Want a Temperature-Controlled Cordless Soldering Iron? Here’s How to Make One particular


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Image: Randi Klett

When I to start with figured out to solder, I did so using a cheap iron, not realizing how atrocious this kind of matters are. It wasn’t right up until a number of many years afterwards that I acquired a temperature-controlled soldering station. These use thermal feedback to keep the suggestion at a established temperature, and I shortly uncovered that excellent solder joints are effortless to make when you have good machines. I have experienced that pretty very same Weller WTCPN soldering station for nearly 4 decades now, acquiring forsaken non-temperature-managed irons completely.

This stance on soldering irons did, on the other hand, put me in a quandary not too long ago when I began to discover the possibilities for cordless soldering irons. Cordless irons are necessary for those people situations when you require to solder a thing and there is no ability outlet available. But I could not discover a cordless iron for sale that had temperature manage. So I figured I’d construct myself just one.

My fondness for my devoted Weller soldering station dictated the initially structure criterion—it had to provide the exact good quality temperature control—and also recommended a system to attain that intention: Weller’s Magnastat procedure [PDF]. Allow me clarify. Weller extensive in the past devised a clever way to present temperature opinions and regulate without having applying any electronics. It’s based on the physics of ferromagnetic materials, which get rid of their magnetism when heated over a specified temperature, known as the Curie level. Weller’s Magnastat procedure utilizes three magnetic elements in close proximity to the idea: two within a typically open up switch, the other designed into the idea by itself. The factors inside the switch (one particular movable) have a really substantial Curie issue, whilst the one in the idea has a Curie place equal to the desired soldering temperature.

When the iron is cold, a movable long-lasting magnet in the swap is drawn to the ferromagnetic suggestion, closing the swap and sending power to the heating element. The suggestion then gets hot. When the magnet in the tip exceeds its Curie temperature and loses its magnetism, the movable magnet shifts towards the set 1 in the switch, leading to the switch to open and shutting off electric power. When the idea cools down below its Curie issue, it is magnetized by advantage of the industry from the nearby movable magnet, which is then drawn to it, closing the change and reapplying ability. Presto—temperature opinions!

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Picture: David Schneider

Solder On: Two sets of rechargeable batteries within a Maglite case gives energy to heat a soldering iron tip.

For my cordless iron, I duplicated this method by purchasing some Magnastat substitute sections from Mouser Electronics: the magnetic swap, the heating aspect, a tip, and the barrel employed to hold the idea on. The challenge was to source the idea with 24 volts or so. My Weller soldering station has a enormous transformer that operates off a wall socket, while my cordless iron would certainly need to have to run off batteries.

You could effortlessly choose an entire Magnastat soldering iron and electricity it with a pair of 12-volt lead-acid batteries. But I was aiming for a little something a lot more transportable. That is when it transpired to me to offer my cordless iron into a different piece of machines I’m fond of: a Maglite flashlight.

Maglites are made of properly machined and anodized aluminum with attractive knurling. I acquired a non-LED, two-D-mobile product at a close by components retail store and took it aside, which needed purchasing a alternative swap for the flashlight so I could get the required Torx wrench.

Of system, two D batteries would provide only a meager 3 volts. But this flashlight presents enough house for 6 14500 lithium-ion cells, which alongside one another can offer about 22 volts. Soon after substantial digging, I identified a supply for a a few-cell holder for AA batteries that puts them in sequence and is about the sizing of a D battery. So all I needed to do was to obtain two these kinds of holders and outfit them with 14500 lithium-ion rechargeable batteries, which are about the dimensions of AA cells.

The issues below is that I preferred to use protected lithium-ion cells. These have a minimal bit of circuitry designed in that handles issues like overcharging or limited circuits, which can induce lithium-ion batteries to do unpleasant points, like bursting into flame. These cells are inclined to be a minor extended since the protection circuit awkwardly adds to their length. (Flashlight enthusiasts, it seems, run into this problem a whole lot.) My resolution was to obtain 6 Xtar cells, which are a minimal shorter than most 14500s. I was satisfied I did that for the reason that they match into my holders beautifully.

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Picture: David Schneider

Hacking Even though Unplugged: The tip’s temperature is regulated by a magnetic switch. This cordless design and style allows me make substantial-high-quality joins in the area.

These 800-milliampere-hour cells are nominally rated for only 1.6 amperes, but which is the most they’d will need to offer for all but possibly a couple of tens of seconds in a cost cycle. And a quite helpful on the internet reviewer confirmed that their security circuits never kick in right until just about 3 A, which is larger than my soldering iron would ever require.

Generally packaging a Do it yourself gizmo is the toughest part. But marrying the Weller Magnastat technologies with a Maglite flashlight proved remarkably simple. It required drilling just five holes into two aluminum disks procured on eBay for US $1 each. The disks acquire the location of the very clear plastic lens of the flashlight and present a strong and heat-insensitive area on to which to mount the heating component. All that was left was to make 4 solder connections (to the flashlight contacts and a 5-A fuse), hook up the Magnastat parts with wire nuts, and place the disassembled flashlight again alongside one another. I turned it on, and soon made a perfect solder joint with my new cordless iron.

This short article seems in the November 2017 print situation as “A Do-it-yourself Soldering Iron for Tinkering on the Go.”

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