Soldering is the process of forming a joint between two surfaces by heating a filler material (also known as solder wire or solder) at 840°F or lower until it flows between two surfaces and then cools to form a bond. Soldering irons are handheld tools used to melt solder. Soldering accessories include tips, heating elements, handpieces, and iron stands and cradles. Soldering and desoldering stations are machines that allow operators to control and adjust heat settings of soldering and desoldering irons. Desoldering equipment is used to remove solder from workpieces. Soldering and desoldering tip cleaners remove flux residue from tips and prevent oxidation. Soldering iron testers and thermometers measure tip temperature, iron temperature, and leak voltage to help ensure optimal temperatures are maintained.