Advice on making a small moulded part

Discussion in 'Materials' started by alyne, Oct 13, 2007.

  1. alyne
    Joined: Aug 2003
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    alyne Junior Member

    Hi all

    I hope you don't mind me asking this question as this time it is not to do with boats however I could really do with some advice on a small project I am doing.

    Basically I want to cast a solid conical shape about the size of a coffe mug. No problem making the mould but my question is what type of resin / material would be the best to use. As this is a solid shape I would just poor in the resin into the mould but my concern is the amount of heat I might generate. Also being on a small budget, and I might have to make several castings, so using epoxy resin might be quite expensive


    So really my question is, what moulding material could I use apart from expensive epoxy resin? or if that is indeed the only solution am I better off with a slow cure to lessen heat generation?

    I should add that I need to drill the moulded part so using plaster type moulding material wouldn't be any good

    Thanks in advance
    Andy Lyne
     
  2. starktr
    Joined: Sep 2007
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    starktr Retired

    Clean dry sand mixed into the catalyzed polyester resin provides a cheap heat sink. Mix in a little milled glass fiber before the sand if you want more strength. Best invest in a carbide masonry bit for drilling.
     
  3. alyne
    Joined: Aug 2003
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    alyne Junior Member

    Thank you for your post. I was thinking, what about using some of those plastic granules they use to manufacture plastic kayaks in a rotomould oven, if I could get some of that I guess I could just heat some up in a pan and pour it in?
     
  4. SamSam
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    SamSam Senior Member

    You don't say what you are making or what they're for. Big lumps of polyester shrink and crack, and sometimes start on fire. Check out 'casting resin' on the net or in an art supply store.
     
  5. alan white
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    alan white Senior Member

    If you coat the interior of the mold 1/4" thick with polyester (bondo will do, and it's cheap and found at the auto parts store), then add more layers once cured, and more until solid, you will have your plastic cone.
    What is this to be used for?
     
  6. alan white
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    alan white Senior Member

    That would work, though I don't know how accurate this thing needs to be. Also, polypropelene is softer than other plastics. Epoxy or straight polyester resins are pretty hard in comparison.
     
  7. alyne
    Joined: Aug 2003
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    alyne Junior Member

    Thanks for the advice, as the part doesn't have to be too strong, I shan't use epoxy or polyester, I think you have given me plenty of options to try.

    As for what I'm making its just a mad idea I have for building a type of tent for my kids..... I'm one of those people that just has to be making something....it keeps me out of mischief :)

    Anyway all your advice is much appreciated

    Regards
    Andy
     
  8. alan white
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    alan white Senior Member

    Your kids are obviously very small. If I'd known, I'd have suggested a funnel, which you could cut a door in. Anyway, good luck, and remember to keep a close eye on the campers---- what with racoons and squirrells about.

    Alan
     
  9. SamSam
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    SamSam Senior Member

  10. alan white
    Joined: Mar 2007
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    alan white Senior Member

    Being a small kid advovate myself, I'm constantly thinking up new and safe ways to protect children under four inches tall. Now I can tell people to avoid Germany if their kids are really miniscule.
    I'm pleased, as well, that others are working on "safe houses" for super small tykes. I'm doubly pleased that boatbuilding technology is becoming a part of the solution.

    Alan White
    MicroKid International
    Raccoon Protection division
     

  11. alyne
    Joined: Aug 2003
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    alyne Junior Member

    OK, I might as well tell you exactly what I am working on. I was being a bit vague as once my idea is out I can see the big players jumping on it.

    I am developing a tent for children less than 4 inches high. But it's just not just any tent, due to the inherrent strength properties of a conical shape it also doubles as a bomb shelter. But here is the really cleaver bit, turn it upside down, put a sail on it and voila you have a boat!

    To market the idea I was thinking of building a 10 foot version and doing this:

    http://www.aroundinten.com/

    My only concern now the cat is out of the bag that some of you clever designers are going to steal my conical boat design concept :)

    All the best
    Andy (mad scientist)
     
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