Welding apparatus and methods for welding

An apparatus for use in welding a first pipe free end to a second pipe free end, said first and second pipe free ends each having a diameter of less than about 12 inches, said apparatus comprising:

• a) a guide rail;
• b) a first clamp mounted to the guide rail, the first clamp comprising
• a first horizontally extending trough defining a concave recess opening vertically configured to receive and support against gravity the first free end, and
• at least a first pair of opposed pivoting jaws, each of the opposed jaws of the first clamp pivotable about a different axle and actuable relative to the first trough between an open position and a closed position such that the first clamp defines a first pipe receiving channel portion configured to grip an outer surface of the first free end and compressively reconform an open cross-section of said first free end;
• and
• c) a second clamp mounted to the guide rail in axial alignment with the first clamp, the second clamp comprising
• a second horizontally extending trough defining a concave recess opening vertically configured to receive and support against gravity the second free end, and
• at least a second pair of opposed pivoting jaws, each of the opposed jaws of the second clamp pivotable about a different axle and actuable relative to the second trough between an open position and a closed position such that the second clamp defines a second pipe receiving channel portion configured to grip an outer surface of the second free end and compressively reconform an open cross-section of said second free end and cooperating with the first pipe receiving channel portion such as to form a channel, an open cross-section of said second free end,
• wherein at least one of said first and second clamps being actuable to move along the guide rail to hold said first pipe free end or said second pipe free end in close coaxial opposition with the other of said first pipe free end or said second pipe free end wherein the apparatus further comprises a movable frame configured to support the guide rail, and a roller assembly movably mounted to the movable frame and configured to support the first pipe or the second pipe, the roller assembly being configured for movement relative to the frame between a first position where the first free end or the second free end is disposed in the first trough or the second trough, and a second position vertically spaced from the first position such that said first pipe free end or second pipe free end is suspended above the first trough or the second trough, respectively, and wherein the frame or the pipe is configured such that said frame or pipe can be advanced in an axial direction when the roller assembly is in the second position.