The butt fusion technique does not require additional couplers. The two pipes to be joined together are cut to length before the welding and clamped in the basic machine without stress or misalignment. The pipe faces are then planed parallel to each other. Then both pipe ends are simultaneously brought into contact with a heating element which transfers heat energy to the pipe faces.
After an adaptation time, the almost pressureless heating time follows. Once both pipe faces are in a thermoplastic state, the heating element is removed and the pipe ends are brought together quickly but carefully. The joint remains under pressure until the temperature in the welding zone has fallen below the melting point of the plastic. The result is a pressure-resistant and gas-tight joint.