Abstract: A method of making metal castings is disclosed, and particularly a method for making ferrous castings employing multiple component sand core assemblies. The core assembly is devised to receive a disintegratable strap about one annular outer surface path of the assembly. The strap is drawn tight about the assembly by an automated strapping machine and fused to provide a positive mechanical securement. The strap is preferably arranged coplanar with the outer surface of core prints when used in the assembly. The strapped assembly is placed in any desired orientation within a bonded sand mold and molten metal introduced therein. The molten metal heats the mold and core surfaces and surrounding sand body to such an extent that the strap is volatilized immediately after the introduction of the molten metal.