Let’s Understand The Exothermic Welding Process

Exothermic Weld Process –

An Exothermic Weld has higher mechanical strength than other forms of weld, and excellent corrosion resistance.

The exothermic weld process is a simple, self- contained method of forming high quality electrical connections. The compact process requires no external power or heat source, making it completely portable. Connections are made inside a semi-permanent graphite mould using the high temperature reaction of powdered copper oxide and aluminium.

An exothermic Weld connections is actually a molecular bond formed between two metals such as copper/copper, copper/steel and steel/steel.

Copper oxide and aluminium are combined and ignited.

Exothermic Weld is a process that achieves the molecular binding among two or more metallic conductors by a chemical reaction. This molecular binding improves mechanical, electrical and anti-corrosion properties compared with any mechanical connection. exothermic weld is the best way to make permanent, reliable and high conductivity connections any installation requiring an earthing system.

Exothermic weld is often used to join copper conductors. The welding process joins two electrical conductors by use of superheated copper alloy. An Exothermic Reaction requires no external heat or current source. The reaction occurs between a copper thermite composition that heats the copper. The chemical reaction is aluminothermic, occurring between aluminum powder and copper oxides. The reaction reaches very high temperatures. Reactant powders and a spark is all that is needed for a high energy reaction.


The Process of Exothermic Weld is a method of making electrical connections of copper to copper or copper to steel in which no outside source of heat or power is required. In this process, a special weld material is placed into a high temperature resistant mold and ignited. The process of igniting the particles creates extremely high heat and molten metal (exothermic reaction) up to 1400 degree celsius, and produces a molten metal slag. This liquid copper metal flows into the weld cavity, filling any available space and completes the weld. The weld is then allowed to cool and solidify before it is removed from the mold. The mold is ready for the next weld after a brief cleaning with a brush. This entire process takes only seconds to complete.

Exothermic Weld connections produce a permanent connection, superior in performance to any known mechanical or pressure type surface-to-surface contact connector. Because the connection produced is a molecular bond, an exothermic welded connection will not loosen or increase in resistance over the lifetime of the installation.

FEATURES of Exothermic Weld

  • It has a superior electrical conductivity than the conductors themselves.
  • It does not corrode oxide or degrade with time and is resistant to galvanic coupling.
  • It is able to withstand repeated electrical discharges.
  • It never increases its resistance.
  • It has higher mechanical and squeezing resistance than the conductors themselves.
  • It offers a permanent welding and a low resistance connection, essential for achieving longwearing and trustworthy results in earthings
  • It guarantees the most common connections not only between copper cables but also for welding tapes and metallic pieces made of brass, stainless steel, and copper coated steel earth rods.

Advantages And Disadvantages Of Exothermic Weld :

Compared for some other forms of weld, exothermic bonds employ a greater mechanical toughness. The weld can be proof against corrosion. You simply won’t notice an increase in electrical excess weight despite repeated small signal pulses; your weld is highly firm. The procedure is more costly, however. The task requires replaceable moulds, is not easily repeatable, which enable it to be impeded by means of poor weather conditions if the work is done out of doors.

Exothermic weld may also be done far from others. That reduces dangers to employees. A igniter is used with widespread graphite molds or a palatable made drop within weld metal ink cartridge, semi-permanent graphite crucible pattern, and an ignition company that connects your container with a cord.


  1. Mould is usually good for 50 – 60 connections in field conditions.
  2. The equipment is fragile and should be handled carefully while in use.
  3. Cleaning of moulds should be done using appropriate brush / tool after the mould is reasonably cool after a weld process. Avoid hot mould cleaning.
  4. Cavity cleaning should be carefully done to avoid damages / chipping.
  5. On completion of task, mould should be well cleaned from inside and from outside using soft cloth. It should be properly wrapped in Bubble Plastic Packing while storing it.
  6. The moulds and the weld powder should always be stored in cool & dry places.
  7. All tools and accessories must be cleaned before storing to safe reuse.


  • Products shall be installed and used only as indicated in product instruction sheets.
  • Products must never be used for a purpose other than the purpose for which they were designed or in a manner that exceeds specified load ratings.
  • All instructions must be completely followed to ensure proper and safe installation and performance.
  • Improper installation, misuse, misapplication or other failure to comply with instructions and warnings may cause bad weld joint, property damage or even serious badly injuries.