Internal steam pressure produced during the hot-pressing cycle in particleboard production is critical to the newly developed bond strength that will determine the overall performance of particleboard. The difference between the accumulation of internal steam pressure for small panels made in the laboratory and that of large commercial-sized panels makes it difficult to transfer knowledge gained from the laboratory to the commercial plant. The objective of this research project is two-fold: to investigate the effect of panel size on the initial development and subsequent dissipation of internal steam pressure during the hot pressing cycle; and to develop improvements on small laboratory presses to better mimic conditions experienced in the large press used in the manufacturing plant. In this study, changes in the panel size from 56 by 56 cm to 86 by 86 cm resulted in changes in the maximum steam pressure of up to 3.5-fold. A collar made from a steel rod was used, which prevented steam from escaping and helped to build higher internal steam pressure in smaller panels. Finally, the effects of a ��burp'' (briefly opening the press during the press cycle) or use of a forming screen were also studied in relation to internal steam pressure. This research was conducted as collaboration between scientists at FPL in the Engineered Composites Science research work unit and Heartland Research Technology Inc.