Gypsum boards are bent to curved shape by placing a water dampened flat rectangular gypsum board upon a resiliently bendable panel positioned below a bender shell having a wall of arcuate cylindric contour which grips a margin of the gypsum board, and rolling the bender shell upon the gripped board to...http://www.google.com.au/patents/US7670129?utm_source=gb-gplus-sharePatent US7670129 - Process and apparatus for bending gypsum board
