A welding apparatus for welding a work-piece includes an energy source configured to generate a weld in a zone of the work-piece, with the work-piece characterized by a layer. The apparatus also includes a first wheel characterized by a first circumference and a first set of protrusions disposed on the first circumference, and a second wheel characterized by a second circumference and a second set of protrusions disposed on the second circumference. Each of the first and second wheels is configured to rotate relative to the work-piece, and the first and second sets of protrusions are configured to disrupt the layer as the work-piece is traversed between the first and second wheels. The energy source generates the weld in the zone of the work-piece following the disruption of the layer. A method employing the disclosed welding apparatus is also provided.