"Lab1" .@... wrote in message
...
On 1/19/2011 2:25 PM, Meat Plow wrote:

Great dollops of that white goo between metal to metal thermally
conductive surfaces.

Overuse of that stuff is worse for thermal conductivity than none at all.
I've clean up gobs of it since they started using it decades ago.

This is something I'm currently wondering about. I have a fridge-like
thermo-electric cooler than has two sections, top and bottom, with
different temperatures. The top suddenly stopped getting cool at all, so I
took it apart to figure out why. The fans and voltages were all there so I
broke down the heat sinks on the bad one to get to the Peltier device.
With it isolated, I powered it up briefly and much to my surprise the
Peltier device got hot real quickly with the opposite side getting cooler.
So the device works, it has to be something with the heat sinks?
They did use white goop on both sides, but very little and it was already
dried. The heat sinks are milled flat where they make contact with the
Peltier device, so my thinking is they need new goop.
Looking around I found that Star heat sink compound is about the best you
can get, so I ordered some. It just arrived the other day so I'm planning
to clean up the old goop, put on some new goop and hope for the best. I
don't think too much would be an issue in this case, I want it as cold as
possible.





--
-Scott



Too much of the stuff will be a problem whether you are trying to heat or
cool. I have some major doubts that a thin coating of that stuff would be
enough to make any major difference in the performance of peteler junction.
Now on the other hand, if the heatsink is loose... That could give you some
real issues.