Home Products Alloys TIG Rod WeldPak XL WELDPAK®XL WeldPak XL is a heat-treatable copper nickel tin metal engineered specifically for TIG (GTAW) weld repair of ToughMet and MoldMAX XL. ADVANTAGES AND BENEFITS WeldPak XL is a non-beryllium containing alloy that is heat treatable to match the hardness of the base metal. Unlike copper beryllium, this filler metal has a tendency to form porosity, so it is important to use a small bead and to work the repair slowly. USES AND APPLICATIONS WeldPak XL is used as filler metal for TIG (GTAW) weld repair of MoldMAX XL and ToughMet alloys. It is commonly used for repairing cracks or building up worn surfaces. AVAILABLE SPECIFICATIONS AND STANDARDS Meets UNS C72900. CHEMICAL COMPOSITION Nickel - 14.5-15.5% Tin – 7.5-8.5% Copper - balance PHYSICAL PROPERTIES Melting Range – 1740-2040° F (950 - 1115°C) Thermal Conductivity – 22 BTU/ft-hr-°F (38 W/m-°C) after heat treating MECHANICAL PROPERTIES As deposited, the weld bead will have the strength and hardness of annealed copper nickel tin (HRB 55-80). By heat treating the part for 3 hours at 700°F (370°C), the weld bead can be hardened to HRC 30. However, the TS tempers of ToughMet should not be heat treated after welding, as this would destroy the properties of the base metal. FORMS, SIZES AND TOLERANCES WeldPak XL filler rod is available in short lengths in diameters of 1/16” (1.59 mm).