Can Metallic Plastic Used As A Heat Sink

Discussion in 'RC Cars, Boats and Planes' started by Innvotronics, Jul 15, 2017.

  1. Innvotronics
    Innvotronics Member
    I was wondering if the Metallic Plastic material could be used as a head sink for a video transmitter?
    Thank you.
  2. Shea_Design
    Shea_Design Well-Known Member
    I imagine the coefficient would be something just slightly above using HDPE. I'd say no. Perhaps find something stock or ripped out of some industrial liquidation facility. Got a flir cam? Maybe you can get all scientific and answer the question for everyone. I know the aluminum is expensive, perhaps a steel print of your design? -S
  3. Innvotronics
    Innvotronics Member
    Hi Shea,
    Thanks for responding, I am going to use a heat sink from McMaster with the Metallic Plastic as a frame to hold the heat sink and VTX. I will let you know how that goes.
    Thanks again.
  4. stonysmith
    stonysmith Well-Known Member Moderator
    On the materials page, it says "Metallic Plastic is heatproof to 78C / 172F degrees."

    The material is mostly Nylon, so objects made from it will act more as an insulator than a radiator.
  5. Innvotronics
    Innvotronics Member
    Hi Stonysmith, thank you for your input, makes sense, I appreciate it.

  6. MrNibbles
    MrNibbles Well-Known Member
    The answer depends on how much heat you need to dissipate and if you can design something that has a low enough thermal resistance in order to limit the temperature rise in your active device relative to the ambient air temperature. The main problem is knowing what the thermal conductivity is of the basic material, and then being able to calculate the thermal resistance to ambient air for a specific shape geometry and orientation, most likely using some kind of finite element analysis program. There is the slight benefit of having aluminum powder in the metallic plastic so I would expect the thermal conductivity to be slightly better than the strong and flexible materials, but obviously worse than the printed aluminum material I'd guess by at least a factor of 10. (Perhaps using aluminim nitride powder would give another tiny boost over aluminum powder.)

    Practically speaking the answer would likely be no for anything dissipating more than a small fraction of a watt, and if the material is more of a thermal insulator than air then it could make things worse. However it is an interesting problem, probably something worthy of trying.

    Anyone wanting to try this as a science fair experiment could use something like a power resistor in a TO-220 package mounted to the heat sink with device temperature measured using a thermocouple. Vary the power dissipated in the resistor, measure the corresponding device temperature rise, and calculate the thermal resistance. Adding a small dab of thermal grease between the device and the heat sink and some air flow from a fan wouldn't hurt and it's important to have the mating surface of the heat sink be as flat as possible.
  7. Innvotronics
    Innvotronics Member
    Hi MrNibbles, (I like your name ;))
    Thank you for the well thought out answer and suggestions as to how to determine the effectiveness of the material in question. I really appreciate it.

  8. mkroeker
    mkroeker Well-Known Member
    Thermal conductivity of EOS "alumide" is 0.5 to 0.8 W/mK according to data available on the 'net. If wikipedia is to be trusted, this puts it in the same ballpark as sand, glass or brick but a bit better than pure nylon (0.25...0.35). For comparison, aluminum alloys range from about 75 to 230, copper goes to 400 W/mK.