A capability for welding in-space as a method of making permanent joints for vehicles and structures assembled on-orbit is under development. This project is part of an in-space assembly and construction program to develop the requirements and technology needed to build elements in space. This paper describes an approach to the welding of tubular truss strut joints for a range of diameters. The conceptual design of a mechanism to position the strut in the truss and weld it in place is also outlined. Considerations for the use of welding as a tool for in-space construction are discussed.