Soldering iron: design and function

In many cases, there are uncertainties about the required wattage at the soldering iron for certain tasks. This is related to the fact that too little is known about the structure and operation of soldering iron. Both are explained in detail in our contribution.

Types of soldering iron

First, you have to differentiate between different types of soldering iron:

  • the soldering gun
  • the simple, unregulated soldering iron
  • Lötnadeln
  • temperature-controlled soldering stations

All soldering irons described here are only suitable for soft soldering, but not for brazing. Externally heated gas soldering irons are also not taken into account here.


The soldering gun is a classic home improvement tool. It works differently than an electric soldering iron. Here current flows through the tip, which is a kind of heating coil.

Within a few seconds, the tip heats up due to electrical resistance and serves as a soldering tip. In order to accelerate the heating even further, high currents are used here at low voltages, in the device therefore a suitable transformer is installed to generate such a current.

Electric soldering iron and soldering pins

In the electric soldering iron, the soldering tip (usually made of copper) is heated either from the inside or from the outside. The heating element is the classic soldering iron usually in the region of the head. Otherwise, only the top (usually replaceable) and a handle are required.

In a temperature-controlled soldering station in the immediate vicinity of the tip nor a temperature sensor. It measures the existing temperature at the top and returns it to the soldering station, which then adjusts accordingly.

The temperature stabilization of the unregulated soldering iron ("Magnastat") can be done either via a simple heating coil or via an electromechanical temperature control. The heating coil as a temperature sensor is also used by the temperature-controlled pistons of soldering stations.


Solder needles work in principle the same as the classic electric soldering iron, they are only much smaller and thinner. Soldering needles are used mainly for soldering very small components, very fine wires and for repair work.


A very important part of the soldering iron is the tip. Usually, soldering tips are made of copper, because this metal guarantees a particularly good thermal conductivity.

Copper tips are very soon starting to scale and must therefore always be cleaned and reworked with a file. This can be saved with so-called "Dauerlötspitzen". They are provided with a coating that does not need to be reworked (and may not).

Tips & Tricks

For soldering work, always use a soldering tip of the appropriate size - and of course the correct wattage at the soldering iron, or a soldering station.

Video Board: Dremel Versatip Gas Soldering Torch Demo & Review in HD