Why Can’t I 3D Print With Rubber?

December 31, 2025 by Jenny List 54 Comments

A friend of mine and I both have a similar project in mind, the manufacture of custom footwear with our hackerspace’s shiny new multi-material 3D printer. It seems like a match made in heaven, a machine that can seamlessly integrate components made with widely differing materials into a complex three-dimensional structure. As is so often the case though, there are limits to what can be done with the tool in hand, and here I’ve met one of them.

I can’t get a good range of footwear for my significantly oversized feet, and I want a set of extra grippy soles for a particular sporting application. For that the best material is a rubber, yet the types of rubber that are best for the job can unfortunately not be 3D printed. In understanding why that is the case I’ve followed a fascinating path which has taught me stuff about 3D printing that I certainly didn’t know.

The extruder unit from a Prusa Mini 3D printer — Newton strikes back, and I can’t force rubber through this thing.

A friend of mine from way back is a petrochemist, so I asked him about the melting points of various rubbers to see if I could find an appropriate filament His answer, predictably, was that it’s not that simple, because rubbers don’t behave in the same way as the polymers I am used to. With a conventional 3D printer filament, as the polymer is fed into the extruder and heated up, it turns to liquid and flows out of the nozzle to the print. It ‘s then hot enough to fuse with the layer below as it solidifies, which is how our 3D prints retain their shape. This property is where we get the term “plastic” from, which loosely means “Able to be moulded”.

My problem is that rubber doesn’t behave that way. As any casual glance at a motor vehicle will tell you, rubber can be moulded, but it doesn’t neatly liquefy and flow in the way my PLA or PET does. It’s a non-Newtonian fluid, a term which I was familiar with from such things as non-drip paint, tomato ketchup, or oobleck, but had never as an electronic engineer directly encountered in something I am working on. Continue reading “Why Can’t I 3D Print With Rubber?” →

How Wind Nearly Took Down Boulder NTP

December 29, 2025 by Fenix Guthrie 26 Comments

NTP is one of the most interesting and important, but all too forgotten, protocols that makes the internet tick. Accurate clock synchronization is required for everything ranging from cryptography to business and science. NTP is closely tied around a handful of atomic clocks, some in orbit on GPS satellites, and some in laboratories. So the near-failure of one such atomic clock sparked a rather large, and nerdy, internet debate.

On December 17, 2025, the Colorado front range experience a massive wind storm. The National Center for Atmospheric Reassure in Boulder recorded gusts in excess of 100 mph (about 85 knots or 160 kph). This storm was a real doozy, but gusts this strong are not unheard of in Boulder either. That is no small reason the National Renewable Energy Laboratory (now the National Laboratory of the Rockies) has a wind turbine testing facility in the neighborhood.

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Surviving The RAM Apocalypse With Software Optimizations

December 23, 2025 by Maya Posch 96 Comments

To the surprise of almost nobody, the unprecedented build-out of datacenters and the equipping of them with servers for so-called ‘AI’ has led to a massive shortage of certain components. With random access memory (RAM) being so far the most heavily affected and with storage in the form of HDDs and SSDs not far behind, this has led many to ask the question of how we will survive the coming months, years, decades, or however-long the current AI bubble will last.

One thing is already certain, and that is that we will have to make our current computer systems last longer, and forego simply tossing in more sticks of RAM in favor of doing more with less. This is easy to imagine for those of us who remember running a full-blown Windows desktop system on a sub-GHz x86 system with less than a GB of RAM, but might require some adjustment for everyone else.

In short, what can us software developers do differently to make a hundred MB of RAM stretch further, and make a GB of storage space look positively spacious again?

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Catching Those Old Busses

December 17, 2025 by Al Williams 30 Comments

The PC has had its fair share of bus slots. What started with the ISA bus has culminated, so far, in PCI Express slots, M.2 slots, and a few other mechanisms to connect devices to your computer internally. But if the 8-bit ISA card is the first bus you can remember, you are missing out. There were practically as many bus slots in computers as there were computers. Perhaps the most famous bus in early home computers was the Altair 8800’s bus, retroactively termed the S-100 bus, but that wasn’t the oldest standard.

There are more buses than we can cover in a single post, but to narrow it down, we’ll assume a bus is a standard that allows uniform cards to plug into the system in some meaningful way. A typical bus will provide power and access to the computer’s data bus, or at least to its I/O system. Some bus connectors also allow access to the computer’s memory. In a way, the term is overloaded. Not all buses are created equal. Since we are talking about old bus connectors, we’ll exclude new-fangled high speed serial buses, for the most part.

Tradeoffs

There are several trade-offs to consider when designing a bus. For example, it is tempting to provide regulated power via the bus connector. However, that also may limit the amount of power-hungry electronics you can put on a card and — even worse — on all the cards at one time. That’s why the S-100 bus, for example, provided unregulated power and expected each card to regulate it.

On the other hand, later buses, such as VME, will typically have regulated power supplies available. Switching power supplies were a big driver of this. Providing, for example, 100 W of 5 V power using a linear power supply was a headache and wasteful. With a switching power supply, you can easily and efficiently deliver regulated power on demand.

Some bus standards provide access to just the CPU’s I/O space. Others allow adding memory, and, of course, some processors only allow memory-mapped I/O. Depending on the CPU and the complexity of the bus, cards may be able to interrupt the processor or engage in direct memory access independent of the CPU.

In addition to power, there are several things that tend to differentiate traditional parallel buses. Of course, power is one of them, as well as the number of bits available for data or addresses. Many bus structures are synchronous. They operate at a fixed speed, and in general, devices need to keep up. This is simple, but it can impose tight requirements on devices.

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Thorium-Metal Alloys And Radioactive Jet Engines

December 16, 2025 by Maya Posch 36 Comments

Although metal alloys is not among the most exciting topics for most people, the moment you add the word ‘radioactive’, it does tend to get their attention. So too with the once fairly common Mag-Thor alloys that combine magnesium with thorium, along with other elements, including zinc and aluminium. Its primary use is in aerospace engineering, as these alloys provide useful properties such as heat resistance, high strength and creep resistance that are very welcome in e.g. jet engines.

Most commonly found in the thorium-232 isotope form, there are no stable forms of this element. That said, Th-232 has a half-life of about 14 billion years, making it only very weakly radioactive. Like uranium-238 and uranium-235 it has the unique property of not having stable isotopes and yet still being abundantly around since the formation of the Earth. Thorium is about three times as abundant as uranium and thus rather hard to avoid contact with.

This raises the question of whether thorium alloys are such a big deal, and whether they justify removing something like historical artefacts from museums due to radiation risks, as has happened on a few occasions.

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A Brief History Of The Spreadsheet

December 15, 2025 by Al Williams 63 Comments

We noted that Excel turned 40 this year. That makes it seem old, and today, if you say “spreadsheet,” there’s a good chance you are talking about an Excel spreadsheet, and if not, at least a program that can read and produce Excel-compatible sheets. But we remember a time when there was no Excel. But there were still spreadsheets. How far back do they go? Continue reading “A Brief History Of The Spreadsheet” →

Review: Cherry G84-4100 Keyboard

December 12, 2025 by Jenny List 45 Comments

The choice of a good keyboard is something which consumes a lot of time for many Hackaday readers, judging by the number of custom input device projects which make it to these pages. I live by my keyboard as a writer, but I have to admit that I’ve never joined in on the special keyboard front; for me it’s been a peripheral rather than an obsession. But I’m hard on keyboards, I type enough that I wear them out. For the last five years my Hackaday articles have come via a USB Thinkpad keyboard complete with the little red stick pointing device, but its keys have started parting company with their switches so it’s time for a replacement.

I Don’t Want The Blackpool Illuminations

A picture of the Blackpool illuminations at night against a dark sky. — Is it a gamer’s keyboard, or the Blackpool seafront at night? I can’t tell any more. Mark S Jobling, Public domain.

For a non keyboard savant peering over the edge, this can be a confusing choice. There’s much obsessing about different types of mechanical switch, and for some reason I can’t quite fathom, an unreasonable number of LEDs.

I don’t want my keyboard to look like the Blackpool Illuminations (translation for Americans: Las Vegas strip), I just want to type on the damn thing. More to the point, many of these “special” keyboards carry prices out of proportion to their utility, and it’s hard to escape the feeling that like the thousand quid stereo the spotty kid puts in his Opel Corsa, you’re being asked to pay just for bragging rights.

Narrowing down my needs then, I don’t need any gimmicks, I just need a small footprint keyboard that’s mechanically robust enough to survive years of my bashing out Hackaday articles on it. I’m prepared to pay good money for that.

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