Thermal Grease

[Garey Barrell]

Jerry -

There are at least two types that I am aware of.

The "old" style was clear silicone grease.

The "new" style is white silicone grease loaded with beryllium oxide.

Both work pretty much the same, the purpose being to fill any  TINY  air
pockets trapped between what ideally would be two "perfectly" flat
surfaces.  The idea is that the grease is a better at heat transfer than
air.  It is NOT a better conductor than metal, so a big blob of grease
isn't going to transfer much heat between two surfaces that don't touch.!

Proper use calls for only a VERY thin smear.  Most people use WAY too
much, which of course gets squeezed out when the two pieces are clamped
together.

By the way, beryllium oxide DUST is considered very toxic if inhaled, so
I guess you wouldn't want to eat the stuff!

73, Garey - K4OAH
Atlanta


Jerry Seligman wrote:

> A question came up in discussions with friends. Is the thermal grease
> used on power transistors, the same as the type used in computers
> (for example on the CPU chip)?
> Jerry W7BUN
>

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