The present invention is a method for manufacturing inflatable articles, or bladders for inflatable articles, that is time-efficient, simple, inexpensive and permits the uninterrupted manufacture of numerous and even customized article or bladder configurations and sizes, without expensive configuration-specific, metal tooling. The present invention provides a golf ball of the present invention has a core and a cover, wherein the cover is formed from a cover composition that contains, as a resin component, a thermoplastic polyurethane and a urethane prepolymer having two or more isocyanate groups. The metal foam core is provided in a special manner with a partial core which is supported on a top core of a casting die tool so as to provide positioned bearing in the casting die tool. If disengaged, the safety fastener is easily restored to operational use.