chemistry hacks

644 Articles

A Deep Dive Into Molten Bismuth

October 16, 2025 by 2 Comments

Bismuth is known for a few things: its low melting point, high density, and psychedelic hopper crystals. A literal deep-dive into any molten metal would be a terrible idea, regardless of low melting point, but [Electron Impressions]’s video on “Why Do Bismuth Crystals Look Like That” may be the most educational eight minutes posted to YouTube in the past week.

The whole video is worth a watch, but since spoilers are the point of these articles, we’ll let you in on the secret: it all comes down to Free Energy. No, not the perpetual motion scam sort of free energy, but the potential that is minimized in any chemical reaction. There’s potential energy to be had in crystal formation, after all, and nature is always (to the extent possible) going to minimize the amount left on the table.

In bismuth crystals– at least when you have a pot slowly cooling at standard temperature and pressure–that means instead of a large version of the rhombahedral crystal you might naively expect if you’ve tried growing salt or sugar crystals in beakers, you get the madman’s maze that actually emerges. The reason for this is that atoms are preferentially deposited onto the vertexes and edges of the growing crystal rather than the face. That tends to lead to more vertexes and edges until you get the fractal spirals that a good bismuth crystal is known for. (It’s not unlike the mechanism by which the dreaded tin whiskers grow, as a matter of fact.)

Bismuth isn’t actually special in this respect; indeed, nothing in this video would not apply to other metals, in the right conditions. It just so happens that “the right conditions” in terms of crystal growth and the cooling of the melt are trivial to achieve when melting Bismuth in a way that they aren’t when melting, say, Aluminum in the back yard. [Electron Impressions] doesn’t mention because he is laser-focused on Bismuth here, but hopper crystals of everything from table salt to gold have been produced in the lab. When cooling goes to quick, it’s “any port in a storm” and atoms slam into solid phase without a care for the crystal structure, and you get fine-grained, polycrystaline solids; when it goes slowly enough, the underlying crystal geometry can dominate. Hopper crystals exist in a weird and delightful middle ground that’s totally worth eight minutes to learn about.

Aside from being easy to grow into delightful crystals, bismuth can also be useful when desoldering, and, oddly enough, making the world’s fastest transistor.

Continue reading “A Deep Dive Into Molten Bismuth” →

A metal needle tip comes to a point against a white background. A scale bar in the lower left shows a 300 micrometer length.

Etching Atomically Fine Needle Points

October 13, 2025 by 23 Comments

[Vik Olliver] has been extending the lower resolution limits of 3D printers with the RepRapMicron project, which aims to print structures with a feature size of ten micrometers. A molten plastic extruder would be impractical at such small scales, even if a hobbyist could manufacture one small enough, so instead [Vik]’s working on a system that uses a very fine needle point to place tiny droplets of UV resin on a substrate. These points have to be sharper than anything readily available, so his latest experiments have focused on electrochemically etching his own needles.

The needles start with a fine wire, which a 3D-printed bracket holds hanging down into a beaker of electrolyte, where another electrode is located. By applying a few volts across the circuit, with the wire acting as an anode, electrochemical erosion eventually wears through the wire and it drops off, leaving an atomically sharp point. Titanium wire performs best, but Nichrome and stainless steel also work. Copper wire doesn’t work, and by extension, nor does the plated copper wire sometimes sold as “stainless steel” by sketchy online merchants.

The electrolyte was made from either a 5% sodium chloride solution or 1% nitric acid. The salt solution produced a very thin, fine point, but also produced a cloudy suspension of metal hydroxides around the wire, which made it hard to tell when the wire had broken off. The goal of nitric acid was to prevent hydroxide formation; it produced a shorter, blunter tip with a pitted shaft, but it simply etched the tip of the wire to a point, with the rest of the wire never dropping off. Some experimentation revealed that a mixture of the two electrolyte solutions struck a good balance which etched fine points like the pure salt solution, but also avoided cloudy precipitates.

If you’re interested in seeing more of the RepRapMicron, we’ve looked at a previous iteration which scribed a minuscule Jolly Wrencher in marker ink. On a more macro scale, we’ve also seen one 3D printer which used a similar resin deposition scheme.

Tube Furnace Is The Real Hotness

September 25, 2025 by 11 Comments

We aren’t sure what [theglassman] is working on, but based on his recent projects, we think it is probably something interesting. He’s been decapping ICs, growing oxide on silicon substrates, and has built a tube furnace capable of reaching 1200 °C.

What would you do with something that can melt cast iron? We aren’t sure, but maybe you’ll tell us in the comments. We do have a fair idea of what [theglassman] is doing, though.

The core of the oven is a quartz tube. Insulation is via refractory cement and alumina ceramic wool. The heating itself is classic Nichrome wire and a tiny thermocouple. The real key, though, is to the proper controller. [theglassman] suggests a ramp/soak controller. These allow you to program sequences that heat up and then stop, which, if done properly, can prevent your fragile quartz tube from cracking.

Continue reading “Tube Furnace Is The Real Hotness” →

Blue Alchemist Promises Rocket Fuel From Moon Dust

September 22, 2025 by 16 Comments

Usually when an alchemist shows up promising to turn rocks into gold, you should run the other way. Sure, rocket fuel isn’t gold, but on the moon it’s worth more than its weight in the yellow stuff. So there would be reason to be skeptical if this “Blue Alchemist” was actually an alchemist, and not a chemical reactor under development by the Blue Origin corporation.

The chemistry in question is quite simple, really: take moon dust, which is rich in aluminum silicate minerals, and melt the stuff. Then it’s just a matter of electrolysis to split the elements, collecting the gaseous oxygen for use in your rockets. So: moon dust to air and metals, just add power. Lots and lots of power.

Melting rock takes a lot of temperature, and the molten rock doesn’t electrolyse quite as easily as the water we’re more familiar with splitting. Still, it’s very doable; this is how aluminum is produced on Earth, though notably not from the sorts of minerals you find in moon dust. Given the image accompanying the press release, perhaps on the moon the old expression will be modified to “make oxygen while the sun shines”.

Hackaday wasn’t around to write about it, but forward-looking researchers at NASA, expecting just such a chemical reactor to be developed someday, proposed an Aluminum/Liquid Oxygen slurry monopropellant rocket back in the 1990s.

That’s not likely to be flying any time soon, but of course even with the Methalox rockets in vogue these days, there are appreciable cost savings to leaving your oxygen and home. And we’re not biologists, but maybe Astronauts would like to breathe some of this oxygen stuff? We’ve heard it’s good for your health.

Unobtanium No More; Perhaps We Already Have All The Elements We Need

September 19, 2025 by 81 Comments

It’s been a trope of the news cycle over the past decade or so, that there’s some element which we all need but which someone else has the sole supply, and that’s a Bad Thing. It’s been variously lithium, or rare earth elements, and the someone else is usually China, which makes the perfect mix of ingredients for a good media scare story. Sometimes these things cross from the financial pages to the geopolitical stage, even at times being cited in bellicose language. But is there really a shortage?

The Colorado School of Mines say perhaps not, as they’ve released a paper  from an American perspective pointing out that the USA already has everything it needs but perhaps doesn’t realize it. We’re surprised it seems to have passed unnoticed in a world preoccupied with such matters.

We’ve covered a few stories about mineral shortages ourselves, and some of them even point to the same conclusion reached by the School of Mines, that those mineral riches lie not in the mines of China but in the waste products closer to American industry. In particular they point to the tailings from existing mines, a waste product of which there is a huge quantity to hand, and which once stripped of the metal they were mined for still contain enough of the sought-after ones to more than satisfy need.

The history of mining from medieval lead miners processing Roman tailings to 19th century gold miners discovering that their tailings were silver ore and on to the present day, includes many similar stories. Perhaps the real story is economic both in the publicity side and the mining side, a good scare story sells papers, and it’s just cheaper to buy your molybdenum from China rather than make your own. We’ll keep you posted if we see news of a tailings bonanza in the Rockies.

When Is Your Pyrex Not The Pyrex You Expect?

September 17, 2025 by 22 Comments

It’s not often that Hackaday brings you something from a cooking channel, but [I Want To Cook] has a fascinating look at Pyrex glassware that’s definitely worth watching. If you know anything about Pyrex it’s probably that it’s the glass you’ll see in laboratories and many pieces of cookware, and its special trick is that it can handle high temperatures. The video takes a look at this, and reveals that not all Pyrex is the same.

Pyrex was a Corning product from the early 20th century, and aside from its many laboratory and industrial applications has been the go-to brand for casserole dishes and much more in the kitchen ever since. It’s a borosilicate glass, which is what gives it the special properties, or at least in some cases it used to be a borosilicate glass. It seems that modern-day American Pyrex for the kitchen is instead a soda glass, which while it still makes a fine pie dish, doesn’t quite have the properties of the original.

The video explains some of the differences, as well as revealing that the American version is branded in lower case as pyrex while the European version is branded uppercase as PYREX and retains the borosilicate formulation. Frustratingly there’s no quick way to definitively tell whether a piece of lower-case pyrex is soda glass or not, because the brand switch happened before the formulation switch.

In all probability in the kitchen it makes little difference which version you own, because most users won’t give it the extreme thermal shock required to break the soda version. But some Hackaday readers do plenty of experiments pushing the limits of their glassware, so it’s as well to know that seeking out an older PYREX dish could be a good move.

If you’d like to know more about glass, we’ve got you covered.

Continue reading “When Is Your Pyrex Not The Pyrex You Expect?” →

A piece of perovskite crystal

Perovskite Solar Cell Crystals See The Invisible

September 16, 2025 by 14 Comments

A new kind of ‘camera’ is poking at the invisible world of the human body – and it’s made from the same weird crystals that once shook up solar energy. Researchers at Northwestern University and Soochow University have built the first perovskite-based gamma-ray detector that actually works for nuclear medicine imaging, like SPECT scans. This hack is unusual because it takes a once-experimental lab material and shows it can replace multimillion-dollar detectors in real-world hospitals.

Current medical scanners rely on CZT or NaI detectors. CZT is pricey and cracks like ice on a frozen lake. NaI is cheaper, but fuzzy – like photographing a cat through steamed-up glass. Perovskites, however, are easier to grow, cheaper to process, and now proven to detect single photons with record-breaking precision. The team pixelated their crystal like a smartphone camera sensor and pulled crisp 3D images out of faint radiation traces. The payoff: sharper scans, lower radiation doses, and tech that could spread beyond rich clinics.

Perovskite was once typecast as a ‘solar cell wonder,’ but now it’s mutating into a disruptive medical eye. A hack in the truest sense: re-purposing physics for life-saving clarity.