How to do Exothermic Welding

How to do Exothermic Welding / Process for Exothermic Welding

The Exothermic Weldings process 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, conductors are prepared, placed in a purpose designed graphite mould, and exothermically welded to produce a permanent molecularly bonded electrical connection. The steps outlined below are a general demonstration of a typical welded connection. These basic steps are used for all electrical connections. Be sure to read and follow the instructions included with every Mould before making a connection.

 Exothermic Weldings Accesories

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 all the Accessories as listed on Exothermic Weld Accessories page. Check to ensure the graphite Mould 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 Mould. Make adjustments to tighten/loosen the handle clamp.

STEP – 6:
The material to be welded (cable, rod, tape etc.) must be clean using the wire Brush and dry using the Flame Torch 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 again to avoid a porous welding.
P.N – 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.

Exothermic Weldings Process

STEP – 7:
Place the conductors in the mould and close the handle clamps to avoid material leakages during the reaction.
Please Note – Always apply Sealing Compound at the places where the conductors is passing from the mould else at the time of Welding, the Exothermic Liquid will spread out as a flame resulting in improper joint

STEP – 8:
Place the metallic disk inside the mould and ensure that Powder should not enter into Weld Cavity.

STEP – 9:
Pour Exothermic Weld Powder into Graphite Mould. (Pour the Powder recommended and supplied by us)

STEP – 10: 
Empty 50% of the starting powder above Exothermic Weld Powder (Don’t Mix, just scatter) and then Close the Mould Mouth and then the rest 50% Starting Powder, sprinkle it on the Mould Mouth nearby the small hole given on the top of the Mould Mouth.

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 8-20 seconds during which it is recommended to stand clear of the mould.

 STEP – 13:  
After at least 3 minutes of the Mould cooling down, open the mold by undoing the handle grip. Remove the mould from the joint and clean the joint by removing slag with help of Slag Removal Tool and hard brush. Then clean the weld cavity with soft brush gently. The mould will be ready now to use again without having to reheat it as it is already warm.

Exothermic Weldings - Copper to Copper - T Joint

In Normal case minimum two mold should be used on site to keep the process continue while one mold is cooled and cleaned after firing, the other should be used. The task should be undertaken very peacefully and one should not hurry.