How does a soldering iron work?


When working with metal or electrical components, there will inevitably come a time (or many times) when you need to join two things together. A soldering iron is a popular device commonly used for this task.

As helpful and powerful as a soldering iron is, if not used correctly, you may not see the best results. Additionally, a misused soldering iron can become a safety risk. So what you need to know about how this tool works to stay safe and work productively?

Components of your soldering iron

A soldering iron works by passing heat through a thermally conductive material to melt solder – often tin and lead – used to connect two items, such as wires, together. The way this process works with your specific soldering iron depends on the model you use and how it’s powered. Here are some common components found in soldering irons and their functions:

Protective cap

A plastic sheath keeps your soldering iron safe from bumps and dings when not in use. Always keep your soldering iron in the cap when not in use and make sure all parts of the iron have completely cooled before replacing the cap.


Many soldering irons are powered by butane gas, which can be inserted into the soldering iron itself. There’s usually a gas nozzle at the end of the iron that’s opposite the tip.

Gas control lever

The gas control lever helps you regulate the temperature of the soldering tip. You can also adjust the gas control to accommodate various conditions, such as by increasing the gas level when working in a colder environment.

Knurled nut

The knurled nut keeps the soldering iron’s two halves secured together. Make sure this is tight before using your soldering iron.

Tip housing

The tip housing secures the tip firmly in the soldering iron. This is also where the butane heats the tip, so the housing also includes ignition vents.

Ignition vent

Located on the tip housing, the ignition vent lets air in to support the flame which heats the tip. When the vent is closed, the flame is extinguished.

Hot air exhaust opening

The hot air exhaust opening is located on the tip and lets heated air escape the tool. Make sure to not touch this part and position it upward when at rest so as to not burn any materials directly below the opening.

Soldering tip

Finally, the soldering tip is the part that comes in contact with and melts the solder material. There are various designs of tips that are tailored to different types of projects. Always change tips before you begin using the soldering iron or after it has completely cooled. To change tips, loosen the knurled nut, slide out the current tip, drop in the one you want and tighten the nut.

The soldering irons at Master Appliance, such as the Ultratorch and the Econoiron, are reliable, versatile and easy to use. Shop our selection to find the right tool for you.

masterheat Written by: