A system is for bonding a cover sheet to a core to form or repair a dual wall structure. The system includes a cover sheet probe and an inner pedestal probe. A three dimensional contoured tip of the cover sheet probe abuts against a three dimensional contoured outer surface of the cover sheet opposite a pedestal of the core. The pedestal abuts the inner surface of the cover sheet. The inner pedestal probe may be coupled to the core to create a conductive electrical path from the cover sheet probe through at least part of the structure. A flow of electric power is controlled and supplied to the cover sheet probe to heat a junction between the area of the cover sheet abutting the pedestal and the pedestal. A heated area is created in the junction and fixedly couples the coversheet and the pedestal.