The soldering iron is used to heat the soldering point and melt soft solder in order to connect components to printed circuit boards, to join wires and strands together or to attach them to pins of plugs and sockets, or to connect mechanical parts (e.g. metal sheets). Heat is transferred by mechanical contact between the hot soldering tip and the solder joint, whereby the thermal bridge is created via the liquid solder. Soldering with a soldering iron is a soft soldering process. Soft soldering is characterized by the fact that the melting point of the filler metal is below about 450 °C, whereas silver soldering and hard soldering use higher temperatures, usually requiring a flame or carbon arc torch to achieve melting of the filler metal. Soft solder alloys are generally alloys with liquidus temperatures below 450 °C.

Different types of soldering irons have evolved over time. They range from unregulated manual soldering irons to microprocessor-controlled, temperature-regulated soldering stations with varying power and different types of soldering tips. There are gas and electrically heated soldering irons.

Overview