My Tungsten Cube (2019)
thume.ca
thume.ca
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.
But I do appreciate your story about tungsten carbide, too :-)
>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.
https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...
I'd wager they're fully aware of the differences between tungsten carbide and pure tungsten, having done a doctorate about it.
Well, I guess I need to buy a new wedding ring at some point.
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.
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.
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.
You never know, when you suddenly need to move fast.
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.
This seems understated. Shouldn't you also wear armor?
You’ll be lucky to keep an eye with the same injury even with an excellent surgeon.
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.
Tungsten carbide: 15.63 g/cm3
Tungsten: 19.3 g/cm3
Pure tungsten is about 1.23 times more dense, not twice as much.
Will goggles really help? This sounds like it would rip your whole face..
When I bought my cube, I used it as an exercise to fight back against my frugality.
But it wasn't meant to be: it was delivered to the wrong address and I received a full refund.
Then my neighbor delivered it to me.
This must have caused havoc with your frugality.
The only thing that would make this story more perfect is if they'd said, "Wow. Heavy. What do you have in there? A cube of tungsten?"
He brought the rocks back to Chicago.
Our grandfather picked him up at the airport and picking up his suitcase, said, "This is really heavy. What, do you have rocks in here?"
"Yes," my brother answered.
I've had my sites set on something this size https://midwesttungsten.com/tungsten-cube/ for a while now. (about as much as I would feel safe setting down or handing to people considering the hard edges and chance of accidents) I've more than had the spending money to do it for a long time but much like the author I've just had a hard time justifying it. I suppose it's still less ridiculously than what many spend on car hobbies or whatnot. I'm sure I'll eventually get something of the nature.
I'll also add I was extremely surprised others enjoyed it as well. Of all of my desk toys/models/prints it's generated the most talk amongst friends and coworkers.
I'd like to experience a sizeable amount of iridium some day as well.
Edit: One of the most fun gifts I've received (beyond the tungsten cube) was a 1" magnesium cube. Apart from being a ridiculous fire/blinding risk capable of easily melting through the tungsten cube if set off it is even lighter than an equivalently sized aluminum cube.
[1]: https://www.quora.com/What-is-the-heaviest-metal-I-can-legal...
Unlike say, a $9000 motorcycle impulse purchase, a block of raw metal should hold it's inflation adjusted value relatively well for decades and you can sell it whenever to recoup the money.
It doesn't have the mass awareness of gold, but it's not some weird niche material either.
Also, you generally buy/sell on a 5-10% spread from the "spot" market price of the metal, depending on the quanitity you're dealing with. Dealers generally offer a closer price to spot when dealing with larger dollar value amounts of metal.
Diamonds don't have resale value anyway. They're literally a scam.
I've found aluminum globs under fires that had cans or trashed roofing thrown in. Pretty clean, since nearly everything floats on it, and easy to spot in ashes.
(Lead, on the other hand, melts at half that.)
The fires I have found aluminum globs in were long burning beach campfires and a bonfire to burn brush(big fire). The beach campfires were moderately sized but they certainly weren't bonfires built with 6-8 foot logs.
As for gold jewelry, this can swing both ways. An intricate piece with some sort of history attached may fetch a higher price from a buyer that is interested in that versus a scrap buyer that will just melt it down.
Similar analogies can be found with cars. A factory stock 1996 VW Golf will only be worth slightly higher than scrap value. Meanwhile, a 1996 VW Golf Harlequin will be worth $8-9k, its the same car but with a different factory paintjob. Effectively no difference in manufacturing costs since it was just made from different stock-painted panels but worth way more to a buyer simply due to the history and rarity. The cars both still have the same scrap value, a junkyard would buy both of them for the same price.
I mean with any luck we'll find a pure iridium asteroid and bring the thing back to earth. Iridium paperweights for everyone!
A 10mm cube of Iridium weighs ~21.9g. And from this source, costs $9000.
From the same source, a single gram is only $275. This means that due to the difficulty in working with this very dense metal, the cost of turning the Iridium into a cube is nearly $3000 (on top of the ~$6000 for the metal itself)!
The difference is far too small to give you a different feeling when holding a piece of either osmium or iridium.
While osmium and iridium are the densest pure metals, there is a range of composition in the osmium-iridium alloys which has a slightly greater density than both pure osmium and pure iridium.
That happens because the atomic concentration of Os is a little higher than that of Ir while the atomic mass of Ir is a little higher than that of Os.
While increasing the proportion of Ir in an Os-Ir alloy from 0% to 100%, there is a range where the atomic concentration decreases slower than the average atomic mass increases, so the density of the alloy becomes greater than the density of pure osmium.
At higher Ir percentages, the increase in atomic volume overcomes the increase in atomic mass, so the density becomes a little lower than for pure Os.
Unlike pure osmium, an Os-Ir alloy would not be dangerous to handle. Pure osmium is slowly oxidized in air releasing the volatile and extremely dangerous osmium tetraoxide.
In nature, the normal occurrence of both Os and Ir is as nuggets made of Os-Ir alloy, usually also containing ruthenium and very small quantities of rhodium.
Some of the cost isn't just from using the equipment, but because you'll have some evaporation from melting in vacuum. He says at the start of the article that Sacks started with a kilogram of beads:
>After melting from both sides and a lengthy cool down period (plus a couple of "ouch, where are my gloves" moments) Sacks' iridium was consolidated into a block a little over 2" square and less than 1/2" thick, weighing 1.7 pounds. It's startlingly heavy, distinctly more so than a similar sized tungsten block (which would be about 15% lighter and about 10,000% cheaper).
If true, the melt lost 22.7% of the mass, which is pretty painful. Google is saying iridium is about $167,000 per kilo right now! I assume they've got a cold trap on the vacuum line, and recovered some of the difference in weight as fine iridium dust, but the rest is going to end up coating the inside of the vacuum chamber.
If they routinely melt platinum-group metals, I wonder how often they scrap the entire chamber to melt it down and recover the evaporate.
After a production batch, the metallic foil is replaced and the used foil is chemically processed and almost 100% of the precious metals are recovered.
I'm not joking when I say one of the things I miss most about office life is decorating my desk with objects and having people react to them. Even before Delta, when things were opening back up, my office was doing "hot desks" which meant you didn't really get to personalize your space. It's understandable, but a bummer.
Magnesium only ignites easily when in thin strips?
It's also a relatively pure sample, very soft, not an alloy like you'd see with magnesium casings. The block is actually a little deformed just from dropping it on the floor once.
https://www.youtube.com/watch?v=9O551__3ppM
Another interesting fact about tungsten is that its density is 99.75% of that of gold. So essentially you can model how heavy something is if it was made out of pure gold with tungsten. Additionally, apparently gold counterfeiters sometimes put tungsten inside of gold bars to fake gold
Tungsten is the only metal you can reliably use as our machines have beam powers up to 15kW which can precisely deliver an enormous amount of heat into a pencil point sized area. Even at the common 1-3kW ranges the tungsten instantly liquefies when the beam turns on. Ive seen 1/2 thick aluminum turn into a puddle while the tungsten just gets a dent in it. You'd think copper is a good second bet but nope. Its good at heat sinking but melts way quicker.
I'm sorry - is there an error here? As I understand the rest of your comment, you use Tungsten because it does not liquify?
Glassblowers use tungsten rods to pierce borosilicate glass. When you get tungsten and a piece of glass hot, you can push the tungsten through the glass fairly easily. Tungsten doesn’t get “wet” and stick to glass at these temperatures (~2000F), unlike other metals we use such as steel or brass. We tend to buy these at the welding store (arc welders use them as electrodes or something).
Apparently a climber had one on and broke his ring finger, and the EMTs couldn't get the ring off because the finger had swollen and they couldn't cut the ring due to the strength of the metal. They ended up having to amputate and re-attach the finger (much longer and it would have had to be amputated anyway, it seems).
Thankfully the article you linked doesn't contain any images.
Similar advisories hold for printing presses, farm equipment and so on. Printing presses are particularly nasty because they tend to be so spotless that you can't tell if they're rotating or not by looking at the surface.
Terrible for rings, just go with silver if you want or need a cheap wedding ring.
Titanium / Tungsten / Silver are for people who want an inexpensive ring.
Titanium should also work great for forced amputation in the case of a broken finger I suppose...
Every metal mentioned has someone talking about losing a finger. Do you work for a silicone ring company?
For me, before I touch a lathe or mill, the ring goes in my left back pocket. Every time.
To wax poetic for a little while, Ti is lightweight, strong, warms quickly to the touch but isn't cold in winter, resists abrasion, doesn't irritate, and is almost immune to corrosion. Its strength allows a lower-profile ring without collapse, too. When making rings for our wedding, I could have used any material under the sun; titanium was our choice.
A material need not be rare to have significance, so it is with love.
I also have to test Sterling Silver as it is supposed to only be 92.5% Silver and 7.5% copper but sometimes it is adulterated with nickel and can cause me to have a breakout.
They'd also know that you can crack a tungsten ring, so they wouldn't need to do that in the first place.
Compared to say machining aluminum or steel you will be practicing some patience.
Not necessarily a bad thing to have in the world of metal working. ("increased feed speed is not a substitute for bad planning")
You can also cut tungsten with water jets loaded with abrasives, I've seen a 2" thick block cut like that, it was quite impressive. But that won't get you a surface. You'd need to start with a sheet of the right thickness.
Tungsten foil/sheet isn't that hard to come by.
Cost a small fortune too.
There's also the issue of electrode potentials: sucking a coulomb off your anode at 0.5 volts takes only half a joule, but sucking off the same coulomb at 2 volts takes 2 joules. I don't understand standard electrode potentials well enough to predict what voltage you need for efficient tungsten ECM, but on first glance at the reference table, it doesn't look particularly bleak. The tungsten entries are in the middle of the table, near things like lead, tin, and iron, rather than way down on the upper east side with hoity-toity mercury and iridium, much less out in the ethereal districts where gold and ozone dwell.
Fascinating processes by the way, and the precision that you can reach with EDM is insane.
I think the density ratio for tungsten and steel (19:8, just over 2:1) is actually more even than the atomic mass ratio (23:7, just over 3:1). So I'd think that even on a volume-per-coulomb basis ECM would cut tungsten faster, assuming comparable faradaic efficiencies. Do you have any idea about the electrode-potential question? I'm totally lost.
That's a question worth settling, from memory the speed is not so much a function of the material as it is of the current density that you can achieve with the gear you have. Thousands of Amps will get you some pretty good speeds, on the order of a cubic cm of material removed per minute for a 25KW machine.
I also wonder what would happen if you tried to plasma cut it, that should work as well.
If there is one thing I really miss from life in Canada then it was the fully equipped machine shop, that was such a great thing to have. You could go from idea to a pretty decent physical implementation fast than you could have ever mail ordered the parts and there is so much satisfaction in working metal. The plasma torch I had there was a relatively small one (12 KW) but it still cut anything an everything I ever threw at it with pretty impressive speed. But I never tried it on Tungsten. Missed chance! I suspect it wouldn't work all that well because Tungsten isn't the best conductor and probably would backsplatter all over the place from the compressed air dispersing the metal that would melt rather than evaporate so you get a puddle rather than a stream of gas.
Electrolytic processes are really interesting and complicated, and 200+ years after Davy used them to revolutionize chemistry, I think they're still underused. I'm preetty sure you can produce Fresnel reflectors for a given wavelength, for example, by anodizing aluminum foil to about a quarter-wavelength depth, and across a wide range of visible wavelengths by anodizing it to about 3 microns depth, with the electropolishing effect inherently eliminating the small asperities that make it so slow to produce lenses and mirrors by grinding.
Plasma cutting should work, but should be slower on W than on iron; WP says that at room temperature its specific heat is 24.27 J/mol/K, but at 183.84 g/mol, that's only 0.13 J/g/K. For iron the same figures are 25.10 J/mol/K and 55.845 g/mol, so 0.45 J/g/K. So tungsten should heat up three times as fast with the same power output at room temperature; but tungsten's heat of fusion is four times higher, and I think that's actually the dominant component of plasma-cutting energy consumption. But I think you have roughly four orders of magnitude more knowledge about plasma cutting than I do.
Has anybody tried that?
Reading I've done since then explains that, when anodizing, the anodized layer grows up out of the surface roughly as far as the surface gets depressed, and the anodized layer has a higher refractive index than air, so, for many purposes, you don't need to etch nearly as much metal. (The anodized layer is thin enough that it would be adequate in many applications that normally require a first-surface mirror, though not all.)
It's well known that if you're instead anodizing silicon you can fabricate a rugate filter by varying the anodizing current to vary the density of the anodized layer, that when anodizing titanium you get brilliant iridescence due to the high refractive index of the oxide and consequent strong single-layer dichroic filtering effect, and that there's a negative feedback on the current from the oxide layer thickness in all of these cases, requiring higher voltage to get a thicker oxide; this should also tend to even out small surface asperities, and is not the same effect as anodic leveling. The possibility of including such dichroic filters on the surface of the holographic reflective optics, with wavelength response tailored at a submillimeter or even submicron X-Y resolution, could be interesting for fabricating a wide variety of optical systems.
If you end up trying it, I'd love to hear about the results! If I'm not dead by then. Though I'm sure you have a long list of ideas of your own that you can't wait to try, like everyone else capable of trying this sort of thing.
All this seems to me like a crucial enabling technology for feedback control of machine tools, because light waves don't distort or change their dimensions much when the temperature in the room changes or there's a side load on your gantry.
Tungsten has an enormously high melting point, the normal way tungsten parts are produced, for typical industrial purposes such as radiation shielding, is sintering (powder + heat + pressure) to near-net-shape, finished with a machining pass.
It's so cool how they wring without magnetism.
[USE_MATERIAL_TEMPLATE:WOOD:WOOD_TEMPLATE] [STATE_NAME:ALL_SOLID:saguaro rib wood] [STATE_ADJ:ALL_SOLID:saguaro rib] [PREFIX:NONE] Density was determined experimentally. Contact Uristocrat for a sample if you want to verify this yourself. A 6g (+/- 0.1g) piece of dry Saguaro wood had a volume of approximately 14 cm^3 (+/- 1 cm^3) [SOLID_DENSITY:430] [STATE_COLOR:ALL_SOLID:ECRU]
Source: the 'raws' link on the page http://dwarffortresswiki.org/index.php/DF2014:Saguaro
It seems to me that the point of buying a cube of some metal is to feel its weight and texture, to see it respond to light. If you're just going to keep it in a capsule and never take it out, you could just have a photo or video of the metal.
What elements can you hold in your hand without either you or the element taking damage?
Some of them will oxidize and if you want to stop that you can coat them in a clear resin. I wouldn't touch lead even with the resin coating as I wouldn't trust it to not chip off.
Can be a bit dangerous for your floors, but lots of fun to hold.
I think it's fairly common to see volume and assume weight. And less volume is often assumed to be a structure issue, like expanded metal vs solid blocks of metal.
I bet a lot of energy went into creating that sphere…
It’s dense/heavy so seeing it bounce so well is somewhat paradoxical.
(Side note: it may be impossible to cut through in case of an emergency but your finger is not.)
Was seriously considering tungsten recently, but ended up going with titanium for this exact reason.
It's very important to realize that it's not a safe object, the kind you might leave on your desk at work.
If someone tries to pick it up for some reason, it's quite likely that they'll drop it.
ADD to your collection! This cube is the larger version of the world famous tungsten cube
COMPARE the density to our 2.5" Aluminum cube to enhance the experience> WHY? We thought nobody would buy our 17.6lb, 3" tungsten cube. We were so, so wrong
It wasen't till she raised her prices significantly things got going.
Wealthy measure value by price. (I don't get it.)
That's why when I buy wine for my girlfriend I don't buy the cheapest brand. It's not that I think the wine market is efficient, particularly when I'm at a supermarket that can charge whatever price they want instead of comparing prices at https://1000corks.com/; it's that I think my ignorance of wine is deeper than the market's inefficiency.
edit: I have https://news.ycombinator.com/item?id=27522826
I do this sometimes with cheaper stuff that I don't know much about. E.g. A shovel or something. I don't know much about shovels, but I know I want a good one. So I will be biased toward the more expensive shovel on the rack, assuming I can afford it. If it wasn't better, then presumably all the people that really know about shovels wouldn't buy it, so then it wouldn't be for sale.
Anyway, the logic here isn't perfect obviously, but still makes reasonable sense and works out okay for stuff you can easily afford and don't know much about.
Now I’m thinking it must have been the metal’s low density.
It weighs over 40 lbs and it's almost impossible to lift with one hand.
I haven't smashed anything with it yet
I wish I could afford an osmium cube. I guess tungsten is the best cheapest-yet-still-heavy option.
If tungsten isn't dense-enough for you, consider platinum or rhenium.
I'm not saying one is a better choice than the other, but I know which one I'd get.
(Description says it's "great for melting". Good luck with that!)
One additional benefit that gives me more joy than fidgeting with it: it is great educational prop. Kids that visit my place have a habit of picking it up, either by their own initiative or prompted by me. Being surprised at the weight they start asking question and are then receptive to hear me give a short explanation. I love that curiosity.
https://www.tungstenheavypowder.com/tungsten-balls-spheres-c...
If you get the set that has the copper cube beware that the copper one will oxidize and discolor if you touch it a lot.
Tungsten weights are smaller, so the center of gravity can be slightly higher if you elevate the weights.
The product page says "Simply position the weights on your pinewood derby car and super glue them in place."
So if you're just glueing them to a standard model without elevating the tungsten weights somehow, they would actually be less effective than a less dense material, because the center of gravity would be lower.
If you did elevate the tungsten weights, whatever height that would match the top height with standard weights, the extra amount of energy would most likely be negligeable, and possibly lost due to variations in the track. Over a hundred races it would probably come out ahead slightly more ahead, but Pinewood Derby races are single elimination.
If one was sparing zero expense, using wind modeling software, etc for their Pinewood Derby, then yes, tungsten weights would be the way to go.
(I need to learn how to use wind modeling software now.)
I've found that I really love it, and now we may not replace mine at all. It's hilariously heavy and has a nice brushed finish.
"Exclusive: Fake-branded bars slip dirty gold into world markets"
https://www.reuters.com/article/us-gold-swiss-fakes-exclusiv...
If anyone wants to compare, my order ID is 10000107xx ;)
Now I have a tracking number for a cube of tungsten that will arrive at my office by tomorrow afternoon.
Happens.
I keep it next to a similarly sized, nearly spherical light gray pumice stone I picked up near Crater Lake years ago. Satisfyingly light!
I was given a tungsten carbide ring that’s supposed to be easy on the skin, but it rotted my flesh. I tried not to read anything into it.
I love letting people hold it. I call it my heavy ball.
Ever since then I have been vaguely considering buying a tungsten cube as a curiosity. I am bemused to find that others on hacker news seem to have arrived at the same idea.
Mercury is denser than lead but doesn't have a well-defined market price any more and has certain disadvantages. Many mercury amalgams would be a better substitute in many circumstances, but they might impose high costs on you for reasons that come down to pure superstition.
Or did you really spend $5,000 on a machine for your hobby of making cubes just so you can hold them?
If you are serious, I think we could be friends. Maybe I should make a subreddit for people like us?
note that I'm mainly doing wood because the x-carve can't carve aluminum easily (no idea about tungsten). If I could make metal cubes, I would.
The actual hobby here is all sorts of wood projects, like tables, arts, etc, but I still make small geometry pieces all the time because I enjoy 3D graphical objects in the real world.
I mainly read https://www.reddit.com/r/CNC/ but you may also find this interesting: https://www.instructables.com/Turners-Cube-Manual-Machine/
Almost without fail, every time I walk by it I pick it up.
And without fail, every time is satisfying.
(The 3" cube weighs ~18 pounds.)
https://www.smart-elements.com/shop/tungsten-precision-densi...
https://www.smart-elements.com/shop/tungsten-electrode-99-95...
Also pure tungsten is often excessively brittle.
I also have a magnesium cube. Really amazing to compare the weights.
It's hard to find a good source for details about this display, but he has cubbyholes for all of the lanthanides and actinides, so there must be some that don't have the actual element being represented.
Not only that, but it's only true francium if it comes from France.
(the picture is a separate 3kg sphere he bought after the cube)
If you're gonna be pedantic then try to do a good job of it.
You bought a piece of metal at vastly inflated prices for a very narrow range of performance over a specific set of conditions. Nothing more. Being the hardest isn't being the best. Tungsten is extraordinarily brittle. A hard drop on concrete could crack it.
I'd also argue without a MA (metal analysis or labsheet) you probably bought some tungsten. Lead, slag, tin and other undesirable byproducts also weigh a lot. Your cube, without proper inspection, may also be slightly radioactive as its likely sourced from scrap. This could be good or bad, but the cube most definitely isn't a meaningful purchase.
As for the value to a consumer. That comes almost entirely from its density not its hardness, something you'd know if you read OP.
As for the "vastly inflated prices" if you have the ability to produce and sell 1 kilogram cubes with the side length of an inch and a half for significantly less than OP paid then you should consider selling that information and retiring.
Apparently wholesale tungsten costs US$30/kg, which is about one fourth the US$130 cost the guy paid. I'd think either wire EDM or wire ECM would be able to dice tungsten into featureless cubes for a lot less than US$100/kg. Its brittleness wouldn't be a problem.
Also, it could very easily be impure, or even not tungsten at all; lots of people have gotten tricked into buying tungsten-carbide jewelry they thought was tungsten, and tungsten carbide isn't even metal. The Amazon seller says it's actually 5% nickel and iron, though I'm not clear whether it's an alloy or a powder-metallurgy sinter using those metals as sintering aids. Alloys aren't necessarily less dense than their densest pure component, so impurities might not even lower the density. X-ray fluorescence would be a cheap way to detect heavy-metal impurities (though not, say, boron, carbon, or nitrogen).
The guy is excited about how it's durable and will last for a long time. I think he will be disappointed if it really is so brittle that he chips the corner off by dropping it on the floor. Probably the nickel and iron will prevent that.
I don't know... Seems your own post has missed the mark pretty sharply as well.
To me, it was abundantly clear that the purpose of this tungsten cube is not for engineering or practical utility.
I think a better desk objet is a Curta calculator.
I would think you can easily sell it for the same or better price. It's like gold. It's a capacitor of wealth