Titanium investment castings provide a major cost savings in comparison to machined parts and built-up structure. Welding titanium castings provide large structural monoliths that further improve cost savings by eliminating fasteners and reducing assembly time. Welding also compensates for casting size limitations imposed by mold size, ladle pour weight and HIP chamber size. They bring designs to take advantage of the casting process and welding process is a major contributor to having a producible design, lowering the cost of the castings. This paper presents the results of a program initiated to determine the effects of welding on the mechanical properties of cast titanium alloys (6Al-4V) using three different welding processes (LBW, PAW, EBW): four different material thickness' (3mm, 5mm, 10mm, and 19mm) and two different heat treatments. Data produced during the course of this investigation will demonstrate the usability of welded cast titanium for primary airframe structure.