The Automated Bond Evaluation System (ABES) is an invaluable tool in evaluating the bonding characteristics of adhesives. The system uses minimal amounts of adhesive and wood while avoiding the difficulties associated with density variations in OSB panels manufactured in the laboratory. Since the quality and uniformity of the wood substrate can be controlled by careful selection the key factor in comparing adhesive performance is the moisture content of the wood strands used in the test. This study examines the uniformity of moisture content of strands exposed to selected conditions in environmental chambers.
Aspen strands of 0.69 mm (27 thousandths of an inch) absorb or give off moisture fairly readily and equilibrium conditions are generally established in 4 hours or less. The equilibrium moisture content of aspen strands approximates that of solid wood but is not identical to that predicted by the Wood Handbook tables. Aspen strands are more susceptible to moisture content fluctuations than solid wood and strand moisture content should be confirmed prior to use in the ABES equipment.