High Quality Content by WIKIPEDIA articles! Exothermic welding, also known as exothermic bonding, thermite welding (TW), and thermit welding, is a welding process for joining two electrical conductors, that employs superheated copper alloy to permanently join the conductors. The process employs an exothermic reaction of a copper thermite composition to heat the copper, and requires no external source of heat or current. The chemical reaction that produces the heat is an aluminothermic reaction between aluminium powder and a mixture of copper oxides (copper(II) oxide and copper(I) oxide), with chemical formula: