An apparatus and method for reducing the amount of wallboard wasted during the manufacturing process is disclosed. Wallboard sections that contain a cover paper splice, which sections must go to waste, are reduced in size during the manufacturing process. This is accomplished by determining the optimum location for a cover paper splice to be made and making the splice at or near this location, such that a rotary knife can readily isolate the splice onto a section of wallboard having a reduce length. This function is accomplished using any suitable computer equipment capable of monitoring desired manufacturing conditions and using this data to calculate the optimum location for a splice.