A soldering iron is a hand tool consisting of an insulated handle and a heated metal tip, or bit, designed to melt solder to join two metal workpieces together. Heat is supplied by the iron to the tip, causing the solder, a low-melting-point metal alloy, to flow into the joint between the components. Once the solder cools, it solidifies, creating a permanent, conductive, and mechanically strong bond. Soldering irons are widely used in electronics, auto repair, plumbing, and jewelry making.