23 Nov
1999
23 Nov
'99
5 a.m.
The problem with ceramic materials (LIKE BEO) is that it fails in a
britle manner and quite a few miniscule specks of dust may become
airborne when it breaks (like a breaking glass window will often release
small and large fragments).
The main question is wheter you are prepared to take the risk,
for it takes a very tiny amount in your lungs to become a problem.
I Compare it to working with plutonium !!!
Alas, I only wanted to warn those on the list who were not yet informed
on the dangers of berylium-oxide (and metallic beryllium as I gathered
from subsequent treads).
Sipke de Wal
"He who liveth in a BEO house shall not throw stones"
Robert Garner wrote:
Sipke de Wal,
I passed your concern about Beryllium Oxide to someone here.
His response:
The only danger is as mentioned below, dust which does not
happen by accident. It is necessary to seriously grind or file the hard
material to create dust. As long as you do not try to machine it or
file it or break it up there is not problem.
So, assemblers should be warned not to mistreat it, breaking
grinding or filing it.
When I use it I also use thermal compound to make a good
thermal connection. This greasy substance also provides
a measure of added protection because if the BEO were
accidentally scratched or broken any small particles would
become mixed into this greasy compound and not become airborne.
It has the properties of:
1. a dielectric constant of about 6 for low capacitance
2. a very low thermal resistance for cooling
If there is great fear of using it alumina can be substituted:
1. dielectric constant of 10
2. low thermal resistance but not as good as BEO.
Ron Miller
> -----Original Message-----
> From: Sipke de Wal [SMTP:sipke@wxs.nl]
> Sent: Thursday, November 18, 1999 10:40 AM
> To: Discussion re-collecting of classic computers
> Subject: Re: E.U.N.U.C.H. (Cooling)
>
> Beware !!!!!!!!!!!!!!!!!!!
>
> Beryllium was mentioned here. Beryllium Oxide was used in the thermal
> conduction stuff HF-transistors decades ago, but this ceramic stuff can
> be quite lethal. If it breaks and you inhale a few microns of the dust
> there off, lungcancer can almost be guarantied within a decade !!!!
>
> Stay away from BEO !!!!!
>
> Sipke de Wal
>
>
>
> Hans Franke wrote:
> >
> > > At -100 Celsius: Al, 241; Cu, 420, Ag, 432. Interestingly enough, at
> these low
> > > temperatures Beryllium is pretty good at 367.
> >