On Thu, 4 Jul 2002, Roman Black wrote:

>Is heatsink flatness really that critical?
>I thought the heatsink compound is denser than
>aluminium anyway so provided there is heaps of
>goop on the part it won't matter if the 'sink
>is flat or not?

The flatness has to do woth breaking the chips on the carrier being
mounted, and not with heat. Heatsink compound is denser than aluminium in
the weight sense (maybe) but it is more ductile. So it fills the voids
which is what it is supposed to do.

>I've used some real rough bits of alloy for 'sinks
>in the past, with lots of goop. :o)

The goop is not snake oil. If you want real good conductivity you want the
sealant to be thin. This means flat surfaces. The copper flashing shim I
proposed usually solves the problem of not so perfect surface finish
assuming it can be tightened well.

Peter

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