The 9 Best Soldering Irons
Special Honors
McMaster-Carr Irons If you don’t have a ton of experience in the application areas, you’d be surprised by the vast number of ways in which a soldering iron can be used. For example, McMaster-Carr offers models with fixed temperatures, adjustable temperatures, fine tips, instant-heat capabilities, and several additional variations. mcmaster.com
Editor's Notes
February 11, 2021:
There are a few different kinds of soldering irons to choose from. The NOEVSBIG 908DB represents the simplest type, which just plugs into the wall directly, and the Vastar AC222, just without digital control and with a bunch of accessories and a toolbox. The Master Appliance Ultratorch UT-100SiK is the top butane-powered option and its less expensive relatives are also of very high quality, although they aren't quite as powerful or long-running. The X-Tronic 3020-XTS offers an impressive value for such a full-featured option, and it doesn't disappoint in terms of build quality or performance, either. The Hakko FX-888D is known to perform on an even higher level, and though it costs more than most, would be the best choice for someone who plans on using it full time.
June 10, 2019:
There was a new version of the Weller Analog available, but we noted a substantial drop-off in quality with the most recent model. A short lifespan, inaccurate temperature readings, and a weak pen have all frustrated users. Rather than include a poor model in the list, we eliminated this option entirely. Also removed the X-Tronic Digital, as many reports indicate that this unit often dies within the first year of ownership.
The Vastar 60W had also become outdated, so we swapped in the new version of this model — the Vastar AC222. It’s an affordable option that comes with plenty of accessories, which makes it a nice choice for someone who likes to handle light-duty projects around the house without hiring a professional. For more substantial applications, we’d recommend a heavy-duty model instead.
We added a butane-powered tool in the Dremel 2000-01, which impresses users with its fast heat-up process and high-quality carrying case. We also noted the array of practical tips that come with it. The HoLife Black is the other new item — its accurate temperature controls are helpful for detailed work, and its sturdy base features a sponge tray for soaking up excess solder.
Just Say No To Lead Pipes
It took off in the third millennium B.C.E. with the introduction of tin alloys such as bronze.
There aren't many modern building or manufacturing techniques that have been in use for several thousand years. Soldering — the joining of two items using a filler metal — is used for some of today's most important products (circuit boards) just like it was used for the most important items in ancient history (weapons and treasure). It combines the disciplines of metalworking and metallurgy, and has a wide range of applications.
Its earliest known use was in ancient Egypt, well-known today for the extensive adornment of palaces and tombs with jewelry and fixtures made of precious metals and gemstones. It took off in the third millennium B.C.E. with the introduction of tin alloys such as bronze. Techniques gradually advanced over the next few ages, arguably reaching their pre-industrial peak with the construction of the Roman aqueducts. This legendary water-delivery system was assembled of huge pipes whose seams were purported to withstand pressures well over 100 PSI.
Throughout history, craftsmen used simple heat sources like coals or open flames to heat items and melt solder, but beginning in the 20th century the suddenly popular phenomenon of electricity made its way into the practice, ultimately resulting in Ernst Sachs producing the first widely known commercial soldering iron in 1921. Despite being over a century old, the soldering iron's basic design hasn't changed much over the years.
Ironing Out The Details
Today's most common varieties are quite simple, just like those early versions. They consist of a heated tip, an insulated handle, and a power cable. The heating element is often a typical resistive-type heater, made of a high-resistance alloy (usually involving mostly chrome and nickel) that sheds excess electricity as heat. Basic models operate at a fixed temperature, so be sure to get the right wattage for the jobs you plan to do. High-precision jobs like printed circuit boards call for smaller irons that deliver effective heat levels without harming the board, while larger jobs like AC connections need a stronger heat source simply to melt the increased amount of solder across a larger joint.
Both combustion and catalyzation are possible thanks to the relatively high number of low-energy bonds present in hydrocarbon molecules.
Alternately, there are plenty of models that offer variable temperature using one of a few different techniques. Some operate like a standard dimmer switch, either by redirecting a portion of the current into a different resistor, or switching the AC sine wave off and on again many times per second. Fancier models include bi-metal thermocouples that monitor temperature falloff from heat dissipation and reheat the tip accordingly, and some of the best options feature remarkably accurate digital readouts that are especially useful if you work with varying kinds of metal.
There are two different types of hydrocarbon-fueled irons. One style combines an actual pressurized torch (i.e. a blowtorch) with a heating plate that conducts energy to the tip. The other uses a method called catalytic heating, whereby an electrical signal kicks off a chain reaction of molecules breaking apart and expelling energy as excess heat. Both combustion and catalyzation are possible thanks to the relatively high number of low-energy bonds present in hydrocarbon molecules. Gas-powered models are usually so designed in order to be portable.
I Now Pronounce You Wire And Post
In its simplest form, soldering is a relatively straightforward process that almost anyone can learn with just a little dedication. First and foremost are preparation and safety. Avoid jewelry and loose-fitting clothing, and make sure your hair is out of the way. It's not a bad idea to wear protective gloves as long as they're thermally protected (i.e. they won't melt to your skin), because there's a lot of heat involved in soldering, and sometimes mildly toxic metals. Thankfully, the industry is moving away from lead-based materials. Also, be certain to provide adequate ventilation, as the gases associated with this apparently harmless task can actually cause notable lung damage. Finally, ensure that all surfaces as well as the tip of your soldering iron are thoroughly cleaned, as a dirty tip is difficult to control, and can cause heat spikes and damage to sensitive electronics.
The ideal heat level for each project will vary depending on the materials you're joining, the type of current they'll be handling, and what the solder itself is made of.
To make the magic happen, the opposing surfaces and the tip of the iron are lightly coated in solder, a process called tinning. This initial coating ensures that the molten material makes it all the way into the tiniest divots and crevices in the two items. It's always important to apply the heat to the items rather than the solder itself,
Almost as important to the solder material itself is a substance called flux. Common solder adheres well to bare metal, but it does not stick well to the various oxides that start to form as you heat up metal in our oxygen-rich environment. Flux can serve a number of specific functions in the soldering process, but it primarily acts as an oxide reducer, keeping all concerned surfaces clean and bare while you're in the act of joining them. Different jobs like refrigerator repair and Raspberry Pi customization call for different types of solder, some of which have hollow cores filled with the appropriate flux, which eliminates the need for an additional step.
The ideal heat level for each project will vary depending on the materials you're joining, the type of current they'll be handling, and what the solder itself is made of. It's imperative to use the right combination of alloys, fluxes, and temperatures, as too little heat results in failed connections, while too much heat encourages oxides as well as sub-standard alloys called intermetallics to form, which will eventually degrade the joint's integrity.
Whether you're a seasoned electrician or an amateur DIY enthusiast, soldering is a skill worth picking up. It's useful for repairing small electronics and light fixtures around the house, and it's absolutely necessary for today's clever Internet-Of-Things developers. Beyond the different levels of electronics maintenance, soldering and its higher-temperature counterpart, brazing, are effective and expressive means of sculpture than can turn mere scrap into works of art. Mastering this ancient technique takes time, but when attacked with gusto, soldering can provide satisfaction, respect for materials, and lots of fixed lamps.