"TOM WALKER" bravely wrote to "JEAN PARROT" (25 Mar 05  07:05:00)
 --- on the heady topic of "Adhesives for Testing"

 JP>        As you say, too much of a good thing does not make it better.
 JP>  The amount of goo required is minimal as the "acceptor" on the fan
 JP>  block is flat on the CPU body and tight too.

 TW> The thermal goo is really only to fill in the imperfection and
 TW> scratches o nthe surfaced. Solid contact is the best heat tranmsfer
 TW> way. The thin film of go ois only to eliminate the smal lAir cavities
 TW> whics conduct very poorly.
 TW> I suppose in Theory a Lapped surface is best. But that is not
 TW> practical on the CPU itslef becuase it is so easy to damage a
 TW> possabibly expensive CPU..

Even two absolutely flat surfaces don't have a perfect contact because
at the molecular level there are peaks and valleys. Plus there is
uncertainty about where the electrons are at any one time and it is
these that are involved in the mechanism of thermal exchange. The
thermal goop fills the space between molecule valleys better and
supplies more electrons which in turn increases the thermal
conductivity. As a result a good thermal compound will almost double
the thermal conduction of even very flat highly polished surfaces.

 M*i*k*e

... Of course I'm on topic... Which echo is this anyway?
--- Blue Wave/DOS v2.30