Exothermic Welding
A chemical reaction welding process where melting heat is generated by the exothermic reduction of metal oxides with aluminum powder. It is predominantly used for electrical grounding connections.
Exothermic welding is basically a little aluminum theater: you mix aluminum powder with metal oxide, ignite it, and get a hot melt that cleanly joins the parts. It runs without an external power source and is ideal for grounding connections because the melt really flows well into the contact surfaces. Make sure the mold is dry and clean, otherwise the stuff will bubble up in your face. If the powder mix is wrong or you use too little, the melt will be cold and the joint won't hold. And you don't want to inhale the fumes that come off, so ensure good ventilation or do it outside. After igniting, wait briefly for the reaction to finish, then remove the mold and let the part cool down in peace. When you remove the slag, you'll see if the melt ran through cleanly. If not, redo it, but grind the surfaces shiny beforehand.