Imagine you’re a commando, doing some big secret mission on the continent in the midst of World War II. You need to hook up some wires to your explosive charges, and time is of the essence. Do you bust out the trusty Weller and see if those petulant Axis chaps will let you plug it in somewhere? No! You use a pyrotechnic self-soldering sleeve, as [Our Own Devices] explains.
Like so many British inventions during the war, the sleeves really are ingenious. They were developed by the Special Operation Executive, an organization charged with sabotage and subversion operations in then-occupied Europe.
The soldering sleeves were designed to make electrical connections between detonators and firing wires for explosives. The sleeves consist of a copper tube through which wires to be joined are fed, with a lump of solder in the middle. The assembly is covered in pyrotechnic material with a safety match-style starter chemical dosed on top. Using the sleeves is simple. First, two stripped wires are fed into either end of the copper tube. The starter the sleeve is then ignited using the box, just like striking a match. The pyrotechnic material then gets red hot, melting the solder and making the connection.
If someone in 2023 has ever had much call to use turpentine, chances are good it was something to do with paint or other wood finishes, like varnish. Natural turpentine is the traditional solvent of choice for oil paints, which have decreased in popularity with the rise of easy-to-clean polymer-based paints and coating. Oh sure, there are still those who prefer oil paint, especially for trim work — it lays up so nice — but by and large, turpentine seems like a relic from days gone by, like goose grease and castor oil.
It wasn’t always so, though. Turpentine used to be a very big deal indeed, as shown by this circa 1940 documentary on the turpentine harvesting and processing industry. Even then it was only a shadow of its former glory, when it was a vital part of a globe-spanning naval empire and a material of the utmost strategic importance. “Suwanee Pine” shows the methods used in the southern United States, where fast-growing pines offer up a resinous organic gloop in response to wounds in their bark. The process shown looks a lot like the harvesting process for natural latex, with slanting gashes or “catfaces” carved into the trunks of young trees, forming channels to guide the exudate down into a clay collecting cup.
Homebrew reflow projects generally follow a pretty simple formula: find a thrift shop toaster oven or hot plate, add a microcontroller and a means to turn the heating element on and off, and close the loop with a thermistor. Add a little code and you’re melting solder paste. Sometimes, though, a ground-up design works better, like this scalable reflow plate with all the bells and whistles.
Now, we don’t mean to hate on the many great reflow projects we’ve seen, of course. But [Michael Benn]’s build is pretty slick. The business end uses 400-watt positive temperature coefficient (PTC) heating elements from Amazon controlled by solid-state relays, although we have to note that we couldn’t find the equivalent parts on the Amazon US site, so that might be a problem. [Michael] also included mechanical temperature cutoffs for each plate, an essential safety feature in case of thermal runaway. The plates are mounted at the top of a 3D-printed case, which also has an angled enclosure for a two-color OLED display and a rotary encoder.
The software runs on an ESP32 and supports multiple temperature profiles for different solder pastes. The software also supports different profiles on the two plates, and even allows for physical expansion to a maximum of four heating plates, or even just a single plate if that’s what you need. The video below shows it going through its paces along with the final results. There’s also a video showing the internals if that’s more your style
We appreciate the fit and finish here, as well as the attention to safety. Can’t find those heating elements for your build? You might have to lose your appetite for waffles.
The warm and rather stinky heart of any hacker’s lair is the soldering station, where the PCB meets the metal (solder). A good soldering station lets you get on with the business of building stuff without worrying about piffling details like temperature and remembering to turn the thing off. The AxxSolder is a neat design from [AxxAxx] that fulfills these criteria, as it includes full PID control of the iron and an auto sleep feature. It will run from any DC power source from 9 to 26 Volts, so you can run it off your bench power supply and have one less thing to plug in. There is even a portable version for those on-the-go hackathons.
For a lot of us, soldering has become so ingrained that it’s muscle memory. We know exactly when the iron is hot enough, how long to leave the tip in contact with the joint to heat it up, and exactly where to dab in the solder to get it to flow. When you’re well-practiced it can be a beautiful thing, but for those who don’t do it frequently, soldering can be frustrating indeed.
The “Solder Sustainer” looks like it just might be aimed at solving that problem, as well as a few others. It comes to us from [RoboticWorx], and while it looks a little like the love child of a MIG welder and a tattoo machine, it’s got a lot going for it. The idea is to make soldering a one-handed task by combining the soldering iron and a solder wire feeder into one compact package. The solder feeder is very reminiscent of a filament extruder on a 3D printer, using a stepper to drive spring-loaded pinch wheels, which forces the solder down a curved 3D-printed tube that directs it toward the tip. The pancake stepper is driven by an ESP32, which also supports the touch sensor that lets you advance the solder. The whole thing can be powered off a USB-C power supply, or using the onboard USB charger that can be connected in line with the soldering iron supply.
The video below shows Solder Sustainer in use. Yes, we know — some of those joints look a little iffy. But that seems to have more to do with technique than with the automatic solder feed. And really, in situations where you’ve previously wished for a third hand while soldering, this would probably be just the thing.
The Solder Sustainer is an entry in the “Gearing Up” round of the 2023 Hackaday Prize. If you’ve got an idea for a tool, jig, fixture, or instrument that makes hacking easier, we want to know about it. But you’d better hurry — the round ends on August 8.
Want a better way to feed solder, but want to do it on the quick and cheap? Well [ptkrf] has a solution for you in an old instructables post we stumbled upon recently. You might have, or can inexpensively buy, a mechanical pencil which has the feeder button on the side rather than on top, as usual. With the pencil in hand, [ptkrf] shows you the simple procedure for modifying the pencil into a solder feeder. You might need to experiment with different size pencils and solders to get a perfect match. Common mechanical pencils come in sizes to accommodate 0.5, 0.7, and 0.9 mm leads, but there are bigger and smaller ones available. Perhaps one of those really large drafting lead holders could be repurposed as a solder dispenser for the bigger jobs.
We discussed a 3D printed solder feeder a few days ago, but if you don’t have one, this may be a good way to go. Thanks to [iliis] for sending in this tip.
The intended use-case is for busy work like soldering long pin headers. The one-handed device allows solder to be continually fed while the other hand uses the soldering iron. It solves a long-running problem for [mulcmu], after their experiments with techniques inspired by TIG welding came to nought.
The design uses a pen-like form factor. A 3D-printed hollow tube has a wire ferrule inserted in the end, which serves as the tip of the device through which solder is fed. The tube has a cutaway, which allows the user to feed solder through using an easy motion of the thumb. The solder itself is fed from a spool in a regular bench top holder. If more slack is required in the solder feed, one simply pins the solder down in the device and tugs to draw more out.
If you find yourself regularly soldering repetitive jobs by hand, this could be a gamechanger for you. Those working in through-hole would be perhaps best served by this device. Meanwhile, if you’ve got nifty tool hacks of your own to share, don’t hesitate to let us know!