US Patent 11771966 Golf club head comprising microscopic bubble material

A golf club head with a face component having a variable thickness and a coating on a rear surface of the face component that provides a flat surface to which a medallion can be affixed, and methods of manufacturing such golf club heads, are disclosed herein. The coating is made from a fill material comprising a polymer and a plurality of microscopic bubbles, which preferably constitute 5-70% of the volume of the fill material. The polymer material preferably is a polyurethane having a Poisson's ratio of 0.40-0.50.