flux

34 Articles

DIY Mechanical Flux Dispenser Syringe Has Fine Control

December 17, 2021 by 16 Comments

[Perinski]’s design for a mechanical flux dispenser uses some common hardware and a few 3D printed parts to create a syringe with fine control over just how much of the thick stuff gets deposited. The design is slick, and there’s a full parts list to accompany the printed pieces. [Perinski] even has some useful tips on how to most effectively get flux into 5 mL syringes without making a mess, which is a welcome bit of advice.

There is also a separate companion design for a magnetic syringe cap. Not only does it have an O-ring to keep things sealed and clean, but the tip of the cap has a magnet embedded into it, so that it can be stowed somewhere safe while the dispenser is in use, and doesn’t clutter the workspace.

This is all a very interesting departure from the design of most syringe dispensers for goopy materials, which tend to depend on some kind of pneumatic action. Even so, we’ve also seen that it’s possible to have a compact DIY pneumatic dispenser that doesn’t require a bulky compressor.

If you can’t quite figure out how the ergonomics of [Perinski]’s design are intended to work one-handed, you’re not alone. One holds the syringe in their hand, and turns the large dial in small increments with a thumb to control extrusion. [Perinski] demonstrates it close-up around the 4:50 mark, but if you have a few minutes it is worth watching the entire video, embedded below.

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Reviving Old Recipe For Faraday Wax Keeps Vacuum Experiments Going

May 29, 2021 by 24 Comments

Science today seems to be dominated by big budgets and exotics supplies and materials, the likes of which the home gamer has trouble procuring. But back in the day, science was once done very much by the seats of the pants, using whatever was available for the job. And as it turns out, some of the materials the old-timers used are actually still pretty useful.

An example of this is a homemade version of “Faraday Wax”, which [ChristofferB] is using for his high vacuum experiments. As you can imagine, getting a tight seal on fittings is critical to maintaining a vacuum, a job that’s usually left to expensive synthetic epoxy compounds. Realizing that a lot of scientific progress was made well before these compounds were commercially available, [ChristofferB] trolled through old scientific literature to find out how it used to be done.

This led to a recipe for “Faraday Wax”, first described by the great scientist himself in 1827. The ingredients seem a little archaic, but are actually pretty easy to source. Beeswax is easy to come by; the primary ingredient, “colophony”, is really just rosin, pretty much the same kind used as solder flux; and “Venetian red” is a natural pigment made from clay and iron oxide that can be had from art suppliers. Melted and blended together, [ChristofferB] poured it out onto wax paper to make thin strips that are easily melted onto joints in vacuum systems, and reports are that the stuff works well, even down to 10-7 mbar.

We love this one — it’s the perfect example of the hacker credo, which has been driving progress for centuries. It also reminds us of some of the work by [Simplifier], who looks for similar old-time recipes to push his work in DIY semiconductors and backyard inductors forward.

[David Gustafik] dropped us the tip on this one. Thanks!

Popping The Hood On The Flux Beamo Laser Cutter

June 22, 2020 by 27 Comments

While the K40 has brought affordable laser cutting to the masses, there’s no question that it took a lot of sacrifices to hit that sub-$400 price point. There’s a reason that we’ve seen so many upgrades and improvements made to the base model machine, but for the price it’s hard to complain. That being said, for users who don’t mind spending a bit more money for a more complete out-of-the-box experience, there are other options out there.

One of them is the beamo, from FLUX. [Frank Zhao] recently picked up one of these $1,900 USD laser cutters because he wasn’t thrilled with the compromises made on the K40. Specifically, he really liked the idea of the internal water cooling system. Oddly enough, something about using a garden hose and buckets of water to cool the laser seemed off-putting. Luckily for us, he’s got a technical eye and the free time necessary to do a teardown and objective analysis of his new toy.

The short version of the story is that [Frank] is not only happy with the results he’s getting, but finds the machine to be well designed and built. So if you’re looking for a rant, sorry. But what you will find is a methodical look at each subsystem of the beamo, complete with annotated pictures and the kind of technical details that Hackaday readers crave.

We especially like his attempts to identify parts which might be difficult to source in the future; it looks like the CO2 laser tube might be proprietary, but everything else looks fairly jellybean. That includes the Raspberry Pi 3B that’s running the show, and the off-the-shelf touch screen HDMI display used for the interface. [Frank] did note that FLUX was unwilling to give him the credentials to log into the Pi and poke around, but with direct access to the SD card, it’s not like that will stop anyone who wants to get in.

In a way, laser cutters are in a similar situation today to that desktop 3D printers were in a few years ago. The cheap ones cut so many corners that upgrades and fixes are almost a necessity, and building your own machine is often less expensive than buying a commercial offering with similar specs. While the beamo is still a bit too expensive for the average hobbyist, it’s good to see machines of this caliber are at least coming down out of the 5 figure range.

Cheap Alternative Solvents For PCB Cleaning

April 29, 2020 by 82 Comments

If you’re in the habit of using isopropyl alcohol to clean your PCBs after soldering, you probably have a nice big jug of the stuff stashed away. If you don’t, you’re probably out of luck, since the COVID-19 pandemic has pretty much cleared IPA out of the retail market. But don’t fret: depending on where you live, alternative PCB cleaning solutions may be as close as your nearest auto parts store.

[Steven]’s search for a cheaper and perhaps more readily available substitute for his usual dedicated flux cleaner lead him to try automotive brake cleaner on a few test boards. He suspected that they might contain acetone, which is prone to yield unfortunate results with solder resist and silkscreen on PCBs, so some tests were in order. The brand he tried was Normfest Bremsenreiniger MC-1, a German brand that according to its Safety Data Sheet contains only hydrocarbons like alkanes, butane, and propane. It did a fine job cleaning all but the crustiest rosin flux without collateral damage.

In the video below, [Steven] goes through a few more brands with similar results, and we were encouraged enough by his results to check brake cleaners made for the US market. Alas, almost all of the cheap and readily available aerosols have acetone as the principle ingredient, mixed in with methanol, ethanol, and assorted ingredients that together will probably make for a bad day. About the only US-sold brand without acetone that we could find was Keller-Heartt, which lists only naptha and ethanol on its SDS. There may be others, but make sure you test whatever you find.

Aerosol solvents aren’t the only way to clean a PCB, of course. Ultrasonic cleaners do a great job, and as [Steven] discovered, they’re generally safe for most components.

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Simple Demo Shows The Potential Of Magnetic Gears

April 13, 2020 by 27 Comments

We’ve probably all used gears in our projects at one time or another, and even if we’re not familiar with the engineering details, the principles of transmitting torque through meshed teeth are pretty easy to understand. Magnetic gears, though, are a little less intuitive, which is why we appreciated stumbling upon this magnetic gear drivetrain demonstration project.

[William Fraser]’s demo may be simple, but it’s a great introduction to magnetic gearing. The stator is a block of wood with twelve bolts to act as pole pieces, closely spaced in a circle around a shaft. Both ends of the shaft have rotors, one with eleven pairs of neodymium magnets arranged in a circle with alternating polarity, and a pinion on the other side of the stator with a single pair of magnets. When the pinion is spun, the magnetic flux across the pole pieces forces the rotor to revolve in the opposite direction at a 12:1 ratio.

Watching the video below, it would be easy to assume such an arrangement would only work for low torque applications, but [William] demonstrated that the system could take a significant load before clutching out. That could even be a feature for some applications. We’ve got an “Ask Hackaday” article on magnetic gears if you want to dive a little deeper and see what these interesting mechanisms are good for.

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How Safe Is That Ultrasonic Bath For Flux Removal?

December 5, 2019 by 30 Comments

How do you clean the residual flux off your boards? There are plenty of ways to go about the job, ranging from “why bother?” to the careful application of isopropyl alcohol to every joint with a cotton swab. It seems like more and more people are turning to ultrasonic cleaners to get the job done, though, and for good reason: just dunk your board and walk away while cavitation does the work for you.

But just how safe is it to sonically blast the flux off your boards? [SDG Electronics] wanted to know, so he ran some cleaning tests to get to the bottom of things. On the face of it, dunking a PCB in an aqueous cleaning solution seems ill-advised; after all, water and electricity famously don’t mix. But assuming all the nooks and crannies of a board can be dried out before power is applied, the cleaning solution itself should be of little concern. The main beef with ultrasonic cleaning seems to be with the acoustic energy coupling with mechanical systems on boards, such as crystal oscillators or micro-electrical-mechanical systems (MEMS) components, such as accelerometers or microphones. Such components could resonate with the ultrasonic waves and be blasted to bits internally.

To test this, [SDG Electronics] built a board with various potentially vulnerable components, including the popular 32.768-kHz crystal, cut for a frequency quite close to the cleaner’s fundamental. The video below goes into some detail on the before-and-after tests, but the short story is that nothing untoward happened to any of the test circuits. Granted, no components with openings as you might find on some MEMS microphones were tested, so be careful. After all, we know that ultrasound can deal damage, and if it can levitate tiny styrofoam balls, it might just do your circuit in.

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Fail Of The Week: How Not To Re-Reflow

October 10, 2019 by 30 Comments

There’s no question that surface-mount technology has been a game-changer for PCB design. It means easier automated component placement and soldering, and it’s a big reason why electronics have gotten so cheap. It’s not without problems, though, particularly when you have no choice but to include through-hole components on your SMT boards.

[James Clough] ran into this problem recently, and he tried to solve it by reflowing through-hole connectors onto assembled SMT boards. The boards are part of his electronic lead screw project, an accessory for lathes that makes threading operations easier and more flexible. We covered the proof-of-concept for the project; he’s come a long way since then and is almost ready to start offering the ELS for sale. The PCBs were partially assembled by the board vendor, leaving off a couple of through-hole connectors and the power jack. [James]’ thought was to run the boards back through his reflow oven to add the connectors, so he tried a few experiments first on the non-reflow rated connectors. The Phoenix-style connectors discolored and changed dimensionally after a trip through the oven, and the plastic on the pin headers loosened its grip on the pins. The female header socket and the power jack fared better, so he tried reflowing them, but it didn’t work out too well, at least for the headers. He blames poor heat conduction due to the lack of contact between the board and the reflow oven plate, and we agree; perhaps an aluminum block milled to fit snugly between the header sockets would help.

Hats off to [James] for trying to save his future customers a few steps on assembly, but it’s pretty clear there are no good shortcuts here. And we highly recommend the electronic leadscrew playlist to anyone interested in the convergence of machine tools and electronics.

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