In accordance with one embodiment of the present application, provided is a welding support structure arrangement to support an elongated assembled weldment preparatory to positional welding. The arrangement includes at least one support structure having a support base and a movable platform connected to the support base by spaced-apart 2-bar linkages with center pintels and a series of length adjusting members between the pintels and the support base. A length adjusting member is located between the movable platform and the support base, wherein the lengths of the length adjusting members set the orientation of the movable platform.