Microspheres and syntactic foam

Discussion in 'Materials' started by Nate57, Jul 10, 2013.

  1. Nate57
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    Nate57 Junior Member

    I'm hoping to make my own syntactic foam for use in buoyancy floats on a deepwater (3000 meters) research net. My thoughts were to winnow microspheres in water to assure they all float, dry them, mix them with epoxy resin and pour them into a mold. Any feedback on this plan would be appreciated. Specific questions would be what might be the highest ratio of microspheres to resin (by volume) I might get away with (without voids) and should I expect problems with an exothermic reaction in my mold?
    Any thoughts?
     
  2. TeddyDiver
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    TeddyDiver Gollywobbler

    Sounds a bit weird solution. Pressure in depth is against any foam (gas filled) floats. How much buoyancy you are looking after? Better to consider lighter than water liquids IMO
     
  3. Nate57
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    Nate57 Junior Member

    Well syntactic foam is used for buoyancy in other deepwater endeavors such as AUV's. Net floats made of it are just very expensive. Glass balls remain one of the best for high pressure use and glass microspheres even more so. Perhaps there's more to making syntactic foam than I realize.
    I hadn't considered lighter than water liquids but believe limitations of space would preclude them for my use.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Might be an idea to find out why they are so expensive, by talking to the maker.
     
  5. PAR
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    PAR Yacht Designer/Builder

    Syntactic foam is expensive to make in a factory, for the same reasons it'll be expensive to make in your garage. You seem to have a good grasp on the process, so sourcing the materials for best pricing, seems the only positive options.
     
  6. SamSam
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    SamSam Senior Member

    Apparently they have different microspheres for different uses, so that might be why the price is high.
    http://etd.lsu.edu/docs/available/etd-07142005-151356/unrestricted/Maharsia_dis.pdf

    How many of these floats do you need and what size and shape are they?

    If there are problems with exotherm, you can make the floats in stages allowing excess heat to dissipate for an hour or so while still getting a good bond between pours.

    How much pressure is there at 3000 meters?
     
  7. PAR
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    PAR Yacht Designer/Builder

    About 4,400 PSI is my quick head math guess (14.7 PSI for every 10 meters). Yes, mixing diameters and using the toughest little balls you can find makes a lot of sense.
     
  8. Nate57
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    Nate57 Junior Member

    Thanks for all the input. If you guys don't think I'm too far off base it must be feasible. I've got a lot more study and sourcing to do. And then the long trip out to 3000 meters to test a prototype. Arrgh!
     

  9. Mr Efficiency
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    Mr Efficiency Senior Member

    What happens to light-weight wood in such pressures ? Extreme compaction ?
     
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