Abstract: An internal pipe clamp is provided by the present invention. The clamp is designed to clamp two joints of pipe into position for a circumferential weld. The clamp includes mechanism for spacing the two joints apart a very short distance to facilitate welding. A backup member is provided which is movable from a retracted position. The backup member comprises two backup portions each of which comprises two pivotally coupled backup segments. Each segment extends through an arc of approximately 90.degree. and terminates in a wedge shaped end that is complemental to the wedge shaped end of an adjacent segment. Power cylinders move each segment from a retracted to an extended position. Power cylinders are also coupled in opposed relationship with each adjacent pair of wedge shaped ends to force same into tight contiguous relationship when the segments are extended.