When parts are joined using friction stir welding, intersecting welds may often be performed.  For each weld, an opening is formed at the location where the welding tool exits the parent material.  Weld-exit openings are generally not desirable, particularly when a subsequent weld traverses the opening.  Specifically, welding over an opening may cause voids in the weld nugget, thereby reducing the joint strength and creating surface imperfections due to the volumetric material deficiency in the weld.  Various approaches for filling weld-exit openings have been proposed.  For example, wedges having polygonal cross-sections may be staked into the openings using punches and hammers.  However, this process is time consuming and only marginally effective since the polygonal cross-sectional shape of the wedges produces voids upon installation of the wedges into the parent material.  Furthermore, the staked wedges may be ejected from the openings during the subsequent weld.  Alternatively, reaming out the openings and press-fitting cylindrical members therein unfavorably increases the manufacturing cycle time.