Hi, yes, Ive tried this, to summarise my findings so far.
The key to not blowing the magnetron, is absorbing the uWaves, and turning them into heat. Any loose "metal" in the cavity will absorb the uWaves, and convert them into electricity=sparks! It does this so well, there is an excess of energy which promptly overloads the magnetron, overheats it, and the filiment usually burns out, rendering a $100 magnetron immediately useless. (use an old microwave oven!)
The experiments which I read, with which the aforementioned links no doubt lead to, with the ceramic casing being made from magnetite & ceramic, or carbide ceramic material are interesting, and no doubt have alot of merit, but I thought they might still be quite lossy, after reading about the process. Still with full credit going to the original author for the information provided so freely, initiating and leading to my designs, I tried a different approach.
Being an electronics technician, I know there is alot of energy lost simply bouncing around the cavity, not being fully absorbed by the uWave absorbant material.
In my case, I used refined black magnetite sand from a beach we have here in NZ called Golden Bay. I initially used magnets to seperate the black sand from the quartz, letting the sand flow in a water tank past a strong magnet, some of the magnetite jumps sideways, and sticks to the magnet which has to be cleared often. Then I ground the black sand, then graded it, and passed it past another magnet to collect ONLY the pure graded magnetite. This was then boiled a few times over to remove the sea salts, as it was from the beach, and you could still smell the sea breeze in it
My initial test was in the microwave oven standard, as is, in a 250ml beaker the magnetite heated up nicely, and absorbed the uWaves. It didn't get over (estimate) 200 degrees, before I moved on to what is to be closer to my final design.
NOTE: The following is dangerous if you DO NOT know what you are doing.
I recommend it not be done by anyone unfamiliar with the dangers involved. If you are going to do this, you MUST buy a good quality microwave leakage detector, and TEST the detector routinely. (if it is a submersable type - place it in a cup of water, in a microwave oven, turn it on, and you will get a positive indication / reading.
(note to forum moderators: if this is too bold for this forum, which deals with similar but chemical hazards, and associated warnings, allow me to either edit, or delete, but I think it is important information to share on this subject)
I dissasembled a microwave oven, and reassembled it so that the magnetron "nozzle" was lower in the cavity. There is a mesh gauze filter around the nozzle, which I placed a tight fitting stainless steel extension tube to. This extends the output location of the microwaves to just off center of a beaker siting on the rotating tray, and about 3cm up from the base of a centrally placed beaker. I left the rotation mechanism intact. I decided that, initially, it might prove to be a better option to have the microwaves being concentrated at the beaker of magnetite, but still being dispersed rotationally in the magnetite.
Placing the experiment in my underground bunker basement, sheilded by solid 2ft thick concrete walls, and having the ON button, and microwave leakage detector close at hand, initial tests prove the system to work, being able to get an intense red heat from the core of the magnetite in the beaker. I ventured closer to the setup, again with leakage detector operating, and very loud DING permeates through my bones !!!!!! exclamation !!! I almost jumped out of my boots, a second later realising, the timer had timed out, and turned the contraption off.
However on edge I was, as expected, there was no leakage from MY redesigned oven. There may be from yours, even if its an old door seal not working. CHECK! I dont know what cell damage microwaves have, other than heating them, but I for one don't take risks on such invisible radiation.
My next experiment is to concentrate the heat, I will have to disable the rotational mechanism, and build a miniture conventional furnace style oven inside the uWave oven cavity. Also, I might need a better magnetite container than a glass beaker as I expect the temperature, being concentrated, will build up considerably. Also, have to hone my skills at molding and material melting.
For now, I am distracted away from this experiment because of my newly made gold cell and gold refining processes taking up much time.
Will update, when any new experiments/information comes to hand.
So this is where I am at so far.
Regards
SK