Fluid tooling for use in an inductive welding system for creating a fusion bond along a bond line between two thermoplastic parts includes an elongated vessel made of fluid impervious flexible material and having an elongated axis and an open end at each axial end of the vessel, closed and sealed by end closures. A coil is received in the vessel for generating an alternating magnetic field transverse to the longitudinal axis. A linear guide in the vessel extends axially for substantially the full length of the vessel and guides the coil for movement axially through the vessel. Power leads are connected to the coil and extend through a pass-through in one end closure to connect the coil to a source of high frequency electrical power of about 35 KHz to energize the coil to produce an alternating magnetic field. A pair of magnets guided along opposite sides of the vessel and magnetically coupled to a ferromagnetic mass connected to the coil move the coil axially along the vessel over the bond line at a controlled speed. A backup structure exerts a downward force along the top of the vessel, pressurizing fluid sealed in the vessel and distributing pressure uniformly over the top surface of the top part to press the top part against the bottom part and facilitate fusion bonding of the thermoplastic in the faying surfaces of the interface.