Abstract: A portable seam welder comprising a pair of arms pivoted to one another about a pivot axis and a spindle assembly mounted on each arm. Each spindle assembly includes a shaft rotatably mounted about an axis extending generally parallel to the pivot axis and perpendicular to the longitudinal axis of the arm. A welding wheel is mounted on each shaft. At least one of the wheels is driven to rotate it. Handles are mounted on one of the arms for manipulating the welder, and an actuator means extending between the arms for pivoting the arms relative to one another for moving said wheels toward and away from one another.