Exothermic welding makes strong and low resistant electrical connections of various metals like; copper to copper, copper to steel and steel to steel. Without an external heat or power source.
The weld metal powder, consisting of powdered aluminium and copper oxide. The powder is poured into a graphite mould (as shown right) followed by the ignition powder. Nothing more than a spark is required to ignite the powder.
The heat from the resultant exothermic reaction produces moulten copper and aluminium oxide slag.
In a matter of seconds the molten copper melts the metal disc and flows down the tap hole and over the conductors in the weld chamber, melting them and welding them into a solid mass.