Soldering Like It’s 205 BC

Did you ever stop to think how unlikely the discovery of soldering is? It’s hard to imagine what sequence of events led to it; after all, metals heated to just the right temperature while applying an alloy of lead and tin in the right proportions in the presence of a proper fluxing agent doesn’t seem like something that would happen by accident.

Luckily, [Chris] at Clickspring is currently in the business of recreating the tools and technologies that would have been used in ancient times, and he’s made a wonderful video on precision soft soldering the old-fashioned way. The video below is part of a side series he’s been working on while he builds a replica of the Antikythera mechanism, that curious analog astronomical computer of antiquity. Many parts in the mechanism were soldered, and [Chris] explores plausible methods using tools and materials known to have been available at the time the mechanism was constructed (reported by different historians as any time between 205 BC and 70 BC or so). His irons are forged copper blocks, his heat source is a charcoal fire, and his solder is a 60:40 mix of lead and tin, just as we use today. He vividly demonstrates how important both surface prep and flux are, and shows both active and passive fluxes. He settled on rosin for the final joints, which turned out silky smooth and perfect; we suspect it took quite a bit of practice to get the technique down, but as always, [Chris] makes it look easy.

If you’d like to dig a bit deeper into modern techniques, we’ve covered the physics of solder and fluxes in some depth. And if you need more of those sweet, sweet Clickspring videos, we’ve got you covered there as well.

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Fail of the Week: Solid State Relay Fails Spectacularly

A lot of times these days, it seems like we hackers are a little like kids in a candy store. With so many cool devices available for pennies at the click of a mouse, it’s temptingly easy to order first and ask questions about quality later. Most of the time that works out just fine, with the main risk of sourcing a dodgy component being a ruined afternoon of hacking when a part fails.

The stakes are much higher when you’re connecting your project to the house mains, though, as [Mattias Wandel] recently learned when the solid-state relay controlling his water heater failed, with nearly tragic results. With aplomb that defies the fact that he just discovered that he nearly burned his house down, [Mattias] tours the scene of the crime and delivers a postmortem of the victim, a Fotek SSR-25DA. It appears that he mounted it well and gave it a decent heatsink, but the thing immolated itself just the same. The only remnant of the relay’s PCB left intact was the triac mounted to the rear plate. [Mattias] suspects the PCB traces heated up when he returned from vacation and the water heater it was controlling came on; with a tank full of cold water, both elements were needed and enough current was drawn to melt the solder build-up on the high-voltage traces. With the solder gone, the traces cooked off, and the rest is history. It’s a scary scenario that’s worth looking at if you’ve got any SSRs controlling loads anywhere near their rated limit.

The morals of the story: buy quality components and test them if possible; when in doubt, derate; and make sure a flaming component can’t light anything else on fire. And you’ll want to review the basics of fire protection while you’re at it.

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Benchtop Fume Extractor Cuts the Cord, Clears the Air

What good is safety gear that isn’t used because it’s annoying and gets in the way of getting the job at hand completed? None, really, and the solder fume extractor is one item that never seems to live in harmony with your workspace. They’re often noisy, they obstruct your vision, and a power cord draped across your bench is a sure way to ruin your soldering zen.

To fix those problems, [Nate] has built a nice battery powered solder fume extractor that’s so low profile and so quiet, you won’t mind sharing a bench with it. Based on a standard 80-mm case fan, the extractor has a built-in 18650 battery for power and a USB charging port. There are nice little features, like a speed control and a low-battery indicator. The fan mounts to a pair of custom PCBs, which form the feet for the fan. [Nate] claims to have run the fan for 12 hours straight on battery before needing a charge, and that it’s so quiet he needs to add a power indicator to the next version. Also making an appearance in rev 2 will be a carbon filter to catch the fumes, but as [Nate] notes, better to spread them around for now than let them go directly up his nose.

Are you in the hacking arts for the long haul? Let’s hope so. If you are, make sure you’re up on the basics of mitigating inhalation hazards.

VFD Puts the Suck Back into Desoldering Station

A dedicated desoldering station is a fantastic tool if you’re in the business of harvesting components from old gear. Having heat and suction in a single tool is far more convenient than futzing with spring-loaded solder suckers or braid, but only as long as the suction in the desoldering tool has a little oomph behind it. So if the suction on your solder sucker is starting to suck, this simple VFD can help restore performance.

Luckily for [Mr. Carlson], his Hakko 470 desoldering station is equipped with an AC induction motor, so it’s a perfect candidate for a variable frequency drive to boost performance. He decided to build a simple VFD that boosts the frequency from 60-Hz mains to about 90-Hz, thereby jacking the motor speed up by 50%. The VFD is just a TL494 PWM chip gating the primary coil of a power transformer through a MOSFET. Duty cycle and frequency are set by trimmers, and the whole thing is housed in an old chassis attached to the Hakko via an anachronistic socket and plug from the vacuum tube days. That’s a nice touch, though, because the Hakko can be returned to stock operation by a simple bridging plug, and the video below shows the marked difference in motor speed both with and without the VFD plugged in.

We’ve marveled at [Mr. Carlson]’s instrument packed lab before and watched his insider’s tour of a vintage radio transmitter. Here’s hoping we get to see more of his hopped-up solder sucker in action soon.

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Think You Know Everything About Soldering?

[Joshua] has frequent discussions about his soldering techniques with viewers of his YouTube channel. He finally decided to interview [Randy Rubinstein] who is the president of SRA Soldering. In nearly an hour, they talk about everything from solder alloys to proper temperature. They also talk about lead exposure, flux cleaning, and lead-free solder.

They also talk about strategies for rework with lead-free and using special solder for removing SMD components. Honestly, although the first frame of the video says “your solder sucks,” we didn’t really find any earth-shattering revelations about something everyone’s doing wrong. We did, however, find a lot of good advice and some interesting details about things like the uses for different solder alloys.

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Hackaday Prize Entry: OLED Displays For Soldering Iron Tips

Having soldered one end of a wire to a switch, you move on to the next step in your hack, soldering the other end of the wire to the more temperature sensitive pin 11 on the 6847 video chip. You set the soldering pen’s target temperature to something lower. You position the end of a tinned wire just so, with the solder held between the ring and pinky fingers of the same hand. You stare hard at the pin while you still know which one it is. Luckily this soldering pen has a display in the handle, close enough for you to glance at it quickly and see that the target temperature has been reached. You solder the wire in place.

The previous hack was one I did back in 1982 to my TRS-80 color computer but alas, there was no display in the soldering pen’s handle. I was just too early for the sweet soldering pen that [vlk] is making, and has entered into the 2017 Hackaday Prize.  It’s powered by a LiPo battery and can go from 25 to 400℃ in 5 seconds. The handle contains the electronics, including an STM32F031, and we’re impressed with how small he’s managed to get it all. Two buttons provide control and an OLED display simultaneously shows what looks like two target temperatures, the current temperature, voltages, battery charge level, and status. And if you want to make your own, his page even includes the schematics. Watch how easy it is to use in the videos below the break.

While [vlk]’s soldering pen has all the precision and ease of use you’d want, check out what is probably the simplest approach to soldering iron temperature control we’ve seen here. Or you could go for something in between, this one that’s also powered by LiPo batteries but has the display in a small laser cut box.

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One Soldering Controller To Rule Them All

If your favourite programming language is solder, they you’ve surely worked your way through a bunch of irons and controllers over your hacker existence. It’s also likely you couldn’t pick one single favourite and ended up with a bunch of them crowding your desk. It would be handy to have one controller to rule them all. That’s just what [sparkybg] set out to do by building his Really Universal Soldering Controller. His intent was to design a controller capable of driving any kind of low voltage soldering iron which used either an in-line or separate temperature sensor (either thermocouple or resistive PTC).

This project has really caught on. [sparkybg] announced his build about two years back and since then many others have started posting details of their own Unisolder 5.2 builds. [zed65] built the version seen to the right and [SZ64] assembled the boards shown at the top of this article.

The controller has been proven to work successfully with Iron handles from Hakko, Pace, JBC, Weller, Ersa, as well as several Chinese makes. Getting the controller to identify one of the supported 625 types of iron profiles consists of connecting two close tolerance resistors across the relevant pins on the 9-pin shell connector. This is a brilliant solution to help identify a large variety of different types of irons with simple hardware. In the unlikely situation where you have a really vague, unsupported model, then creating your own custom profile is quite straightforward. The design is highly discrete with an all analog front end and a PIC32 doing all the digital heavy lifting.

To get an idea of the complexity of his task, here is what [sparkybg] needs to do:

“I have around 200 microseconds to stop the power, wait for the TC voltage to come to its real value, connect the amplifier to this voltage, wait for the amplifier to set its output to what I want to read, take the measurement from the ADC, disconnect the amplifier from the TC, run the PID, and eventually turn the power back on. The millivolts to temperature calculation is done using polynomial with 10 members. It does this calculation using 32bit mantissa floating point numbers and completes it in around 20 microseconds. The whole wave shaping, temperature calculation, PID and so on is completed in around 50-60 microseconds. RMS current, voltage and power calculations are done in around 100 microseconds. All this is done between the half periods of the mains voltage, where the voltage is less than around 3 volts.”

The forum is already over 800 posts deep, but you can start by grabbing the all important schematic PDF’s, Gerbers, BoM and firmware files conveniently linked in the first post to build your own Unisolder5.2 controller. This Universal Controller is a follow up to his earlier project for a Hakko T12/T15 specific controller which gave him a lot of insight in to designing the universal version.

[sparkybg] has posted several videos showing the UniSolder5.2 controlling several types of Irons. In the video after the break, he demonstrates it controlling a Weller WSP80.

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