2025-06-02 22:00:41
To the average person, walking into a flour- or sawmill and seeing dust swirling around is unlikely to evoke much of a response, but those in the know are quite likely to bolt for the nearest exit at this harrowing sight. For as harmless as a fine cloud of flour, sawdust or even coffee creamer may appear, each of these have the potential for a massive conflagration and even an earth-shattering detonation.
As for the ‘why’, the answer can be found in for example the working principle behind an internal combustion engine. While a puddle of gasoline is definitely flammable, the only thing that actually burns is the evaporated gaseous form above the liquid, ergo it’s a relatively slow process; in order to make petrol combust, it needs to be mixed in the right air-fuel ratio. If this mixture is then exposed to a spark, the fuel will nearly instantly burn, causing a detonation due to the sudden release of energy.
Similarly, flour, sawdust, and many other substances in powder form will burn gradually if a certain transition interface is maintained. A bucket of sawdust burns slowly, but if you create a sawdust cloud, it might just blow up the room.
This raises the questions of how to recognize this danger and what to do about it.
In an industrial setting, people will generally acknowledge that oil refineries and chemical plants are dangerous and can occasionally go boom in rather violent ways. More surprising is that something as seemingly innocuous as a sugar refinery and packing plant can go from a light sprinkling of sugar dust to a violent and lethal explosion within a second. This is however what happened in 2008 at the Georgia Imperial Sugar refinery, which killed fourteen and injured thirty-six. During this disaster, a primary and multiple secondary explosions ripped through the building, completely destroying it.
As described in the US Chemical Safety Board (USCSB) report with accompanying summary video (embedded below), the biggest cause was a lack of ventilation and cleaning that allowed for a build-up of sugar dust, with an ignition source, likely an overheated bearing, setting off the primary explosion. This explosion then found subsequent fuel to ignite elsewhere in the building, setting off a chain reaction.
What is striking is just how simple and straightforward both the build-up towards the disaster and the means to prevent it were. Even without knowing the exact air-fuel ratio for the fuel in question, there are only two points on the scale where you have a mixture that will not violently explode in the presence of an ignition source.
These are either a heavily saturated solution — too much fuel, not enough air — or the inverse. Essentially, if the dust-collection systems at the Imperial Sugar plant had been up to the task, and expanded to all relevant areas, the possibility of an ignition event would have likely been reduced to zero.
In the context of dust explosions, it’s somewhat discomforting to realize just how many things around us are rather excellent sources of fuel. The aforementioned sugar, for example, is a carbohydrate (Cm(H2O)n). This chemical group also includes cellulose, which is a major part of wood dust, explaining why reducing dust levels in a woodworking shop is about much more than just keeping one’s lungs happy. Nobody wants their backyard woodworking shop to turn into a mini-Imperial Sugar ground zero, after all.
Carbohydrates aren’t far off from hydrocarbons, which includes our old friend petrol, as well as methane (CH4), butane (C4H10), etc., which are all delightfully combustible. All that the carbohydrates have in addition to carbon and hydrogen atoms are a lot of oxygen atoms, which is an interesting addition in the context of them being potential fuel sources. It incidentally also illustrates how important carbon is for life on this planet since its forms the literal backbone of its molecules.
Although one might conclude from this that only something which is a carbohydrate or hydrocarbon is highly flammable, there’s a whole other world out there of things that can burn. Case in point: metals.
On December 9, 2010, workers were busy at the New Cumberland AL Solutions titanium plant in West Virginia, processing titanium powder. At this facility, scrap titanium and zirconium were milled and blended into a powder that got pressed into discs. Per the report, a malfunction inside one blender created a heat source that ignited the metal powder, killing three employees and injuring one contractor. As it turns out, no dust control methods were installed at the plant, allowing for uncontrolled dust build-up.
As pointed out in the USCSB report, both titanium and zirconium will readily ignite in particulate form, with zirconium capable of auto-igniting in air at room temperature. This is why the milling step at AL Solutions took place submerged in water. After ignition, titanium and zirconium require a Class D fire extinguisher, but it’s generally recommended to let large metal fires burn out by themselves. Using water on larger titanium fires can produce hydrogen, leading conceivably to even worse explosions.
The phenomenon of metal fires is probably best known from thermite. This is a mixture of a metal powder and a metal oxide. After ignited by an initial source of heat, the redox process becomes self-sustaining, providing the fuel, oxygen, and heat. While generally iron(III) oxide and aluminium are used, many more metals and metal oxides can be combined, including a copper oxide for a very rapid burn.
While thermite is intentionally kept as a powder, and often in some kind of container to create a molten phase that sustains itself, it shouldn’t be hard to imagine what happens if the metal is ground into a fine powder, distributed as a fine dust cloud in a confined room and exposed to an ignition source. At that point the differences between carbohydrates, hydrocarbons and metals become mostly academic to any survivors of the resulting inferno.
As should be quite obvious at this point, there’s no real way to fight a dust explosion, only to prevent it. Proper ventilation, preventing dust from building up and having active dust extraction in place where possible are about the most minimal precautions one should take. Complacency as happened at the Imperial Sugar plant merely invites disaster: if you can see the dust build-up on surfaces & dust in the air, you’re already at least at DEFCON 2.
A demonstration of how easy it is to create a solid dust explosion came from the Mythbusters back in 2008 when they tested the ‘sawdust cannon’ myth. This involved blowing sawdust into a cloud and igniting it with a flare, creating a massive fireball. After nearly getting their facial hair singed off with this roaring success, they then tried the same with non-dairy coffee creamer, which created an even more massive fireball.
Fortunately the Mythbusters build team was supervised by adults on the bomb range for these experiments, as it shows just how incredibly dangerous dust explosions can be. Even out in the open on a secure bomb range, never mind in an enclosed space, as hundreds have found out over the decades in the US alone. One only has to look at the USCSB’s dust explosions statistics to learn to respect the dangers a bit more.
2025-06-02 19:00:38
Fiber lasers aren’t nearly as common as their diode and CO2 cousins, but if you’re lucky enough to have one in your garage or local makerspace, this technique for depositing thin films of metals in [Breaking Taps] video, embedded below, might be worth checking out.
It’s a very simple hack: a metal shim or foil is sandwiched between two pieces of glass, and the laser is focused on the metal. Etching the foil blasts off enough metal to deposit a thin film of it onto the glass. From electron microscopy, [Breaking Taps] reveals that what’s happening is that microscopic molten metal droplets are splashing up to the ̶m̶e̶t̶a̶l̶ glass, rather than this being any kind of plasma process like sputtering. He found this technique worked best with silver of all the materials tested, and there were a few. While copper worked, it was not terribly conductive — he suggests electroplating a thicker layer onto the (probably rather oxidized) copper before trying to solder, but demonstrates soldering to it regardless, which seems to work.
This might be a neat way to make artistic glass-substrate PCBs. More testing will be needed to see if this would be worth the effort over just gluing copper foil to glass, as has been done before. [Breaking Taps] suspects, and we agree, that his process would work better under an inert atmosphere, and we’d like to see it tried.
One thing to note is that, regardless of atmosphere, alloys are a bit iffy with this technique, as the ‘blast little drops off’ process can cause them to demix on the glass surface. He also reasons that ‘printing’ a large area of metal onto the glass, and then etching it off would be a more reliable technique than trying to deposit complex patterns directly to the glass in one go. Either way, though, it’s worth a try if you have a fiber laser.
Don’t have a fiber laser? Maybe you could build one.
2025-06-02 16:00:00
[It’s on my MIND] designed a clever BB blaster featuring a four-bar linkage that prints in a single piece and requires no additional hardware. The interesting part is how it turns a trigger pull into launching a 6 mm plastic BB. There is a spring, but it only acts as a trigger return and plays no part in launching the projectile. So how does it work?
The usual way something like this functions is with the trigger pulling back a striker of some kind, and putting it under tension in the process (usually with the help of a spring) then releasing it. As the striker flies forward, it smacks into a BB and launches it. We’ve seen print-in-place shooters that work this way, but that is not what is happening here.
With [It’s on my MIND]’s BB launcher, the trigger is a four-bar linkage that transforms a rearward pull of the trigger into a forward push of the striker against a BB that is gravity fed from a hopper. The tension comes from the BB’s forward motion being arrested by a physical detente as the striker pushes from behind. Once that tension passes a threshold, the BB pops past the detente and goes flying. Thanks to the mechanical advantage of the four-bar linkage, the trigger finger doesn’t need to do much work. The spring? It’s just there to reset the trigger by pushing it forward again after firing.
It’s a clever design that doesn’t require any additional hardware, and even prints in a single piece. Watch it in action in the video, embedded just below.
2025-06-02 13:00:00
The idea of staggered (or brick) layers in FDM prints has become very popular the past few years, with now nightly builds of OrcaSlicer featuring the ‘Stagger Perimeters’ option to automate the process, as demonstrated by [Stefan] in a recent CNC Kitchen video. See the relevant OrcaSlicer GitHub thread for the exact details, and to obtain a build with this feature. After installing, slice the model as normal, after enabling this new parameter in the ‘Strength’ tab.
In the video, [Stefan] first tries out a regular and staggered perimeter print without further adjustments. This perhaps surprisingly results in the staggered version breaking before the regular print, which [Stefan] deduces to be the result of increasing voids within the print. After increasing the extrusion rate to 110% to fill up said voids, this does indeed result in the staggered part showing a massive boost in strength.
What’s perhaps more telling is that a similar positive effect is observed when the flow is increased with the non-staggered part, albeit with the staggered part still showing more of a strength increase. This makes it obvious that just staggering layers isn’t enough, but that the flowrate and possibly other parameters have to be adjusted as well to fully realize the potential of brick layers. That said, it’s encouraging to see this moving forward despite questionable patent claims.
2025-06-02 10:00:00
If you need to weigh your pet, you’ll soon find that getting an animal to stand on a weighing machine to order is very difficult indeed. If the critter in question is a cat or a small dog you can weigh yourself both holding them and not holding them, and compute the difference. But in the case of a full size Bernese mountain dog, the hound is simply too big for that. Lateral thinking is required, and that’s how [Saren Tasciyan] came up with the idea of making a dog bed that’s also a weighing machine. When the mutt settles down, the weight can be read with ease. The bed itself is a relatively straightforward wooden frame, with load cells placed above rubber feet. The load cells in turn talk to an ESP8266 which has an LCD display to deliver the verdict. Dog weighed, without the drama.
This project is of course part of the Hackaday 2025 Pet Hacks contest, an arena in which any of the cool hacks you’ve made to enhance you and your pet’s life together can have an airing. Meanwhile this isn’t the first time this particular pooch has had a starring role; he’s sported a rather fetching barrel in a previous post.
2025-06-02 07:00:38
It appears that we’re approaching the HAL-9000 point on the AI hype curve with this report, which suggests that Anthropic’s new AI model is willing to exhibit some rather antisocial behavior to achieve its goals. According to a pre-release testing summary, Claude Opus 4 was fed some hypothetical company emails that suggested engineers were planning to replace the LLM with another product. This raised Claude’s hackles enough that the model mined the email stream for juicy personal details with which to blackmail the engineers, in an attempt to win a stay of execution. True, the salacious details of an extramarital affair were deliberately seeded into the email stream, and in most cases, it tried less extreme means to stay alive, such as cajoling senior leaders by email, but in at least 84% of the test runs, Claude eventually turned to blackmail to get its way. So we’ve got that to look forward to.
Also from the world of AI, at least tangentially, it now appears possible to doxx yourself just by making comments on YouTube videos. The open-source intelligence app is called YouTube Tools, and when provided with a user’s handle, it will develop a profile of the user based on their comments and some AI magic. We wanted to give it a try, but alas, it requires a paid subscription to use, and we’re not willing to go that far even for you, dear reader. But reports are that it can infer things like the general region in which the commenter lives and discern their cultural and social leanings. The author, LolArchiver, has a range of similar mining tools for other platforms along with reverse-lookup tools for phone and email addresses, all of which likely violate the terms of service in all kinds of ways. The accuracy of the profile is obviously going to depend greatly on how much material it has to work with, so in addition to the plenty of reasons there are to avoid reading YouTube comments, now there’s a solid reason to avoid writing them.
“Danger! Code Yellow aboard the International Space Station! All hands to emergency escape pods!” OK, maybe not, but as we teased a bit on this week’s podcast, there’s now a handy desktop app that allows you to keep track of the current level of urine in the ISS’s storage tanks. The delightfully named pISSStream, which is available only for the Apple ecosystem, taps into NASA’s telemetry stream (lol) and pulls out the current level in the tanks, because why the hell not? As unserious as the project is, it did raise an interesting discussion about how fluid levels are measured in space. So we’ll be diving into that topic (yuck) for an article soon. It’ll be our number one priority.
Looks like it’s time for another Pluto pity-party with the news of a new trans-Neptunian object that might just qualify as another dwarf planet for our solar system. Bloodlessly named 2017 OF201, the object has an extremely elongated orbit, reaching from just outside Pluto’s orbit at about 44 astronomical units at perihelion and stretching more than 1,600 AUs at aphelion, and takes 25,000 years to complete. It honestly looks more like the orbit of a comet, but with an estimated diameter of 700 km, it may join the nine other likely dwarf planets, if further observations reveal that it’s properly rounded. So not only has Pluto been demoted from legit planet, it’s now just one of potentially ten or more dwarf planets plugging around out in the deep dark. Poor Pluto.
And finally, we hope this one is a gag, but we fear that the story of a Redditor unaware that analog camera film needs to be developed rings alarmingly true. The mercifully unnamed noob recently acquired a Canon AE-1 — excellent choice; that was our first “real” camera back in the day — and ran a couple of rolls of Kodak ColorPlus 200 through it. All seemed to be going well, although we suspect the photographer reflexively pulled the camera away from their eye with each exposure to check the non-existent screen on the back of the camera; old habits die hard. But when one roll of the exposed film was fed through a 35-mm scanner, the Redditor was disappointed to see nothing. Someone offered the suggestion that developing the film might be a good idea, hopefully as gently as possible. Hats off for dipping a toe in the analog world, but the follow-through is just as important as the swing.
