What is Back Gouging Aluminum miller blades are mainly seen in the marine industry. They are used for what is called back gouging on aluminum when welding. The miller blade can be used for milling, cleaning up and grooving, and cutting out welding tacks. These blades are made to industry standards and can be sharpened many times. Back gouging is the removal of weld and base metal by arc gouging or grinding from the other side of a partially welded joint to assure complete fusion and penetration upon subsequent welding from that side. Welding aluminum without making a back gouge before we..