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 Exothermic Weld 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.

EXOTHERMIC WELD PROCESS

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.

 

Process for Exothermic Weld is as follows:

STEP - 1:  
Always wear protective safety glasses and gloves while working with exothermic welding products. 

STEP - 2:
Gather all the proper material and equipment/accessories for the type of connection you are making. The typical Weld system requires a graphite mold, handle clamp, welding material, natural bristle brush for mold cleaning, wire brush for cleaning/preparing conductors, flint igniter, and propane torch. Check to ensure the graphite mold is not worn or broken, which could cause leakage of molten weld metal.

STEP - 3:  
Slide the handle clamp into the pre-drilled holes with the proper orientation for the thumbscrews.
 

STEP - 4:  
Tighten the clamp thumbscrews onto the mould. 
 

STEP - 5:  
Close the grips to tightly lock the mold. Make adjustments to tighten/loosen the handle clamp.
 

STEP - 6:  
The material to be welded (cable, rod, tape) must be clean and dry using the brush included in the set of accessories. Thus the oxide layer and superficial impurity is eliminated.  Given that the graphite mould also absorbs moisture, this should be removed by preheating with a gas welding torch to avoid a porous welding. After the first welding is done, it is not necessary to re-heat the mould if the next welding is done within 15 minutes as it conserves the previously generated heat.

STEP - 7: 
Place the conductors in the mould and close the handle clamps to avoid material leakages during the reaction.

Please Note – If there is even a minor gap between the two Conductors, apply Sealing Compound at the places where the conductors is passing out else at the time of Welding, the Powder will spread out as a flame resulting in improper joint
 

STEP - 8:
Obstruct the tap hole with the metallic disk.
 

STEP - 9:
Empty the contents of the welding mixture package.
  

STEP - 10: 

Empty 50% of the starting powder above Exothermic Weld Powder (Don’t Mix, just scatter) and than Close the Mould Mouth and than the rest 50% Starting Powder, Sprinkle it on the Mould Mouth nearby the small hole given on the top of the Mould.
  

STEP - 11: 
Ignite the starting powder extended on the top/side of the mould using the flint igniters.
 

STEP - 12:  
Once started, the reaction will take 3-4 seconds during which it is recommended to stand clear of the mould. 

  
STEP - 13:   
After at least 2 minutes of the bonding, open the mould by undoing the handle grip. Remove the mould from the joint and clean the joint for any slag. Once open, clean the slag sticking to the mould with the relevant tool and clean the cavities. The mould will be ready now to use again without having to reheat it as it is already warm.

 

 

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. 

MAINTENANCE & STORAGE INSTRUCTIONS:

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.

 

WARNING :

1.  Products shall be installed and used only as indicated in product instruction sheets.

2.  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.

3.  All instructions must be completely followed to ensure proper and safe installation and performance. 

4.  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.