Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. In one embodiment, the outer cover layer is formed from a composition comprising a thermoplastic polyurethane and epoxy compound. Mixtures of multi-functional amines and imines, and multi-functional isocyanates, and epoxy curing agents; and solvent, can be applied to the outer cover. The resulting coating may contain polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. The coating methods have many benefits and the finished balls have good physical properties.