Abstract: An improved back-up tape for use in fusion welding metal sheets and structures is disclosed. The tape comprises a rolled refractory fiber fabric partially flattened against an adhesive coated surface of a wider, heat resistant, strip. In use, the tape is pressed against the back side of a joint or other weld line to be welded with the adhesive bonding the tape along strips parallel to but slightly spaced from the weld line and the roll pressed against the joint. Fusion welding is conducted without the addition of any filler wire. A flat weld underbead, with no molten metal drop-through is produced, with no melting or other significant change in the tape. The tape is then stripped off and the welded structure is ready for use.

Abstract: An improved back-up tape for use in fusion welding aluminum sheets and structures is disclosed. The tape comprises a small diameter, heavy wall, flexible woven refractory fiber tube within a slightly larger diameter similar tube, both partially flattened against an adhesive coated surface of a wider, heat resistant, strip. In use, the tape is pressed against the back side of a joint to be welded with the adhesive bonding the tape along strips parallel to but slightly spaced from the joint. The joint is fusion welded without the addition of any filler wire. A flat weld underbead, with no molten metal drop-through is produced, with no melting or other significant change in the tape. The tape is then stripped off and the welded structure is ready for use.