talk to me about potting, heat sinking / potting compound that conducts heat?

[jontawn]

As per the title really!!!

Any info on home made heat sinks, how you made them, why you use XYZ material as the heat sink, if you use a potting compound, which one and does it have thermal properties for removing the heat from the board, and into the heat sink?

regards
Jonathan

 

[CampingLED]

As per the title really!!!

Any info on home made heat sinks, how you made them, why you use XYZ material as the heat sink, if you use a potting compound, which one and does it have thermal properties for removing the heat from the board, and into the heat sink?

regards
Jonathan

"talk to me" is not a nice way to start a new thread. Have you searched some existing threads? This forum contains an overload of info.

 

[jontawn]

CampingLED; Firstly, please accept my apologies if my wording came accross as abrupt or somewhat curt, it certainly was not meant in that sense.
However, where I live (Sheffield, England) saying such a phrase is perfectly acceptable and is generally considered quite friendly! (well, at the least, within the circles I mix)

But Yes, If anyone could offer further enlightenment (pun not intended) on this subject and comments regarding their own personal choices of heatsinking and the construction, it would be most helpful. - Yes, I have searched and can see what appears to be plenty of lathed devices bought off of other forum members.

regards
Jonathan

 

[LukeA]

Fujik

 

[CampingLED]

:welcome:

Personally I also use the thermal glue that LukeA referred to. You can also use the thermal paste, but then you need to drill holes and use screws to affix the LED/Star to the heat sink. The thermal glue also isolate the LED/Star from the heat sink.

This link to a site of a former CPF member should contain most of the info that you need/want to know about heat sinks.

 

[Steve K]

Regarding potting: there are potting materials that are modestly thermally conductive. The one that I've used in the past (at work) contained aluminum oxide particles in the potting. It resulted in a very hard potting, which made it very resistant to damage from impacts and such.

Potting is not easy to use, however. There are a lot of little issues that can cause trouble. For hard potting, the thermal coefficient of expansion is usually different from the circuit board, and this can cause damage to the electronics.

A couple of the potting companies are Emerson & Cuming (http://www.emersoncuming.com/), Dow Corning, GE, or Loctite (search on "Loctite potting and encapsulating").

One of the Emerson Cuming products is this:
http://www.emersoncuming.com/other/1495k.pdf

For the best heat transfer, there's nothing like a direct metallic path from the LED package to the ambient air. A solid piece of aluminum is the typical solution. Heat sink grease or adhesive is helpful at minimizing the thermal resistance between bodies. To maximize the heat transfer from the heatsink to the ambient air, maximize the surface area of the heatsink without making the aluminum too thin for the heat to easily flow through it.

that's the quick lesson. What are the specifics of what you are trying to do??

cheers,
Steve K.

 

[jontawn]

Hi there, my intention was to mount a SSC P7 into a cateye abs30 bike light, and wanted some advice on potting the driver circuit if I choose to mount it within the lamp enclosure. I was thinking of using either copper or alu to make the heatsink. Then mount that into the housing with interference fit and mechanical fixngs along with heatsink compound to the cateye housing.

Thankyou for your replies so far!!!!!

Jonathan