Solder wire is a thin, metallic wire typically composed of a solder alloy, which is a combination of various metals such as tin, lead, silver, or other elements. Solder wire is used in soldering processes to join together two or more metal surfaces by melting the solder and allowing it to flow into the joint, creating a metallurgical bond upon cooling. Solder wire comes in various diameters and compositions to suit different soldering applications