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I took apart a microwave, and when I saw the magnetron, I conviniently remembered that I had heard that magnetrons were dangerous. I decided to research this a bit further (I know, great timing) and I found that some magnetrons contains berilyum oxide, which is fatal if you breathe it in. I also read that it is dangerous in this way only if it's crushed, then inhaled. (It is also lethal if if you ingest it, but I'm not planning on doing that).

Since we stopped using that microwave, I haven't dropped it on the floor or anything like that, so does that mean that it is safe to handle? How could the magnetron become dangerous? What precautions should I take to make sure that I'm safe?

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  • \$\begingroup\$ Are you going to use it for a paper-weight or what? Other than a strong magnetic field it will harm nothing. Do NOT bust it open as there is a real glass tube inside the metal jacket. \$\endgroup\$ – Sparky256 Feb 3 '18 at 1:03
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    \$\begingroup\$ @Sparky256: commons.wikimedia.org/wiki/File:Magnetron3.jpg commons.wikimedia.org/wiki/File:Magnetron2.jpg \$\endgroup\$ – Janka Feb 3 '18 at 1:05
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    \$\begingroup\$ There are two dangerous things about a microwave oven: 1st, the microwaves. Do not turn it on without a proper shielding. 2nd, the high power high voltage. Do not turn it on without a proper, closed, grounded casing. \$\endgroup\$ – Janka Feb 3 '18 at 1:07
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    \$\begingroup\$ @skillz21 If your magnetron has a pink ring around it, then it contains beryllium oxide, which is extremely toxic if crushed. That's the only real danger if it isn't powered up. \$\endgroup\$ – Daffy Feb 3 '18 at 1:28
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    \$\begingroup\$ @skillz21 J. Raefield's answer covers that pretty well. If you're concerned about tossing it, call a recycling company and ask if they take microwave parts. Lots of Best Buy and Staples stores recycle. Look on greenergadgets.org and enter your zip code to get a lot of good places. \$\endgroup\$ – Daffy Feb 3 '18 at 4:30
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Some magnetrons use beryllium oxide as the "ceramic" looking insulators inside of the ring magnets on both the "Stem" and the "Antenna" ends. Reference the image below, the beryllium oxide parts are the pink items in the middle. They are totally inert if undisturbed.

enter image description here

Not all magnetrons use that for the insulators, but it's virtually impossible to tell if they did so you must assume they do. It has to get airborne to become dangerous. So just don't go crushing and snorting the ceramic dust and you will be fine. If you do happen to break one, don't use a vacuum cleaner, clean up with a damp rag and get ALL of the dust, then dispose of the rag while still wet by putting it in a plastic zip-lock bag.

I take apart magnetrons from old microwaves that I get for free and harvest the magnets, they are cool and powerful. I then put that center assembly into a thick plastic zip-lock bag before disposing of it.

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    \$\begingroup\$ So if it is not broken and I don't want to open it, and I haven't thrown it around, I'm good? \$\endgroup\$ – skillz21 Feb 3 '18 at 1:14
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As far as I can tell, the beryllium oxide insulator scare is nothing more than a myth. Probably originates from high power radar magnetrons, which do in fact use such BeO insulators sometimes. If you search for alumina TIG cups on Google you will find that they have exactly the same pink colour. That's no coincidence, chromium is added to alumina in manufacturing to improve its properties: http://www.iabrasive.com/articles/what-is-the-definition-of-pink-fused-alumina

Also thinking about it now, it wouldn't make any sense for manufacturers to use expensive and restricted beryllium insulators for a power dissipation of a few hundred watts, while alumina TIG welding cups have no problem being right next to a plasma heated by a few kilowatts.

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I find it pretty hard to believe your average microwave would be constructed with beryllium. Besides it being quite toxic and thus difficult to work with, it's also really expensive.

Maybe if you were dismantling a tokomak you would expect to find it...

Here is the sort of set-up you need to assemble your beryllium component safely: enter image description here

I really don't think a $20 microwave oven is going to go through that.

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