A novel welding and annealing method for the convenient production of thin film specimens containing different types of controlled grain boundary structures has been developed. Bicrystals containing controlled grain boundaries in their midplane were produced by welding single-crystal thin films together face-to-face. Polycrystals containing columnar grains of only two crystal orientations were produced by annealing the previous bicrystals. Polycrystals with columnar grains of only three orientations were produced by extensions of the method in which films of three orientations were welded together and annealed. The types of grain structures which can be obtained by these techniques are described, and the potential uses of such specimens are discussed. © 1976.