Graphite absorbs moisture from weather. So there is a need for propane torch to dry out the inside of the mould thoroughly on both sides, therefore heating the mold to approximately 250 degrees Fahrenheit We recommend using one Flame torch for Every 200 Joint and than use the refiling Product Features For Exothermic Welding: Safe operation, without professional technology knowledge or any other special protection, easy to learn. Without external energy, very simple tools and equipment, execution of high efficiency. Connector in copper of high purity, strong corrosion resistance. The connector to be formed in metal bonds, not loose. Current carrying capacity of the connector is greater than that of wire connector. Widely applied , can be used for copper to copper, copper to steel, welding between copper and galvanized steel and other metal materials. Connectors can withstand multiple large inrush current impact without degradation.