Abstract: A welding tool is disclosed comprising a working electrode and a ground electrode. A tool body comprises means for holding the electrodes in a contiguous, spaced-apart, side-by-side relationship. The electrodes are movable along parallel axes to and away from the tool body. A first compression spring biases the working electrode away from the tool body, and a second compression spring biases the ground electrode away from the tool body. The electrodes comprise stops by which the electrodes are positioned at a predetermined distance from the tool body against the bias of the compression springs. A switch responsive to movement of the working electrode, on movement from said predetermined distance toward the tool body, closes an electrical circuit to supply power to the electrodes. The welding tool comprises means by which the electrodes can be applied to a common side of the workpieces being welded, or to opposite aligned sides of the workpieces being welded.