Fair warning: if you’re going to try to mold uranium glass in a microwave kiln, you might want to not later use the oven for preparing food. Just a thought.
Granted, uranium glass isn’t as dangerous as it might sound. Especially considering its creepy green glow, which almost seems to be somehow self-powered. The uranium glass used by [gigabecquerel] for this project is only about 1% U3O8, and isn’t really that radioactive. But radioactive or not, melting glass inside a microwave can be problematic, and appropriate precautions should be taken. This would include making the raw material for the project, called frit, which was accomplished by smacking a few bits of uranium glass with a hammer. We’d recommend a respirator and some good ventilation for this step. Graphite Electrode
The powdered uranium glass then goes into a graphite-coated plaster mold, which was made from a silicone mold, which in turn came from a 3D print. The charged mold then goes into a microwave kiln, which is essentially an insulating chamber that contains a silicon carbide crucible inside a standard microwave oven. Although it seems like [gigabecquerel] used a commercially available kiln, we recently saw a DIY metal-melting microwave forge that would probably do the trick.
The actual casting process is pretty simple — it’s really just ten minutes in the microwave on high until the frit gets hot enough to liquefy and flow into the mold. The results were pretty good; the glass medallion picked up the detail in the mold, but also the crack that developed in the plaster. [gigabecquerel] thinks that a mold milled from solid graphite would work better, but he doesn’t have the facilities for that. If anyone tries this out, we’d love to hear about it.
“Not THAT radioactive”. Yeah yeah. I heard this about an old camera lens that is supposed to be “not THAT radioactive|. In the 60s Japanese firms (Pentax in particular) used Thorium doped glass because it has a better refractive index. So for fun I put one with the rear element on my Geiger Counter. “Not that radioactive” is 30x background (and I live next to a nuclear plant!). The Geiger counter’s alarm went off and flashed red which means “Inform the authorities”.
In principle this is not as bad as it sounds. Thorium Glass is an Alpha radiator which definitely cannot not get through a camera body or the mirror and eyepiece of the camera. It also cannot penetrate skin. But there are 2 notable exceptions to that rule. If it gets in your lungs alpha radiation is pretty dangerous. And it can affect the only part of your exterior which is covered with live cells. Which happens to be the Cornea. In the 60s people who ground the glass in the factory did get lung cancer because they inhaled the dust. As for looking through the lens with my cornea next to the rear element, no way.
The cameras body and mirror in die 60s protected your eyes and film. But in my new MirrorLESS Camera the sensor is parked, open, naked, vulnerable 15mm from an alpha source the whole time, all the time. No way that happens.
The lens went on EBay into the mail.
I’m pretty sure that it’s been determined that while you can see some extra noise in long exposures with certain levels of radiation, your cmos sensor will keep working for a long time. Nasa probably has some data written up about it. And there’s probably more benefit to your corneas in wearing sunglasses outdoors as long as your eyepiece isn’t radioactive. Sort of like how I probably get exposed to more radiation living near a coal plant than you get exposed to by your nuclear plant, not every intentional use of radioactive material is worse than unintentional sources. On the other hand, having used thoriated gas lantern mantles, which crumble and get heated to incandescence in exactly the way that old lenses don’t, some intentional uses are a lot worse than the lenses. I’ve probably been exposed to enough chemical and nuclear stupidity not to chance adding the lens, but for most people it’s probably fine.
You can also easily acquire some thoriated tungsten electrodes for TIG welding. 1% thorium also produces quite a lot of clicks on the geiger müller tube ;-)
Good point! Just in case managing regular fumes and ultraviolet from the arc wasn’t enough, let’s add some thorium!
This one is worse than most because when you contaminate the tungsten by, say, touching the weld metal or the feeder rod, you have to grind away the tungsten to expose a new point and remove all the contamination. Most of us welders use a standard bench grinder to do this, which throws dusty fragments of thorium everywhere. (This is why I’ve moved to lanthanum doped tungsten.)
I can’t imagine the wear from the hot arc is negligible either; they’re replaceable components for a reason.
Sissy. A real weldor would wear his chest full of thoriated tungsten with pride! Last time I went in for a chest x-ray the films lit up like a cchrostmas tree! It was almost like looking up at the sky on a clear dark night. Oh i enjoy every aspect of letal working… Ahh… mercury.. sweetest of the transition metals…
“(and I live next to a nuclear plant!)”. No. There is essentially no increase in radiation exposure (0.01 millirem per year) living near a nuclear plant. Those living near coal fired power plants are exposed to more actually.
30 times background is 10 times less than in an airplane, yet pilots and plane stewards aren’t dropping dead.
Vivitar did a family of F1.9 thoriated glass camera lenses and the 35mm wideangle was fab. I would have liked the 28mm f1.9 but never found one.
Glass-slumping is quite a normal activity in plain old resistance-wire kilns too, isn’t it? That’s how my hackerspace does it, no microwaves or special crucibles required.
It turns out these are really cheap. And basic microwaves can be pretty cheap nowadays too, even if you haven’t got a spare.
Is the uranium glass made with natural uranium ore, depleted uranium or something else?
It’s depleted Uranium, around 0.3%. Here’s more info on the glass I used: https://gigabecquerel.wordpress.com/2022/03/08/czech-this-out/
Broke up some uranium glass and melted it into a mold? That’s as much of a hack as taking apart an old digital clock then putting the pieces into a box and claiming to have “made a clock”.
made a clock…in your microwave!
“Nice clock, Ahmed. Wanna bring it to the White House?”
I can’t imagine the wear from the hot arc is negligible either; they’re replaceable components for a reason.
Gah, I hate this glitch. Can I just reply to the comment I replied to?!
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