Wanted: A liquid that hardens like a glue, but is not adhesive.

  1. I'm trying to find a liquid which will take the shape of its container, and harden like glue or epoxy. However, I would like for it to not be adhesive. This would be greatly useful to me in making molds of very small things.

    Can anybody link me to such a thing?
     
  2. jcsd
  3. I don't specifically what you would use but it sounds like it would be a gel of some kind.
     
  4. Danger

    Danger 9,878
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    Wax is used extensively for that very purpose. Try Googling 'lost wax process' or 'bronze casting'.
     
  5. chemisttree

    chemisttree 3,721
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    What kind of shrinkage can you live with?
     
  6. Ivan Seeking

    Ivan Seeking 12,539
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    Plaster of Paris?

    Foundries use wax.
     
  7. Is it a sealed container...something a 2 part application or spray foam could fill and solidify?
     
  8. f95toli

    f95toli 2,418
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    It also depends on the mould. E.g. Stycast can be cast in a split PTFE (Teflon) moulds (a standard technique in low temperature physics).
     
  9. lisab

    Staff: Mentor

    Well, if temperature isn't an issue...water :wink:?
     
  10. Danger

    Danger 9,878
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    Alginate is a very good moulding compound, Kronos, but it's fragile. During the production of special effects appliances, life-casts, etc., it's great for detail reproduction but is usually reinforced with a couple of plaster of paris coats for stability. (You can't apply plaster of paris directly to skin because of the exothermic reaction when it sets.)
    My compromise, which might actually work in this case, is liquid latex. The appliances that I'm wearing in my avatar, for example, are made by that process. I used a positive mould of my head (okay, it was a wig dummy), sculpted plasticine into the shape that I wanted, then applied 3 coats of latex. When it was cured, I used that as a negative mould and brushed 5 or 6 coats of latex on the inside. Once that was cured, I just glued it onto my face and applied standard theatrical makeup and fake hair.
    It might be applicable to KingNothing's situation, as long as the mould doesn't have to survive very high temperatures. At the very least, it will peel off of anything coated with paste wax, WD40, etc. with no deformation.
     
  11. I was thinking liquid latex, but isn't that usually used the way you did, with brush and layers? I decided not to go with that because he wanted a mold, which I took to mean more or less casting a mold which I don't think you can do with liquid latex. So I played it safe and went with something like alginate..

    They've got plenty of options though. Walking around a craft store is a good place to start though
     
  12. Well, I'm not sure that plaster of paris would work. The thing is, I want something that is quite hard when it hardens. Something hard enough for me to take a small needle or drill bit to and not have it break or crack.
     
  13. Chi Meson

    Chi Meson 1,772
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    Rock Hard Water Putty
    [​IMG]
    is ridiculously cheap, and can be found at almost any hardware store. It expands a little on hardening, and sometimes it sets a bit surprisingly fast, but it makes decent molds.
     
  14. Danger

    Danger 9,878
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    I've never heard of that stuff (and don't know whether or not it's even available up here), but I'll keep it in mind. Thanks for the tip.
     
  15. KingNothing, what you need is epoxy or polyester resin, but you need to apply a separator to the thing you're making the mold of. What will work depends on how smooth the surface is and how much fine detail you need.

    What material is the "container" made of?
     
  16. How many times have you said that?
     
  17. chemisttree

    chemisttree 3,721
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    :biggrin:

    If you want strength, you could use Type C flyash and water with 2-3% sodium citrate thrown in as a catalyst/water reducer. In 1 hour you will have 3000-5000 psi and in 24 hours you get something like 10000 psi. The mold must be small since it generates a bit of heat. The cure time is on the order of 20 minutes (for removal from the mold). The result is a tan, very hard product.
     
  18. Danger

    Danger 9,878
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    Man, I've learned a hell of a lot of new stuff in this thread. Keep it coming. :cool:
     
  19. dlgoff

    dlgoff 3,136
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    Why can't you use some type of mold-release? (spray-on, etc) If so then you can use an epoxy.
     
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