Choose the Right Soldering Iron

Soldering Iron Basics

A female engineer using solder in her office to test and fix a circuit board.

Soldering guns and soldering irons are tools that are used to join metal parts by liquifying a low melting point metal alloy (solder) to form an electrical or mechanical bond. The low heating point allows work on delicate materials like circuit boards, audio equipment, musical instruments and crafts. There are 3 main types of soldering tools:

Soldering guns, a pistol-shaped tool that heats faster and is more powerful than a soldering iron.
Soldering irons, a lighter wand-style tool that is good for more detailed work.
Soldering torches, which use butane fuel to heat and melt solder.

Each of these can easily handle basic soldering tasks, but they can also handle specialized tasks.

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What Type of Soldering Tool Do I Need?

The type of soldering tool you need is largely dependent on what kind of work you are planning on doing.

A man using a soldering iron to attach wires to an audio speaker terminal.

Soldering Irons

Soldering irons are wand-shaped tools that use a heated tip to join metal pieces together. Irons are available in several different sizes. They are lighter in weight than a soldering gun, making them less difficult to work with over longer periods. For delicate work like electronics or jewelry, a small wand is the choice. For larger projects, a more powerful wand is necessary. Soldering irons are also in a constant-on state, making reheating unnecessary. You can also choose from a variety of tips for your specific need in completing the task.

While larger wands are more powerful, they are not the choice for heavy-duty work. Soldering irons run from 6 watts of power up to 175 watts, with most being at the lower end of the scale for lighter projects. A soldering gun, with more power available, are more suited for larger repairs.

Types of Soldering Irons:

Wand or pencil style soldering irons plug directly into a wall outlet and do not have temperature adjustments.
Soldering iron stations have a base, iron holder and soldering iron. The base features the adjustable temperature control for the wand.
Cordless irons are small for working in tight areas without having a cord interfering with your job.

A person using a soldering gun to solder parts on a circuit board.

Soldering Guns

Soldering guns feature more power than soldering irons, typically between 75 watts up to 300 watts for industrial use. The pistol shape provides more control in cramped work areas. Soldering guns use transformers to convert power to a low-voltage current to heat up the loop-shaped tip. This power supply can heat up the gun for use in just seconds. Depressing the trigger halfway will provide full wattage power, while pulling the trigger all the way will provide medium power heat. Most models also have LED lights that shine when the trigger is pulled for work in low-light spaces. Guns also have replaceable tips for heavy-duty soldering, smoothing and cutting. These copper wire tips will dissolve over time and must be kept clean to ensure a quality bond for the metals.

Soldering Torch

Soldering torches run on butane fuel and feature instant lighting and heat. The torch can produce heat up to 2500 degrees F, making it capable of melting metals like aluminum, silver and copper. Plumbers find torches a valuable tool when working with copper pipes, while jewelers use them in creating new pieces. These torches are also handy for other tasks, like melting pipes that may have frozen, caramelizing the sugar in a crème brulee, and adding smoke flavoring to craft cocktails.

How Do I Use a Soldering Iron?

Soldering is a relatively simple household task where heat is applied to two metal pieces and then solder is applied to bond them together. Think of it as gluing the metal pieces together with the liquefied metal. While it is an easy home repair, it can be tricky at first. Always practice your project before actually doing the soldering.

Instructions

Just as your soldering iron tip should be clean, your materials need to be clean also so they can accept the bonding agent. Flux is applied to remove oxidation and keep it from forming during the soldering process. Flux can be applied in several different ways, like paste, liquid and with solder that has a flux core. The core’s melting point is lower than solder, so it melts first while the solder melts around it.

Tinning your solder tip is simply coating the tip with a thin coating of solder. Doing this helps with the heat transfer between your materials and the solder tip. To tin the tip, melt a thin coat of solder by touching it directly to the heated iron tip. This is the only time solder should directly contact your iron.

Caution

During the actual solder process, do not touch the solder to the iron’s tip.

Grasp your soldering iron like you would hold a pencil to write with or hold your soldering gun. Place the tip on the materials to be soldered, heating them together. After 3-4 seconds of heating, remove the tip and apply solder to the heated parts. Next, touch the opposite connection point to heat it. Solder should be applied only until the connection points are covered. Remove the solder first, then take away the iron tip. The bonded area should remain steady while the solder cools.

Remember that the soldering iron tip is very hot. Use caution so as not to burn yourself or damage your surroundings with scorch marks by returning the iron to its holder or replacing the heat-resistant tip cover.

Cleaning the tip before and after each use will keep it working properly. Be sure to clean again with a damp sponge and apply a very light coat of flux to protect the tip when not in use.

Lead is an active ingredient in many solders. Always solder in a well-ventilated space and wash your hands after using solder and the iron.

Solder and Flux

A roll of Oatey solder, tin of flux, brush and cleaning cloth.

There are three main types of solder: lead-base, lead-free and flux-core. All of these are metal alloys that can contain lead, tin, silver, bismuth, indium and cadmium. Lead and tin are the most common elements used in solders that are used to solder electronics. In choosing a solder, it must have a lower melting point than your metals you want to join so that it melts first.

Like the name says, lead-free solders don’t contain any lead. This solder does have a higher melting point than ones that contain lead.

Flux-core solders help to remove oxidation during the soldering process, cleaning the metal in preparation for applying solder. It also aids in keeping the solder wet and manageable. For electronics, rosin is used as the core flux. For plumbing and other metal soldering, an acid core flux solder is preferred.

Flux on its own will clean the metal surfaces in preparation for soldering, much like primer does for paint. Along with cleaning, it also increases the electrical connectivity and can assist in the solder flow. The three main flux types are rosin, organic acid and inorganic acid.

What About the Different Tips for Soldering Irons and Guns?

If you have a soldering task, whether general use or specialty, there’s probably a select soldering iron tip designed for it. But for most household soldering jobs, there are four common tips that will help you complete them easily.

Conical tips, with a pointed tip, are good everyday tips that allow soldering from just about any angle.
Chisel tips, shaped like the pointed edge, are good for applying heat and solder to a broader area than the chisel point. For example, this tip is good for joining thicker electrical wires.
Bevel tips, with its broad face, are helpful in drag soldering, where solder is applied to the tip and then applied over a larger area.
Knife edge tips, with an angled tip, are used to fix and clean up solder joints.