"Heat Sink Putty" ?

Discussion in 'Electronic Repair' started by (PeteCresswell), Mar 2, 2008.

  1. Any such thing?

    I'll have a little bridge rectifier and voltage regulator serving
    a bicycle hub alternator (6v 4w) and want to use the bike frame
    as the heat sink.

    My thought was that, if there's such a thing as heat-conductive
    putty, I'd just embed the two components in some of it and stick
    it to a frame tube.
    --
    PeteCresswell
    (PeteCresswell), Mar 2, 2008
    #1
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  2. I've never heard of putty. Silicone grease is common, of course.
    William Sommerwerck, Mar 3, 2008
    #2
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  3. (PeteCresswell)

    Eeyore Guest

    "(PeteCresswell)" wrote:

    > Any such thing?
    >
    > I'll have a little bridge rectifier and voltage regulator serving
    > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > as the heat sink.
    >
    > My thought was that, if there's such a thing as heat-conductive
    > putty, I'd just embed the two components in some of it and stick
    > it to a frame tube.


    Aluminium powder mixed with epoxy might work.

    Graham
    Eeyore, Mar 3, 2008
    #3
  4. "(PeteCresswell)" <> wrote in message
    news:...
    > Any such thing?
    >
    > I'll have a little bridge rectifier and voltage regulator serving
    > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > as the heat sink.
    >
    > My thought was that, if there's such a thing as heat-conductive
    > putty, I'd just embed the two components in some of it and stick
    > it to a frame tube.


    **Do you need heat sinking? 4 Watts is not much power. You could use a 6 Amp
    bridge, which can dissipate quite a bit of power, before requiring any heat
    sink. If you do need it, then use silicon glue (the stuff used for
    guttering, kitchens, bathrooms, etc). It remains flexible and will transfer
    reasonable heat to the frame. I seriously doubt that you need it though.

    Trevor Wilson
    Trevor Wilson, Mar 3, 2008
    #4
  5. (PeteCresswell)

    Smitty Two Guest

    In article <>,
    Eeyore <> wrote:

    > "(PeteCresswell)" wrote:
    >
    > > Any such thing?
    > >
    > > I'll have a little bridge rectifier and voltage regulator serving
    > > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > > as the heat sink.
    > >
    > > My thought was that, if there's such a thing as heat-conductive
    > > putty, I'd just embed the two components in some of it and stick
    > > it to a frame tube.

    >
    > Aluminium powder mixed with epoxy might work.
    >
    > Graham


    Don't they make thermally conductive epoxy? OP might not want anything
    electrically conductive.
    Smitty Two, Mar 3, 2008
    #5
  6. (PeteCresswell)

    GregS Guest

    In article <>, "(PeteCresswell)" <> wrote:
    >Any such thing?
    >
    >I'll have a little bridge rectifier and voltage regulator serving
    >a bicycle hub alternator (6v 4w) and want to use the bike frame
    >as the heat sink.
    >
    >My thought was that, if there's such a thing as heat-conductive
    >putty, I'd just embed the two components in some of it and stick
    >it to a frame tube.


    Thermal epoxy is better than regular epoxy but the conductivity
    is very poor compared to copper, and copper is poor compared to diamond.
    Might try the suggestion of adding metal filings to regular epoxy putty.
    Thermal epoxy is not really putty.

    greg
    GregS, Mar 3, 2008
    #6
  7. (PeteCresswell)

    GregS Guest

    In article <fqgvvv$r1s$>, (GregS) wrote:
    >In article <>, "(PeteCresswell)"
    > <> wrote:
    >>Any such thing?
    >>
    >>I'll have a little bridge rectifier and voltage regulator serving
    >>a bicycle hub alternator (6v 4w) and want to use the bike frame
    >>as the heat sink.
    >>
    >>My thought was that, if there's such a thing as heat-conductive
    >>putty, I'd just embed the two components in some of it and stick
    >>it to a frame tube.

    >
    >Thermal epoxy is better than regular epoxy but the conductivity
    >is very poor compared to copper, and copper is poor compared to diamond.
    >Might try the suggestion of adding metal filings to regular epoxy putty.
    >Thermal epoxy is not really putty.
    >


    The thermal epoxy I am currently using on a project is a lot thicker than
    regular epoxy. Its Omega Bond 101.

    greg
    GregS, Mar 3, 2008
    #7
  8. (PeteCresswell)

    PeterD Guest

    On Sun, 02 Mar 2008 18:36:38 -0800, Smitty Two
    <> wrote:

    >In article <>,
    > Eeyore <> wrote:
    >
    >> "(PeteCresswell)" wrote:
    >>
    >> > Any such thing?
    >> >
    >> > I'll have a little bridge rectifier and voltage regulator serving
    >> > a bicycle hub alternator (6v 4w) and want to use the bike frame
    >> > as the heat sink.
    >> >
    >> > My thought was that, if there's such a thing as heat-conductive
    >> > putty, I'd just embed the two components in some of it and stick
    >> > it to a frame tube.

    >>
    >> Aluminium powder mixed with epoxy might work.
    >>
    >> Graham

    >
    >Don't they make thermally conductive epoxy? OP might not want anything
    >electrically conductive.


    Then use zinc oxide with epoxy, that should not be conductive... But
    regardless, nothing will work very well, IMHO...
    PeterD, Mar 3, 2008
    #8
  9. (PeteCresswell)

    GregS Guest

    In article <>, PeterD <> wrote:
    >On Sun, 02 Mar 2008 18:36:38 -0800, Smitty Two
    ><> wrote:
    >
    >>In article <>,
    >> Eeyore <> wrote:
    >>
    >>> "(PeteCresswell)" wrote:
    >>>
    >>> > Any such thing?
    >>> >
    >>> > I'll have a little bridge rectifier and voltage regulator serving
    >>> > a bicycle hub alternator (6v 4w) and want to use the bike frame
    >>> > as the heat sink.
    >>> >
    >>> > My thought was that, if there's such a thing as heat-conductive
    >>> > putty, I'd just embed the two components in some of it and stick
    >>> > it to a frame tube.
    >>>
    >>> Aluminium powder mixed with epoxy might work.
    >>>
    >>> Graham

    >>
    >>Don't they make thermally conductive epoxy? OP might not want anything
    >>electrically conductive.

    >
    >Then use zinc oxide with epoxy, that should not be conductive... But
    >regardless, nothing will work very well, IMHO...


    Seems like there are atachments to the frame for accesories, and if they
    are aluminum, it will make a great way to do it. Curved surface aluminum
    block.

    greg
    GregS, Mar 3, 2008
    #9
  10. (PeteCresswell)

    Jim Yanik Guest

    (GregS) wrote in
    news:fqgvvv$r1s$:

    > In article <>,
    > "(PeteCresswell)" <> wrote:
    >>Any such thing?
    >>
    >>I'll have a little bridge rectifier and voltage regulator serving
    >>a bicycle hub alternator (6v 4w) and want to use the bike frame
    >>as the heat sink.
    >>
    >>My thought was that, if there's such a thing as heat-conductive
    >>putty, I'd just embed the two components in some of it and stick
    >>it to a frame tube.

    >
    > Thermal epoxy is better than regular epoxy but the conductivity
    > is very poor compared to copper, and copper is poor compared to
    > diamond. Might try the suggestion of adding metal filings to regular
    > epoxy putty. Thermal epoxy is not really putty.
    >
    > greg
    >


    whatcha need is diamond-filled epoxy..... :cool:

    you can buy very finely powdered copper at craft stores.
    by the time you get enough copper or other filler mixed in the epoxy,it IS
    the consistency of putty..... ;-)

    better to machine an aluminum mount to mate closely with the bike tubing
    and coat it with thermal paste,mount the circuit to the Al. plate. with
    thermal paste.

    Or use a switcher-type regulator for lower heat dissipation.

    --
    Jim Yanik
    jyanik
    at
    kua.net
    Jim Yanik, Mar 3, 2008
    #10
  11. (PeteCresswell)

    Jim Yanik Guest

    (GregS) wrote in
    news:fqgvvv$r1s$:

    > In article <>,
    > "(PeteCresswell)" <> wrote:
    >>Any such thing?
    >>
    >>I'll have a little bridge rectifier and voltage regulator serving
    >>a bicycle hub alternator (6v 4w) and want to use the bike frame
    >>as the heat sink.
    >>
    >>My thought was that, if there's such a thing as heat-conductive
    >>putty, I'd just embed the two components in some of it and stick
    >>it to a frame tube.

    >
    > Thermal epoxy is better than regular epoxy but the conductivity
    > is very poor compared to copper, and copper is poor compared to
    > diamond. Might try the suggestion of adding metal filings to regular
    > epoxy putty. Thermal epoxy is not really putty.
    >
    > greg


    there's a silver-filled thermal epoxy,Arctic Silver.

    http://www.arcticsilver.com/instructions.htm

    http://www.newegg.com/Product/Product.aspx?Item=N82E16835100005

    --
    Jim Yanik
    jyanik
    at
    kua.net
    Jim Yanik, Mar 3, 2008
    #11
  12. (PeteCresswell)

    whit3rd Guest

    On Mar 2, 3:46 pm, "(PeteCresswell)" <> wrote:


    > I'll have a little bridge rectifier and voltage regulator serving
    > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > as the heat sink.    


    If there's a brazed boss in some convenient spot, you can screw a
    block of aluminum to that (or even a 1" square plate). The rectifier
    won't need conduction cooling at these power levels, so it's just
    the (three terminal TO-220?) regulator or pass transistor that gets
    warm.

    Generator mount bracket or headlamp bracket are good candidates.
    If they get warm, it sinks to the frame quick enough.
    whit3rd, Mar 3, 2008
    #12
  13. (PeteCresswell)

    Guest

    , Mar 3, 2008
    #13
  14. (PeteCresswell)

    Eeyore Guest

    Smitty Two wrote:

    > Eeyore <> wrote:
    > > "(PeteCresswell)" wrote:
    > >
    > > > Any such thing?
    > > >
    > > > I'll have a little bridge rectifier and voltage regulator serving
    > > > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > > > as the heat sink.
    > > >
    > > > My thought was that, if there's such a thing as heat-conductive
    > > > putty, I'd just embed the two components in some of it and stick
    > > > it to a frame tube.

    > >
    > > Aluminium powder mixed with epoxy might work.

    >
    > Don't they make thermally conductive epoxy? OP might not want anything
    > electrically conductive.


    Bridge tectifiers usually have isolated cases anyway.

    Trevor's idea is good though. Use a larger bridge than actually needed
    (they're not expensive) and it'll happilly dissipate the heat without
    additional cooling.

    Graham
    Eeyore, Mar 4, 2008
    #14
  15. (PeteCresswell)

    Eeyore Guest

    Jim Yanik wrote:

    > Or use a switcher-type regulator for lower heat dissipation.


    That's a particularly good idea.

    Graham
    Eeyore, Mar 4, 2008
    #15
  16. Per Trevor Wilson:
    >**Do you need heat sinking? 4 Watts is not much power. You could use a 6 Amp
    >bridge, which can dissipate quite a bit of power, before requiring any heat
    >sink.


    I just checked the specs on the one I ordered. 25 amps/50v.

    Sounds like my dinky little hub alternator will barely warm it
    up. So much for the heat sink requirement....
    --
    PeteCresswell
    (PeteCresswell), Mar 4, 2008
    #16
  17. (PeteCresswell)

    Guest

    Heat sink putty is old hat.It's been around for many years.
    cuhulin
    , Mar 4, 2008
    #17
  18. (PeteCresswell)

    Jimmie D Guest

    "(PeteCresswell)" <> wrote in message
    news:...
    > Any such thing?
    >
    > I'll have a little bridge rectifier and voltage regulator serving
    > a bicycle hub alternator (6v 4w) and want to use the bike frame
    > as the heat sink.
    >
    > My thought was that, if there's such a thing as heat-conductive
    > putty, I'd just embed the two components in some of it and stick
    > it to a frame tube.
    > --
    > PeteCresswell


    There is an epoxy but it doesnt work like you want.It must be applied thinly
    and used to conduct heat to a heatsink.
    Just get a really big rectifier. I have a 5 amp power supply that uses a 20
    amp bridge and its bolted to a piece of wood.

    Jimmie
    Jimmie D, Mar 7, 2008
    #18
  19. Per Jimmie D:
    >Just get a really big rectifier. I have a 5 amp power supply that uses a 20
    >amp bridge and its bolted to a piece of wood.


    That's what I (inadvertently) did. 25 amp/50 volt to handle
    about 1 amp/20 volts max.
    --
    PeteCresswell
    (PeteCresswell), Mar 7, 2008
    #19
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