Making nylon plastic from raw chemicals used to be a very common demo; depending where and when you grew up, you may well have done it in high school or even earlier. What’s not common is taking that nylon and doing something with it, like, say extruding it into filament to make a benchy. [Startup Chuck] shows us there might be a reason for that. (Video, embedded below.)

It starts out well enough: sebacoyl chloride and hexamethaline diamine mix up and do their polymerizing tango to make some nylon, just like we remember. (Some of us also got to play with mercury bare-handed; safety standards have changed and you’ll want to be very careful if you try this reaction at home). The string of nylon [Chuck] pulls from the beaker even looks a little bit like filament for a second, at least until it breaks and gets tossed into a blobby mess. We wonder if it would be possible to pull nylon directly into 1.75 mm filament with the proper technique, but quality control would be a big issue. Even if you could get a consistent diameter, there’d likely be too much solvent trapped inside to safely print.

Of course, melting the nylon with a blowtorch and trying to manually push the liquid through a die to create filament has its own quality control problems. That’s actually where this ends: no filament, and definitely no benchy. [Chuck] leaves the challenge open to anyone else who wants to take the crown. Perhaps one of you can show him how it’s done. We suspect it would be easiest to dry the homemade nylon and shred it into granules and only then extrude them, like was done with polypropylene in this mask-recycling project. Making filament from granules or pellets is something we’ve seen more than once over the years.

If you really want to make plastic from scratch, ordering monomers from Sigma-Aldrich might not cut it for ultimate bragging rights; other people are starting with pulling CO2 from the atmosphere.

Thanks to [Chaz] for the tip! Remember that the tips line isn’t just for your successes– anything interesting can find its home here.

Indycar Racing 2 was a good game, back in 1995; in some ways, it was the Crysis of the Clinton years, in that most mortals could not run it to its full potential when it was new. Still, that potential was surely fairly limited, as we’re talking about a DOS game from 30 years ago. Sure, it was limited– but limits are meant to be broken, and games are made to be modded. [TedMeat] has made a video showing the updates. (Embedded below.)

It turns out there was a 3D-accelerated version sold with the short-lived Rendition graphics cards. That version is what let the community upscale everything to the absurd resolutions our modern monitors are capable of. Goodbye SVGA, hello HD. Specifically, [sharangad] has created a wrapper to translate the Rendition API to modern hardware. It doesn’t sound like higher-res textures have been modded in, in which case this looks spectacular for graphics designed in 1995. It’s not the latest Forza, but for what it is, it impresses.

The second hack [TedMeat] discusses is a mod by [GPLaps] that pulls physics values from game memory to throw to a modern force-feedback wheel, and it shows just how good the physics was in 1995. You really can feel what’s going on– stopping a skid before it starts, for example. That’s normal these days, but for the kids playing with a keyboard in 1995, it would have been totally mind-blowing.

As tipster [Keith Olson] put it: “What can I say? Fans gonna fan!” — and we’re just as grateful for that fact as we are for the tipoff. If you’re in a fandom that’s hacked its way to keep old favourites alive, we’d love to hear about it: submit a tip.

Every Boy Scout or Girl Guide probably had the experience of building a simple solar oven: an insulated box, some aluminum foil, and plastic wrap, and voila! On warm, sunny, summer days, you can bake. On cloudy days, well, you need another plan. The redoubtable [Kris De Decker] and [Marie Verdeil] provide one, with this solar-electric oven over on LowTechMagazine.

Now, you might be wondering: what’s special here? Can’t I just plug a full electric range-oven into the inverter hooked to my Powerwall? Well, yes, Moneybags, you could — if you had a large enough solar setup to offset the storage and inverter losses, that is. But if you only have a few panels, you need to make every watt count. Indeed, this build was inspired by [Kris]’ earlier attempt to power his apartment with solar panels on his balcony. His electric oven is one of the things that stymied him at that time. (Not because cooking took too much energy, but because it took too much power for his tiny battery to supply at once.)

That’s why this oven’s element is DC, driven directly from the panel: there are no batteries, no inverter, and no unnecessary losses. The element is hand-made to match the solar setup, avoid an unnecessary electronic thermostat, and is sized to keep the oven from getting too hot. The oven itself is tiny, only large enough for a single casserole pan, but it does cover 90% of their cooking. A smaller oven is obviously going to need less power to heat up, but it also makes it practical to wrap it in oodles of insulation to reduce losses even further.

Indeed, between the 5 cm of insulation and thermal mass from the mortar-and-tile interior, when preheated by the specified 100 W panel, this oven can retain its cooking temperature well after sunset. Instead of needing a battery, the oven is the battery. It’s really quite elegant. That does require a certain mental adjustment as well: “cooking temperature” here is only 120°C (248°F), about a hundred F less than most recipes in our cookbooks. This hack is almost like a solar-powered cross between an oven and a slow cooker.

It’s undeniably efficient, but we can only imagine it would take some getting used to. Of course, so does running a solar-powered website, and LowTechMagazine has kept that going since 2018.

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.

The fact that there exist in our world flat rocks that make lightning when you point them at the sun is one of the most unappreciated bits of wizardry in this modern age. As hackers, we love all this of techno-wizardry–but some of us abhor paying full price for it. Like cars, one way to get a great discount is to buy used. [Backyard Solar Project] helped a friend analyze some 14-year-old panels to see just how they’d held up over the years, and it was actually better than we might have expected.

The big polycrystalline panels were rated at 235 W when new, and they got 6 of them for the low, low price of “get this junk off my property”. Big panels are a bit of a pain to move, but that’s still a great deal. Especially considering that after cleaning they averaged 180 W, a capacity factor of 77%. Before cleaning 14 years worth of accumulated grime cost about eight watts, on average, an argument for cleaning your panels. Under the same lighting conditions, the modern panel (rated to 200 W) was giving 82% of rated output.

That implies that after 14 years, the panels are still at about 94% of their original factory output, assuming the factory wasn’t being overoptimistic about the numbers to begin with. Still, assuming you can trust the marketing, a half a percent power drop per year isn’t too bad. It’s also believable, since the US National Renewably Energy Laboratory (yes, they have one) has done tests that put that better than the average of 0.75 %/yr. Of course the average American solar panel lives in a hotter climate than [Backyard Solar Project], which helps explain the slower degradation.

Now, we’re not your Dad or your accountant, so we’re not going to tell you if used solar panels are worth the effort. On the one hand, they still work, but on the other hand, the density is quite a bit lower. Just look at that sleek, modern 200 W panel next to the old 235 W unit. If you’re area-limited, you might want to spring for new, or at least the more energy-dense monocrystalline panels that have become standard the last 5 years or so, which aren’t likely to be given away just yet. On the gripping hand, free is free, and most of us are much more constrained by budget than by area. If nothing else, you might have a fence to stick old panels against; the vertical orientation is surprisingly effective at higher latitudes.

The idea of gamifying all the things might have died down now that the current hype is shoving AI into all the things — but you’ve probably never seen it quite like EmuDevz, a game in which you develop an 8-bit emulator by [Rodrigo Alfonso].

There’s a lot of learning you’ll have to do along the way, about programming and how retro systems work, including diving into 6502 assembly code. Why 6502? Well, the emulator you’re working on (it’s partially-written at the start of the game; you need only debug and finish the job) is for a fantasy system called the NEEES “an antique game console released in 1983”. It’s the NEEES and not NES for two reasons. One, Nintendo has lawyers and they really, really know how to use them. Two, by creating a fantasy console that is not-quite-a-Famicom, the goalposts for EmuDevz can be moved a bit closer in.

The in-game emulator will handle most NES behavior, assuming you do your part correctly. A selection of homebrew NES games is included with EmuDevz, and they all run fine. A neat touch is giving you the ROMs for offline use as rewards when you get them running correctly. If some edge cases and exotic behaviours get left behind in the interests of simplicity, just remember– it’s not a NES, it’s a NEEES, and who can say? Perhaps this simplified system is exactly how it worked in the alternate universe where this game is set.

Aside from the invaluable assembly code, the work is done in JavaScript, which might not be everybody’s cup of tea. On the other hand, the whole thing is open-source (MIT license for the code, CC for the content) so if you really, really hate JS but love the idea of a learning game like this, you could fork to the language of your choice and learn even more.

Regardless of the language used, we like this model and think the “game where you learn to make games” is a great educational model for programming skills that ought to be used more often. For an idea of what it looks like, check out the trailer below.

Thanks to [Rodrigo Alfonso] for the tip. If you’ve got a great gamified learning tool — or any other cool hack, for that matter — the tips line is fun and rewarding, even if we haven’t tried to gamify it.

Tubes! Not only is the internet a series of them, many projects in the physical world are, too. If you’re building anything from a bicycle to a race cart to and aeroplane, you might find yourself notching and welding metal tubes together. That notching part can be a real time-suck. [Jornt] from HOMEMADE MADNESS (it’s so mad you have to shout the channel name, apparently) thought so when he came up with this 3-axis CNC tube notcher.

If you haven’t worked with chrome-molly or other metal tubing, you may be forgiven for wondering what the big deal is, but it’s pretty simple: to get a solid weld, you need the tubes to meet. Round tubes don’t really want to do that, as a general rule. Imagine the simple case of a T-junction: the base of the T will only meet the crosspiece in a couple of discreet points. To get a solid joint, you have to cut the profile of the crosspiece from the end of the base. Easy enough for a single T, but for all the joins in all the angles of a space-frame? Yeah, some technological assistance would not go amiss.

Which is where [Jornt]’s project comes in. A cheap plasma cutter sits on one axis, to cut the tubes as they move under it. The second axis spins the tube, which is firmly gripped by urethane casters with a neat cam arrangement. The third axis slides the tube back and forth, allowing arbitarily long frame members to be cut, despite the very compact build of the actual machine. It also allows multiple frame members to be cut from a single long length of tubing, reducing setup time and speeding up the overall workflow.

The project is unfortunately not open source– instead [Jornt] is selling plans, which is something we’re seeing more and more of these days. (Some might say that open source hardware is dead, but that’s overstating things.) It sucks, but we understand that hackers do need money to eat, and the warm fuzzy feeling you get with a GPL license doesn’t contain many calories. Luckily [Jornt] has put plenty of info into his build video; if you watch the whole thing, you’ll have a good idea of the whole design. You will quite possibly walk away with enough of an idea to re-engineer the device for yourself, but [Jornt] is probably assuming you value your time enough that if you want the machine, you’ll still pay for the plans.

This isn’t the first tubing cutter we’ve featured, though the last build was built into a C (It wasn’t open-source either; maybe it’s a metalworking thing.)NC table, rather than being stand-alone on the bench like this one.

Thanks to [Shotgun Moose] for the tip! Unlike tubing, you can just toss your projects into the line, no complex notching needed.