Abstract: A base metal having at least one curved major surface is placed on a hard plate in such a way that the curved surface is in opposed relationship with the hard plate, and a cladding metal sheet is placed in opposed and spaced-apart relationship with the upper flat major surface of the base metal. The cladding metal sheet is firmly bonded to the base metal by explosive welding, and the curved surface of the cladding metal bonded becomes substantially in conformity with the curved surface of the base metal prior to the explosive welding. A clad metal sheet with a higher degree of dimensional accuracy may be provided and the bond is very strong and highly reliable. With copper base metal and composite cladding metal sheets each prepared by butt-welding foreign metal sheets which may be different in thickness, a mold for continuous casting may be produced which may substantially eliminate casting defects.