“Exothermic” is a chemical term used to describe a reaction that produces heat.

Exothermic welding, also known as “thermit welding” or “aluminothermic welding” is a welding process for permanently joining materials (usually copper conductors) that employs an exothermic reaction. The exothermic reaction requires no external heat or a power source. All that is required is a spark to initiate the reaction.


The exothermic reaction occurs between copper oxide and aluminium powder (contained within the weld metal) creating molten super-heated copper and an aluminium oxide slag. When an ignition spark comes into contact with the weld metal, it causes an exothermic reaction within the weld metal, melting and separating the metals. The aluminium rises to the top of the connection creating a slag leaving the molten copper to flow around the joint, creating the weld.

Exothermic reaction

The KingsWeld exothermic connection is a permanent, maintenance-free weld that will not loosen overtime or deteriorate with age. The connections’ current carrying capability is equal to or greater than that of the conductors being joined. In other words, there is no increase in resistance in an exothermically welded connection, unlike in most pressure type (bolt/crimp) connections.

Throughout the world, exothermic welding has been shown to be the best choice where safety, reliability, current carrying capacity and longevity are critical.


  1. The current carrying capacity of the connection is greater than or equal to that of the conductor
  2. Has a lower electrical resistance than a mechanical connection
  3. Does not deteriorate with age
  4. Does not loosen over time
  5. Can withstand repeated high current surges without deterioration
  6. Does not require an external power source
  7. Used to weld copper, copper alloys, copper bonded steel, various steel alloys, including stainless steel
  8. Quick and easy to install
  9. Exceptional corrosion resistance due a very high copper content (97%+)
  10. Fusion temperature is in excess of 2000°C forming a molecular bond

This adds up to a superior connection when compared to mechanical or pressure type (crimp) connectors.

The KingsWeld exothermic connection is the best choice, especially in safety critical environments where reliability, longevity and current carrying capacity are paramount.