Re: barium titanate doorknob caps/beryllium

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <uncadoc-at-juno-dot-com>

Hi all, I am sticking to the good old red clay from my backyard for
capacitor fusion experments. You folks got me scared now with this
Barium/Beryllium stuff.  But what differentiates good old red clay from
the barium stuff?  Is it written in 'stone' that a ceramic cap must be of
barium composition? Al.

On Sun, 15 Apr 2001 16:31:04 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: "Dr. Duncan Cadd by way of Terry Fritz 
> <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
> 
> Hi Ed, Jeff, All!
> 
> Happy Easter!
> 
> >> Keep in mind though that Barium anything (salts, oxides, nitrates
> etc) are
> >> very toxic.
> >> --jeff
> >
> > I think you men Beryllium rather than Barium.  As anyone who has
> ever
> >had a GI X-Ray exam, it is quite common to use Barium (something
> >soluble, don't know which salt) taken internally to define the
> >intestines.  Don't believe that would be done if it were toxic at
> all.
> >Ed
> 
> 
> Well actually Jeff is right and Ed is right.  Soluble barium salts 
> are
> toxic.  The stuff used in barium meals is a suspension of finely
> powdered barium sulphate (or possibly sulfate ;-) which is highly
> insoluble - just a quarter of a milligram dissolves per hundred ml 
> of
> water at 25C (it occurs naturally as barytes or "heavy spar") and
> therefore non-toxic because the barium is locked up by the sulphate
> ion and not accessible to the body.  Barium, when accessible to the
> body's chemistry, is toxic.  However . . .
> 
> Beryllium on the other hand (as found in beryllium copper alloys, 
> high
> power transistors etc as salts used for a heatsinking material 
> within
> the case) is in a different league.  It is _very_very_ toxic and is
> absorbed and accumulates easily in the body, so this may be an
> opportune moment to get on my chemistry soapbox and sound a general
> note of warning on beryllium.
> 
> You really should avoid machining, filing, heat-treating/welding etc
> beryllium alloys under home workshop conditions as the dust/vapour
> will do you a lot of serious no good. The pros can summon the aid of
> all manner of air monitoring, regular blood testing, containment and
> filtration mechanisms outside the range of an enthusiast's workshop.
> Never, never cut open a power transistor case.  Not all of them
> contain beryllium salts, but the risk isn't worth it.  If you have
> done any of these things, consider a blood screening seriously.
> 
> One of my ex-professional colleagues did a fair percentage of all 
> the
> world's known organometallic chemistry of beryllium.  His research 
> was
> officially stopped because of the toxicity problems - and this was 
> in
> the 1970s so you can guess how it must have been to attract 
> attention
> from officialdom back then.  (Back then, we were still boiling 
> benzene
> on the open bench.)  If you're into literature searching, look for
> papers by Prof. Coates of Durham uni, which might also bear the name
> Tom Caygill (my colleague, who was Prof. Coates' technician and who
> actually did most of the benchwork.)
> 
> Dunckx
> 
> 
> 

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