Postalloy 53 Insulated Tool Kit Smart Magnet Technology To Ensure SPF50 UVA UVB advanced Smart Magnet Technology To Ensure Sufficient Magnetic Adhesion Boot Tread POSTALLOY 53SPL is a solid gasshielded welding wire isdesigned for joining and buildup on various types of cast ironsuch as ductile nodular gray and Niresist Also for weldingcast iron and cast iron to steel or stainless steelThe unique chemistry of POSTALLOY 53SPL providesweld deposits that are fully machinable Under normalcircumstances if dilution is kept to a minimum there is noundercutting and weld deposits can be machined through thefusion zone even with high speed steel tooling