A soldering iron is a tool which is designed to be used in soldering. Soldering is classically used to attach two pieces of metal to create a joint, although plastics can be soldered as well. Soldering irons provide a controlled source of heat which can be used to manipulate the materials used in the soldering process to achieve the desired goal of a smooth, clean joint. Soldering is easy enough to do that it is regularly taught in high school electronics classes.
In soldering, a highly ductile metal alloy known as solder is melted, fusing to the metal which is going to be joined. When the solder cools, a firm joint is created. In desoldering, the joint is heated to break the bonds and remove the solder, as may be done when something needs to be adjusted or reset. In both cases, a soldering iron is used to control the process.
