Soldering Iron Cauterization

Medical hacks are not for the weak of stomach, so read further at your own risk. [Todd Harrison] shows you how to remove a stubborn skin wart using a good ol’ soldering iron, and a fair endurance for pain. After all, cauterization is a well known and documented medical procedure. If you have the stomach for this, read on, or better, check out his 9 minute video after the break. If there are kids around, turn down the volume between 1:40 to 2:20.

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USB Soldering Iron is Surprisingly Capable

We know what you’re thinking. There’s no way an 8 watt USB-powered soldering iron could be worth the $5 it commands on eBay. That’s what [BigClive] thought too, so he bought one, put the iron through a test and teardown, and changed his mind. Can he convince you too?

Right up front, [BigClive] finds that the iron is probably not suitable for some jobs. Aside its obvious unsuitability for connections that take a lot of heat, there’s the problem of leakage current when used with a wall-wart USB power supply. The business end of the iron ends up getting enough AC leak through the capacitors of the power supply to potentially damage MOSFETs and the like. Then again, if you’re handy to an AC outlet, wouldn’t you just use a Hakko? Seems like the iron is best powered by a USB battery pack, and [BigClive] was able to solder some surprisingly beefy connections that way. The teardown and analysis reveal a circuit that looks like it came right out of a [Forrest M. Mims III] book. We won’t spoil the surprise for you – just watch the video below.

While not truly cordless like this USB-rechargeable iron, we’d say that for the price, this is a pretty capable iron for certain use cases. Has anyone else tried one of these? Chime in on the comments and let us know what you think.

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Hacklet 99 – Soldering Tools

If there is one tool every hardware hacker needs, it’s a good soldering setup. Soldering irons, heat guns, reflow ovens and the like make up the tools of the trade for building electronic circuits. Spend enough time working with a tool, and you’ll find a way to improve it. It’s no surprise that hackers, makers, and engineers have been hacking their soldering tools for decades. This week’s Hacklet features some of the best soldering tool projects on!

hakkoWe start with  [Kuro] a Hakko 907 based Soldering Station. Hakko 907 and 936 soldering station clones from the Far East are available all over the internet. While the heaters work, none of them have very good temperature controllers. [Kuro] turned a problem into a project by building his own soldering station. These irons are rated for 24 V. 24 volt power supplies are not very common, but it’s easy to find old 19 volt supplies from discarded laptops. [Kuro] found that the lower voltage works just fine. An Arduino nano controls the show, with user output displayed on a 2 line LCD. The finished controller works better than the original, and probably would give a real Hakko model a run for its money.

reflowNext up is [Sukasa] with Reflow Oven. When MakerSpace Nanaimo needed a reflow oven, [Sukasa] jumped in with this design. The idea was to create an oven that looked unmodified – just think of it as the toaster oven of the future, or the reflow oven of today. A Netduino plus 2 is the main controller. User information is displayed on a color TFT LCD. This oven is even internet connected, with an internally hosted web page and JSON data feed. The Netduino controls two beefy Solid State Relays (SSRs). The SSRs handle the dirty work of switching the oven’s heating elements. Two fans keep air moving to avoid hot spots. Precision temperature sensing is achieved through a pair of Adafruit MAX31855 breakout boards reading thermocouples.

plateNext we have [Jaromir Sukuba] with Soldering preheat plate. When soldering surface mount components, like QFN or BGA parts, it helps to pre-heat the whole board. There are commercial products to do this using hot air and other techniques, but it really comes down to making a hotplate. [Jaromir] figured he could do a pretty good job at this, so he built his own with a 3mm aluminum plate. Heat comes from 6 resistors in TO-220 cases. A Microchip PIC18 monitors a thermocouple and keeps things from getting too hot. For power, [Jaromir] had the same idea as [Kuro] did, and used a 19V power brick from an old laptop.

gooseFinally we have [Alex Rich] with Locking ball and socket gooseneck system. [Alex] came up with the Stickvise, so it’s fitting that he comes up with an awesome upgrade for it. We’ve all fought with “helping hands” while soldering. You never get them at quite the right angle. This system fixes that with a simple ball and gooseneck setup. [Alex] saw a similar design and printed it out. While it worked, the pieces popped apart too easily. [Alex] redesigned the system, adding a threaded locking ring. These new goosenecks stay put, holding your work exactly where you want it.

If you want to see more soldering tool projects, check out our brand new soldering tools list! If I missed your project, don’t be shy! Just drop me a message on That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of!

Recursive Soldering Iron Hacking

We’ve all done it. You’re walking out the door or maybe you’ve even gotten on the road when the question hits, “Did I leave the [coffee pot | stove | hair curler | soldering iron ] on?” [Daniel Johnson’s] problem was even worse. He couldn’t tell if his Hakko-936 soldering iron was off because the LED indicator wasn’t always on. Instead it flashed. He fixed that problem and along the way hacked his battery powered soldering iron since he was out of batteries. Now that’s perseverance.

Hacked Soldering Iron to Hack Soldering Iron
Soldering Iron Hack Recursion

The Hakko’s LED turned on whenever the power turned on to heat the tip. That was about every 5 seconds once the tip was hot. But just as a watched pot never boils, a watched LED never seems to flash. After determining the LED was driven by a comparator he decide to unsolder it as part of his hack. He wisely decided using the Hakko on itself was not a good idea so reached for the battery-powered portable iron, which was sadly battery-free. Undaunted, he wired the portable to a power supply and when 4.5 volts didn’t melt the solder cranked it up to 6 volts.

Back to the Hakko, he replaced the red LED with a RBG LED but used only the red and green leads. The green was tied to the 24v power supply through a hefty 47k ohm resistor, and the red was tied to the comparator. A little masking tape to hold things in place and provide insulation finished the job. Now when the Hakko is on the green LED is lit and the red LED shows the heating cycle. Quite clever.

Homemade Soldering Station Does it Better

Soldering stations are probably one of the most important tools in the hacker’s arsenal. Problem is — good ones are expensive, and sometimes the only difference between being okay at soldering versus being great at it, is the quality of the tool you’re using! Which is why [Albert] and [Matthias] decided to make their very own home-made Weller clone.

Since the most important part of the soldering iron is a good tip, they’re using a needle from Weller — they just need to be able to control it. They designed a 3D printed housing (source files here) for a small 1.8″ LCD screen, an Arduino Pro Mini and a MOSFET shield, and the 12v 8A power supply they chose. There are only two controls — on/off, and a potentiometer for adjusting the temperature.

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A DIY Mobile Soldering Iron

Cordless soldering irons are, as a rule, terrible. A few months ago, you could pick up a cordless soldering iron from Radio Shack that was powered by AAA batteries. You can guess how well those worked. There are butane-fueled soldering irons out there that will heat up, but then you’re left without the requisite degree of temperature control.

[Xavier] didn’t want to compromise on a mobile soldering iron, so he made a desktop version portable. His mobile temperature controlled soldering iron uses the same electronics that are found in inexpensive Hakko clones, and is powered by a LiPo battery.

The soldering station controller comes directly from eBay, and a DC/DC boost converter accepts just about any DC power supply – including an XT60 connector for LiPo cells. A standard Hakko 907 iron plugs into the front, and a laser cut MDF enclosure makes everything look great. There were a few modifications to the soldering station controller that involved moving the buttons and temperature display, but this build really is as simple as wiring a few modules together.

With an off-the-shelf LiPo battery, the iron heats up fast, and it doesn’t have a long extension cord to trip over. With the right adapter, [Xavier] can use this soldering station directly from a car’s cigarette power port, a great feature that will be welcomed by anyone who has ever worked on the wiring in a car.

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Hacking Amazing Soldering Features into the Already Great Weller WMRP

Weller, the German soldering tools manufacturer, has a nice range of micro soldering irons (pencils) designated as the WMRP series. These are 12V, 40 W or 55W units with a 3 second heat up time, and allow quick tip exchange without needing any tools. [FlyGlas] built a neat soldering station / controller for the WMRP series based around an ATMega microcontroller running Arduino.

It’s packed with most of the features you see in a professional rig.

  • low offset op amp for soldering tip temperature measurement with type c thermocouple
  • cold junction compensation using the PTC (KTY82-210) included in the WMRP soldering pencil
  • input voltage measurement
  • soldering pencil current measurement
  • recognizing if the soldering pencil rests in the stand (–> standby)
  • 3 buttons to save and recall temperature values
  • rotary encoder to set soldering temperature
  • illuminated 16×2 character LCD module
  • USB for debugging and firmware update
  • 4mm safety socket for +12V power input and a protective earth socket for connection to ESD protection

WMRP_controller_02A PWM signal from the microcontroller controls the load current using a MOSFET. Load current is measured using a Hall Effect-Based Linear Current Sensor – ACS712. The corresponding linear output voltage is buffered and slightly amplified using AD8552 zero drift, single supply, RRIO Dual Op Amp before being sent to the microcontroller ADC input. To ensure ADC measurements are accurate and stable, a low noise precision voltage reference – ADR392 is used. Another precision resistive voltage divider allows input voltage measurement. The supply input has over-current and reverse voltage protection. A set of buttons and a rotary encoder are connected to the microcontroller to allow settings and adjustments. An analog section measures the thermocouple voltage from the soldering pencil as well as the stand-by switch status. The handle has an embedded reed switch that is activated by a magnet in the support stand which puts it into stand-by mode. Another analog section performs cold junction compensation using the PTC sensor within the soldering pencil.

The Git repo contains the initial Arduino code which is still a work in progress. While the hardware source files are not available, the repo does have the pdf’s, gerbers and BOM list, if you want to take a shot at building it. Check a demo video after the break. Thanks [Martin] for sending in the tip.

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