Water Soluble Paper and Tape, 2 in W x 300 ft L, Tape, White ORS NASCO Designed for welding gray iron Designed for welding gray iron castings to themselves as well as joining them to mild steel Can also be used to repair castings A preheat and interpass temperature on at least 350°F is required during welding Thicker mil thickness with heavy embossing 10° F temperature resistance Non flammable leaving no residue in pipeline Provides a convenient and cost effective method for creating purge chambers for pipe welding Low air permeable purge gas barrier for TIG welding Excellent barrier for retaining noble gas (argon and argon helium mix) Simple and fast construction Dissolves effortlessly and rapidly during water or steam hydro test