[MgB2]

I used to work with tungsten carbide cubes during my PhD thesis. They're used in multianvil high-pressure synthesis. With the right setup you can reach almost 20 GPa of pressure. Not as much as with diamond anvil cells, but you have more reasonable sample sizes (a few milligrams). And thats still like the pressure pretty deep into Earth's mantle.

I also used the opportunity to snap a neat picture of a polished WC cube: https://imgur.com/C2YiMqb.jpg

I always had fun handing them over to students because everyone is surprised by the sheer weight of these things.

Tungsten carbide is actually quite dangerous after it has been subjected to a lot of stress (Such as being stuck into a 1000 t press for a high-pressure synthesis). They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles.

[fywacro]

FYI, tungsten carbide (tungsten + carbon) is a different substance from the pure metal tungsten... They have very different physical properties.

But I do appreciate your story about tungsten carbide, too :-)

[fraa-orolo]

> FYI

I'd wager they're fully aware of the differences between tungsten carbide and pure tungsten, having done a doctorate about it.

[User23]

The FYI might be poor phrasing, but GP is right that many people confuse the two. This isn't helped by many sellers of novelty "tungsten" online selling tungsten carbide and mentioning it in the fine print, if at all.

[paulgerhardt]

If anyone knows where to get a tungsten cube I would be interested. I’ve wanted one since reading this post a few years ago but every vendor usually sells alloys.

[daerhan]

This vendor sells cubes of various sizes that they claim to be 99.95% tungsten - https://luciteria.com/metal-cubes/tungsten-cube. I have one of the 1cc cubes and it seems to be of good quality. They also sell a lot of other exotic elements.

[paulgerhardt]

Perfect, thank you! Looking it seems they both have a kilo of pure tungsten in cube form measuring 38.1mm^3 or a kilo of tungsten carbide measuring 40mm^3.

[falcrist]

I honestly wouldn't have noticed that the Midwest Tungsten Service products weren't pure tungsten, but when I went back to the amazon page, I found a note from the seller:

>The tungsten sphere is 90% tungsten with nickel/iron for the remainder, the aluminum sphere is 6061 alloy.

This actually seems to apply to most of their products. Not just the spheres.

If you search Amazon for "pure tungsten", you'll find vendors selling cubes that are at least more pure than this vendor's stuff. There are also other items that claim to be high purity tungsten.

[HarryHirsch]

Can't blame them for selling alloy. Pure tungsten is extremely brittle and virtually unmachineable. So they'll sell you nickel alloy, because you can work that to tolerance. No powder metallurgy required.

[tyingq]

Aliexpress, with the usual gamble as to what you actually receive :)

https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...

[dvaun]

> They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles.

Well, I guess I need to buy a new wedding ring at some point.

[hutzlibu]

Your marriage yields the equivalent of 1000t pressure stress on your wedding ring?

[tomcam]

Mine does

[sprkwd]

Mine did

[theIV]

I accidentally dropped my tungsten carbide wedding band on my kitchen tile floor. Now, I have 4 shattered pieces of tungsten carbide sitting in a box on my desk.

[downrightmike]

Sounds like the start to an epic quest.

[jtms]

The four shards must be reunited for the prophecy to be fulfilled!

[analog31]

Given that my wedding ring is permanently egg shaped due to some impact that I don't even remember, I'll stick with gold.

[JoachimS]

Mine too, but mine got deformed when I held my fingers behind a plank I was mounting to a concrete wall using a power screw driver, and didn't engage my brain safety-wise.

[jtms]

Sounds like a good night!

[toiletaccount]

i read something about a guy shattering his tungsten wedding band on his wedding night, after deciding that slapping his hands on concrete was how you're supposed to dance.

professional advice: don't use an exotic metal for your wedding band. some fire departments can't cut it if your ring finger swells up.

[sterlind]

Apparently you can shatter tungsten rings with a strong pair of locking pliers. See this amazing medical journal article in which "the Internet was consulted which led to a YouTube video": https://www.hindawi.com/journals/criem/2016/8164524/

[dreamcompiler]

Or you could just not wear rings at all. I'm an EMT and the only trauma injury that gives me the creeps is degloving. Happens e.g. when somebody falls off a ladder and their ring gets caught on a nail on the way down. Don't google it.

[kwhitefoot]

Many years ago I was told about a British Post Office training film from the days when they were responsible for the telephone system.

A technician climbed a telegraph pole without proper equipment and wearing a ring. He and slipped and tore off the finger wearing the ring. The way it was described to me was horrific, the tendons were pulled out of his hand as well.

I've never seen it so I don't know for sure if it really was like that but the description alone was sufficient for me and I always remove my rings when doing anything like that.

[ilikepi]

Or wear a silicone one. They are cheap to replace and (in theory) will break if they catch on something. I have a couple from SafeRingz[1] (not affiliated), but there are plenty of cheaper ones on Amazon.

[1]: https://www.saferingz.com/

[tmm]

> the only trauma injury that gives me the creeps is degloving

I worked with a guy who was missing most of his ring finger. I asked him about it one day at lunch. I regretted it.

[lobocinza]

Specially maxillofacial degloving. But modern surgery is amazing.

[scandox]

Yeah I have this about scarves ever since I read about how Isadora Duncan died.

[DavidAdams]

I have a very cool ring made of tungsten carbide and carbon fiber. But I stopped wearing it precisely because of hearing stories like this.

[hutzlibu]

Thats the reason I never wore any rings or necklace, or co.

You never know, when you suddenly need to move fast.

[Cthulhu_]

There was a scene in The Fountain where the guy ends up tattooing himself a wedding band after losing his wedding ring.

[Brendinooo]

Tungsten (carbide) ring wearer here: I've looked into this and supposedly they're easy enough to crack.

Lucky for me, I bought mine for ~$30 on eBay and it's always been a bit too big for me. If my finger only swells a bit, it could probably still come off.

[downrightmike]

Easy enough to cut the finger off and reattach later. Seriously that's what they do.

[SilverRed]

I have heard claims that they are actually safer since if you take a hit, a metal ring could squeeze your finger while a WC ring will shatter instead.

[ncmncm]

It is, for all practical purposes, impossible to buy an actual tungsten ring; all sold as "tungsten" are really just tungsten carbide ceramic. Really-pure elemental tungsten is not difficult to machine, unlike common tungsten alloys.

A company near Los Angeles, American Metals, will sell you a 0.99999 pure tungsten boule for a few $thousand. You can ask for it to have a nominal (e.g.) 22 mm outer diameter, and slice it up and core out a collection of rings. The boule melt pattern on the outside is really appealing.

You can sell the rest of the rings, then, provided you can find a way to cut through the noise of the $2 tungsten-carbide hawkers. You might be tempted to paint on a design with resist and electro-plate gold where it isn't.

The scrap you cored out is pretty valuable. Maybe have the cores cut out as discs, instead of just drilling, because the "swarf" would be really hard to melt! They would resemble very heavy, thick coins; you can use a CNC machine to mill designs onto them, if you like.

[desdiv]

>Tungsten carbide is not heavy at all. Pure tungsten is twice as dense.

Tungsten carbide: 15.63 g/cm3

Tungsten: 19.3 g/cm3

Pure tungsten is about 1.23 times more dense, not twice as much.

[ncmncm]

I am corrected.

[thaumasiotes]

> They have the mean tendecy to explode into super sharp pieces when you're not expecting it, so wear goggles.

This seems understated. Shouldn't you also wear armor?

[danielheath]

A 3mm deep cut 2cm long will heal just fine on your arm with minimal first aid.

You’ll be lucky to keep an eye with the same injury even with an excellent surgeon.

[kragen]

Oh, that's really interesting! I guess the energy is storred in them because they underwent some plastic deformation in the press? Is that from plasticity of the WC itself or from a sintering aid such as cobalt? I would have thought pure WC would have no plasticity at all at room temperature or anything nearby.

[nextaccountic]

> They have the mean tendency to explode into super sharp pieces when you're not expecting it, so wear goggles.

Will goggles really help? This sounds like it would rip your whole face..

[NL807]

Those things look awesome. What's cost of getting one of these?