Thermal Grease

[Bill Fuqua]

I seem to remember that years ago there were warnings about contact with
the white grease. Remember many medications in the 1950s had mercury in
them. And watches had radium dials and remember the shoe stores with the
fluoroscopes? There was a time before people really cared about these
things. I remember reading soldering tip in one of the ham magazines. It
suggested holding the solder in your mouth when a third hand was needed.
Most of the inexpensive radios had 110 VAC on their chassis or common. Many
of the transmitter projects had exposed high voltage.

All I am saying is that it is possible that someone did produce a produce
with BeO in it taking into account the concerns those days. No products in
the past 30 or maybe 40 years surely have had BeO in powder form in them.

73
Bill wa4lav


At 11:44 PM 11/3/2004 -0500, J. Forster wrote:
>It is possible that at one time BeO was used in grease, but I've never
>seen it and
>I've been using the stuff since 1963. I very much doubt it's in commercial use
>anymore. In the late 60s, I was using BeO washers on TO-3 transistors.
>
>FWIW,
>-John
>
>
>Garey Barrell wrote:
>
> > Wes -
> >
> > That makes me feel better.   I thought I remembered beryllium oxide
> > grease.  NASA certainly was well above us "mere mortals!"   At least in
> > the 60's when I was there...
> >
> > Garey - K4OAH
> >
> > W. Kranitz wrote:
> >
> > >
> > > The "new" style white silicon grease is called "Type Z9"
> > > Silicon Heat Sink Compound. Some special application versions
> > > of this compound used beryllium oxide, but these were not available
> > > to us mear mortals. Most common versions use aluminum or zinc
> > > compounds. Some of the newer types use Micronized Silver (eg, DYNEX
> > > Silver Thermal Compound). These are used for the high heat transfer
> > > needed for modern microprocessors.
> > >
> > >
> > > Garey Barrell wrote:
> > >
> > >> 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
>
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