Abstract: Apparatus and methods convert a MIG welder into an effective cutting machine. A plug adaptor is installed into the existing MIG welder gun cup nozzle, which has an inside diameter and a length. A contact tip within the cup has an outside diameter, and shielding gas ports in the cup typically surround the contact tip. The plug adaptor comprises a body having a width dimension corresponding to the inside diameter of the cup, a length corresponding to the length of the cup, and a central bore corresponding to the outer diameter of the contact tip. A channel is established between the width dimension of the body and the inside diameter of the cup enabling air to flow from the shielding gas ports to a workpiece for slag removal produced during the cutting operation. The MIG gun is not modified in any way except for the addition of the removable adaptor.