SPC22131 Solder Wire, 63/37, 0.64mm Diameter, 183°C, 454g. The SPC22131 is a high activity core flux Solder Wire designed for excellent instant wetting action, even on nickel surfaces. Although it is a RA-based material, the residues are non-corrosive if not cleaned. It accepts 22AWG standard wire gauge and 63/37 alloy content tin/lead. It is a high-activity water-soluble core flux for soldering difficult metals. It is designed for optimal cleanability, along with minimal smoke and odor.