There are portions of the magnetron that look like ceramic insulators. That's the BeO. It's typically the portion that's under the emitter tip and it goes into the finned body of the unit. In this picture. the reddish-brown material that looks like burnt ceramic would be the BeO.
You could use BeO for heat sinks, but it's toxicity and expense makes that prohibitive. It's easier to use copper or aluminum, which have relatively few side effects.
Ok. I currently don't have any used microwaves to take apart but next time I do I'll look closely. Fortunately I did all this outdoors and only broke open a few emitters.
I carefully took the ends off a couple emitters to see inside as I was very curious as to the construction.
Many of the microwaves I see tossed to the curb in residential areas are not even in that bad of condition. Maybe a fuse out or something.
The smaller ones that don't have the plate with the cog on the bottom, those are the best plates to use for eating. The ones with the three lobed cog are no good since it high centers. It's a shame to toss them in the trash.
If you're not suffering from any respiratory problems, you probably didn't inhale any BeO dust (or enough to do any damage.)
Modern microwaves with electronic control boards use the absolute cheapest shit relays for power control that they can get their hand on. When I did appliance repair for a company that has a round logo, some of the newer boards (mid 90s) that Samsung provided were made with cheaper than chips relays. They were uncoated copper contacts and would just arc and burn closed or open, and you'd lose the device. No batch of these parts had the same name, everything from "Yung Reem" to "Bright Star" was stamped on them. We heard rumors that these things were made by whomever won the contract that month.
Funny story, my boss talked to the engineering staff at Appliance Park that approved these. They said "Well, we tested some relays and they worked fine!" Boss goes "Did you buy them from a commercial supply house?" Nope, they were samples from Samsung themselves, hand picked and massaged to work the best.
Hey, thanks for the assurances. After I found out about the beryllium and remembering the precautions we took at the processing factory I was a bit alarmed. I tossed all the emitters I had left, damn the copper and vowed to not open up any more until I had more information.
Yes, I noticed the cheap safety cutout switches and stuff. Those things are uber cheap made with the bare minimum of circuits needed. After I took one capacitor apart not knowing the composition of the coil I just noted how quickly it oxidized and tossed the rest as I had no plans for them. I saved out all the transformers because I wrongly believed the windings were copper but unfortunately, all I have checked had aluminum windings.
I needed the copper windings as I was searching for suitable sized copper wire to use in jewelry wire wrap.
The one thing that has irked me is that even after carefully straightening what copper wiring I did get from windings around little feroceramic devices there is a pesky varnish I have not found a solvent to clean it off. With the varnish I can not use an oxidizer to blacken the copper for jewelry. If you know how to easily dissolve the varnish on copper wires I would love to know and be very grateful as I've found no source online explaining this. To get the varnish off I have carefully heated coils over a gas burner and then sanded off the carbon and have just used fine grit to sand the wires.
I will say, the coils around an old picture tube from a cathode tube TV are excellent wires. The fine windings I discard as I have no smelter but the heavier windings from the tube are perfect size. Since I'm stocked up now I quit searching out microwaves and am now focused on processing the copper wires I have.
BTW, the new flat screen TV's have little of value in the way of wires or gold fingers.
I did manage to get an old plasma flat screen, very large and almost too heavy to carry. On disassembly I noted that the base was heavy steel for weight but inside were hundreds of connections with gold plated fingers. I saved all the fingers from the many circuit boards and found some interesting wires. I had about eight ounces of fingers, maybe a couple hundred bucks of gold plate and then one of my "friends" managed to sneak off with it when my back was turned. The backing for the display was thick aluminum plate with many aluminum posts riveted into it for the circuitry in the back. That thing was built like a tank with heavy glass plates for the display parts. The new TVs have plastic sheets to disperse the lights from the LED backlights and for the display. Very interesting technology.
Yes, that's exactly the part I was breaking because I thought it was just an electrical insulator. Inside is the copper fins. The caps sealing off the main body are some sort of steel since a magnet is attracted to them but somehow they've welded those caps onto the copper. Some sort of maybe a friction weld maybe. It's a very smooth automatic looking weld but you can rip the steel caps off by tearing next to the weld. Inside the device is a coil of silvery looking metal if I remember right that leads to a copper tube that's pinched off sharp at the end under than tin cap on the end. I was told the tip of that copper tube is beryllium but you're saying the ceramic is beryllium oxide ceramic and used for heat dissipation? So, as long as you don't crush the BeO, grind it or get too friendly with you it's ok? What about those aluminum fins? They are also for heat distribution?
And what if I find a tossed out industrial microwave oven? Much larger emitters or nah?
Yeah, as long as you don't generate any particles with the insulators, they're basically just ceramics at that point. Not something you'd give the kids, but not terribly dangerous either. Just handle them like any other potentially dangerous waste. It's been a while since I've been in appliance repair, what I see suggests that manufacturers are now using Aluminum Oxides because they're cheaper and less toxic.
The aluminum body is for heat dissipation as well. You're producing a lot of waste energy in there. Commercial microwaves have bigger versions of the same thing, but when you get into RADAR system and other microwave emitters, the type of device gets more specialized and looks less like what you'd find in an oven.
, I want to personally thank you for your insight and information.
I'm a structural welder and just about all I know professionally that I've been paid for is welding technique. The hand skill or artistry of laying down good welds, trouble shooting basic malfunctions we can remedy in the field which consists of checking our wires and cables to make sure the insulation is intact, leads and grounds are properly attached and not overheating, weld size, weld quality, shielding gas, etc.
Quite a few years back before the old Lincoln wire feeders got phased out I really loved them. They were a bit smaller than the new "suitcase" sized wire feeders, easier to maneuver through manways and tight spots inside ships so when I could get hold of one, I loved it. I got hold of one and half way through the shift the dang thing just stopped working completely. Not wanting to let it go I opened it up and under the back panel was a mother board like affair. Knowing nothing I decided to just look closely and see what might be amiss. I found one small resister or diode that seemed made of glass and was blackened. So it had overheated and burned out but how vital was it to overall function? I thought, nothing ventured, nothing gained and what could go wrong at that point? It's a dead machine and it's not like I am going to make it deader and it's not like the shipyard is actually going to repair it by purchasing another circuit board like that.
I used needle nosed pliers and crushed the little resister thing. It was glass and when I did that I ended up with two small wires sticking up from the soldered connections. I found an old tin can and carefully cut a strip that was just long enough and made a crease I placed over the two wire stubs and pinched it down. Amazingly it was back up and running perfectly for the remainder of the shift. Later I was using an identical machine and the exact same thing happened so I "fixed" it the same way as it was the exact same resister than had burned out.
Anyways, I think the design of important electronics is very interesting, I like the idea of using discarded electronics in interesting ways, (repurposing) and your insight in the industry is like a drink of cold water in a desert of ignorance. I'm kind of surprised you took the time to respond so yes, much thanks.
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