Abstract: A method and apparatus for solid phase welding of pipes. A first internal clamping mechanism is employed substantially immediately adjacent the end of each pipe to urge each end into circumferential accuracy. A second internal or external clamping mechanism is employed in axial spaced relation to the first mechanism and which bears upon a greater surface of the pipe than the first mechanism, and is utilized to urge the two pipe ends together so that in combination with the application of heat, a pressure weld, joining the pipe ends, is effected.