several approaches are listed below that make possible the fabrication of hollow enclosed structures and thus the elimination of problems associated with mechanical attachment welding brazing and lower strength materials the common concept for each method listed below is the use of a solid state joining process that produces a higher quality joint without strength reductions or material selection limitations there are many enclosed hollow structures that could be discussed in this invention to illustrate the concepts of the embodiments of the invention listed below these structures could be large or small symmetric or asymmetric the same material or dissimilar materials and many other possible configurations or combinations without departing from the spirit of this invention and the many applications of a hollow structure geometry the fabrication of a sphere is used herein to clearly illustrate the invention friction stir welding the concept of friction stir welding fsw has been well documented over the past several years however a novel approach using fsw to create a hollow sphere is described herein base materials such as steel aluminum nickel copper or any material could be used in this concept to create a hollow metal sphere in this example a hollow sphere is made using aa 7075 an aluminum alloy that is considered unweldable it is important to note that aa 7075 is used in the aircraft industry in sheets which are riveted.