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'[OT] Question - Berylium in Microwave oven magnetr'
2000\03\14@050556 by Russell McMahon

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Does anyone know if  Beryllium (or crushed PICs :-)) is ever used in the
ceramic insulators in microwave oven magnetrons?
They warn against high voltage and microwave radiation and don;'t mention
beryllium so one would HOPE that they haven't resorted to such materials.
But ....
Not a material I would want to encounter accidentally.

TIA



     Russell McMahon
_____________________________

>From other worlds - http://www.easttimor.com
                               http://www.sudan.com

What can one man* do?
Help the hungry at no cost to yourself!
at  http://www.thehungersite.com/

(* - or woman, child or internet enabled intelligent entity :-))

2000\03\14@064929 by Pavel Kristek

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I think not because berillium ceramics is toxic

-----Original Message-----
From: Russell McMahon [spam_OUTapptechTakeThisOuTspamCLEAR.NET.NZ]
Sent: Tuesday, March 14, 2000 5:18 AM
To: .....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU
Subject: [OT] Question - Berylium in Microwave oven magnetrons?


Does anyone know if  Beryllium (or crushed PICs :-)) is ever used in the
ceramic insulators in microwave oven magnetrons?
They warn against high voltage and microwave radiation and don;'t mention
beryllium so one would HOPE that they haven't resorted to such materials.
But ....
Not a material I would want to encounter accidentally.

TIA



     Russell McMahon
_____________________________

>From other worlds - http://www.easttimor.com
                               http://www.sudan.com

What can one man* do?
Help the hungry at no cost to yourself!
at  http://www.thehungersite.com/

(* - or woman, child or internet enabled intelligent entity :-))

2000\03\14@070211 by Alan Pearce

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Items that contain BeO that I have seen have a note to this effect on the
external label. I cannot think of a reason why any item in a microwave oven
would contain BeO.

There is only two uses I am aware of for it.

1. Heat transfer capability in insulation washers. It has a lower thermal
resistance per unit thickness than Aluminium Oxide. It used to be used in RF
transistors for this reason (the early VHF high power types with the white disc
washers).

2. It was used in early fluorescent tubes as one of the powders to coat the
inside of the tube. Not used for many years because of its toxicity and the ease
of breakage for these tubes.

2000\03\14@090624 by Andrew Kunz

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face
It's also used extensively in the model boat propellers I use to provide light
weight with strength, as part of a BeCu alloy.

So if someday I'm not here, you might guess why.

Andy











Alan Pearce <A.B.PearcespamKILLspamRL.AC.UK> on 03/14/2000 07:00:07 AM

Please respond to pic microcontroller discussion list <.....PICLISTKILLspamspam.....MITVMA.MIT.EDU>








To:      EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU

cc:      (bcc: Andrew Kunz/TDI_NOTES)



Subject: Re: [OT] Question - Berylium in Microwave oven
         magnetrons?








Items that contain BeO that I have seen have a note to this effect on the
external label. I cannot think of a reason why any item in a microwave oven
would contain BeO.

There is only two uses I am aware of for it.

1. Heat transfer capability in insulation washers. It has a lower thermal
resistance per unit thickness than Aluminium Oxide. It used to be used in RF
transistors for this reason (the early VHF high power types with the white disc
washers).

2. It was used in early fluorescent tubes as one of the powders to coat the
inside of the tube. Not used for many years because of its toxicity and the ease
of breakage for these tubes.

2000\03\14@100631 by Jim Hartmann
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face
here's some info - http://www.nsc.org/ehc/ew/chems/berylliu.htm

2000\03\14@194917 by Russell McMahon

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>Items that contain BeO that I have seen have a note to this effect on the
>external label. I cannot think of a reason why any item in a microwave oven
>would contain BeO.


They appear to use a ceramic insulator between the Anode and the body. The
Anode is going to get rather hot given the power levels involved and they
will be aiming at best heat transfer here.


Uh Oh !!!!!!!!!!
The url that Jim Hratman provided -
   http://www.nsc.org/ehc/ew/chems/berylliu.htm
says
"Beryllium oxide is used to make specialty electrical and high-technology
ceramics, electronic heat sinks, electrical insulators,
MICROWAVE OVEN COMPONENTS" ,
gyroscopes, military vehicle armor, rocket nozzles, and laser structural
components. Beryllium alloys are used in electrical connectors and relays,
springs, precision instruments, aircraft engine parts, nonsparking tools,
submarine cable housings and pivots, wheels, and pinions.

RM

2000\03\14@222913 by Sean Breheny

face picon face
Russell,

What did you do? Did you crack one of these and are now worried about the
consquences? Or, is this just something you want to know for the future?

Sean

At 12:19 PM 3/15/00 +1300, you wrote:
{Quote hidden}

| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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2000\03\14@225507 by Brian Kraut

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I know that a lot of magnetrons for marine radars have Be and are not always
markes as containing it directly on the magnetron.  There is usually a
marking on the box.

----- Original Message -----
From: Pavel Kristek <@spam@KristekKILLspamspamINTERBELL.CZ>
To: <KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU>
Sent: Tuesday, March 14, 2000 6:48 AM
Subject: Re: [OT] Question - Berylium in Microwave oven magnetrons?


> I think not because berillium ceramics is toxic
>
> {Original Message removed}

2000\03\15@012237 by Graeme Zimmer

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face
> I cannot think of a reason why any item in a microwave oven
> would contain BeO.

Many high power vacuum tubes use disks of BeO as the insulating layers
between the metal body parts...

I dunno if any magnetrons is it, but it would not be unlikely.

................... Zim

2000\03\15@124444 by Alice Campbell

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face
So, Russell,

were you melting metal in the microwave and it blew?  if you're
worried about contamination, the dust is the bad stuff.  DO NOT
BREATHE IT.  otherwise, its not so bad.  Use a solution of water
and detergent, simple green is nice but i dont know if they have it
in NZ--this has a wetting agent that helps wet the dust so it doesnt
go into the air.  Drop in two drops of water-color pigment, or food
color or ink.... Mist-spray this solution into the cavity of the
microwave, the workbench, or anything you have touched, including
the light switches etc, to stabilize the dust, but dont get it all
runny.  Now get some disposable gloves,  dry paper towels, and
clean up the mess and put it in a double plastic trash bag.  the
food coloring is there to tell you when its clean, and where it is.
although one exposure probably wont kill you, chronic exposure is
the problem.

alice

so did it melt?

> here's some info - http://www.nsc.org/ehc/ew/chems/berylliu.htm

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