Under GMA surfacing, the minimization of the base metal in the deposited metal and its shaping is highly determined by the polarity of the welding arc. The article covers the research on the influence of arc polarity on the formation of a weld pool. It has been determined that with a direct polarity of the arc and a given amount of deposited alloy, the required arc current is greatly reduced, and the penetration of the base metal is reduced. However, at the same time, the contact angle between the surface of a weld bead and the base metal decreases to values less than 90 degrees, wherein the probability of lack of penetration in the overlap of the beads increases. Therefore, surfacing with a reversed-polarity current, given the fact, that welding modes are rationally chosen, is preferable.