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How do I mold an elastic part for cheap?

  1. Mar 19, 2015 #1
    Hello. I'm an engineering student so don't make fun of me. I'm trying to mold an elastic cylinder. My plan for doing this is to:

    1. Print out a plastic mold.
    2. Buy elastic material.
    3. fill the mold with elastic material.
    4. wait 24 hours.

    I'm trying to make the cylinder as elastic as possible. Which material should I use? Can this be done at room temperature in order to prevent the plastic mold from melting?

    Please help. The more information and advice I can get the better. Thank you.
  2. jcsd
  3. Mar 19, 2015 #2


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    Staff: Mentor

    I have very limited 3-D printing experience, but can ask a couple questions to help other responders.

    What size is this cylinder going to be? How elastic? What is the application? Can you just 3-D print the elastic cylinder directly?
  4. Mar 20, 2015 #3
    Don't they make a pourable silicone rubber that is suitable. I know that Myth Busters and Hollywood use this stuff all of the time.
  5. Mar 21, 2015 #4
    I'm an engineering student, too, so you won't get trouble from me. It sounds like your approach would work pretty well with RTV silicone, which has a very low elastic modulus (http://www.matweb.com/search/datasheetText.aspx?bassnum=O5200). As long as you wouldn't mind cracking the mold to get it out, because it's pretty tacky before it cures, then it could do the trick. It usually cures within 24 hours.
  6. Mar 24, 2015 #5


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    Staff: Mentor

    Good suggestion! One of those tubes of handyman gap sealants or caulking compounds should do, they set to a tough rubbery solid. You can buy them in a range of colours, or clear silicone. Intended to be slotted into a caulking gun (or whatever it's called) for application.
  7. Mar 25, 2015 #6


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    Science Advisor

    There are many two part silicon based polymers formulated for use in moulding.

    Start with a google search for ' making silicone molds for ' and see where it leads you.
  8. Mar 30, 2015 #7
    There are a bunch of ways to do this, but RTV works good.

    People in the art area, (casting) use this stuff a lot.
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