if I made a platinum mold from this cast it it won't set up because the clay was in contact with the the tin mold; true or false? Anything I could do to "waste" the tin residue off of the new oil clay cast if this is going to cause a problem? Hope this makes sense!


  • Chris EllerbyChris Ellerby Los Angeles Admin
    If you want to make a new mold from the clay, spray it with something like krylon crystal clear to seal it up and prevent contamination.

    You can cast from the tin cure silicone mold if you have a good barrier of release agents (waxes, PVA, etc) but it's always a gamble.

    Just to be safe (and not waste your casting materials) I would go ahead and make that second mold using the clay casting and seal it up nice and good with the krylon.

    Best of luck!  (And I hope you can share your results with us)

  • Blake BradleyBlake Bradley ✭✭
    edited October 2016
    @Chris Ellerby Good idea! I'll let you know how it works out. Do you have any suggestions on what material to use for the new mold? 
    Post edited by Blake Bradley on
  • Chris EllerbyChris Ellerby Los Angeles Admin
    Since you are casting a flexible part you can use a rigid mold, like fiberglass or epoxy.  

    You could also make a platinum silicone mold and use a lot of release agent to prevent your castings from bonding to it.

  • @Chris Ellerby Do you know of a good platinum for moldmaking? Would rather not go with a top dollar for just the mold.
  • Chris EllerbyChris Ellerby Los Angeles Admin
    Smooth-On's "Mold Star" silicones are a great platinum silicone for mold making.  You may be able to shop around and find cheaper silicones, but you could be gambling on the quality unless you know the brand.

  • David BoccabellaDavid Boccabella Innisfail, Australia Moderator
    Actually I just added to a separate discussion re molds and skin making.

    I often use  Gelatine to make a test skin since it is biodegradable, easily cleans in water, endlessly reusable, and can be lifted so you can modify the underform re skin thickness.


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