Patent ID: 8123991

Claim:
A method of making wallboard comprising, in sequence: a) forming a continuous length of wallboard having first and second surfaces, longitudinal edges running the length of the continuous length of wallboard, and a recess in the first surface along each longitudinal edge; b) cutting an unfinished length of partially cured wallboard from the continuous length of wallboard; c) forming a plurality of lateral recesses in the first surface of the wallboard, one lateral recess at each lateral edge of the unfinished length and at least one lateral recess parallel to and offset from the lateral edges; and d) cutting the unfinished length of wallboard at the at least one offset lateral recess to form a plurality of finished lengths of wallboard such that each finished length of wallboard has recessed edges along all four edges of the first surface; wherein said process further comprises the step of selecting presses for forming the lateral recesses i) from a plurality of prepositioned presses on a recess forming apparatus, the selected presses corresponding to the position of the lateral edges and the desired location of the at least one offset lateral recess or ii) from a plurality of presses on a recess forming apparatus, at least one of said presses being movable from one position to another on the recess forming apparatus, wherein the presses are positioned at points corresponding to the lateral edges of the wallboard to be acted upon as well as at the location of the offset lateral recess(es), prior to forming the plurality of lateral recesses in step (c).