Abstract: Improved apparatus for weld bonding together a pair of conductors separated by a layer of thermo-plastic insulation material. The apparatus comprises a pair of welding electrodes for urging the pair of conductors together at a first level of electrode squeeze pressure while a first low level of current flows through the electrodes and conductors until the thermo-insulation material between the conductors beneath the electrodes is penetrated, electronic circuits for sensing this insulation penetration and initiating after a pre-selected time delay, a second higher level of welding current and electronic controls for increasing the electrode squeeze pressure from the first level to a second higher or forging level for at least a portion of the flow of the second higher welding level of current. A method for forming the weld bond is included.