Patent ID: 8066174

Claim:
A friction stir welding method comprising: rotating a tip of a friction stir weld tool while moving the tip of the friction stir weld tool orthogonal to a friction stir weld tool longitudinal axis, wherein a friction surface on the tip is configured to a create the friction stir weld by penetrating the substrate to a bottom of a friction stir weld; feeding a filler material through a first passage in the friction stir weld tool and into the substrate wherein the filler material emerges from the tip at the bottom of the friction stir weld; and rotating the filler material as the filler material enters the first passage, wherein the rotation of the filler material is about a longitudinal axis of the first passage, is independent of the rotation of the friction stir weld tool, and is effective to create relative circumferential movement between the filler material within the first passage and a surface of the first passage.