Face check development in veneered furniture panels

This project studied check develop in 1-foot square veneered furniture panels. Wood species used were flat-sliced red oak and hard maple cut on a half-round machine. The veneer flitches were clipped to 6-inch widths with the cathedral centered, book matched, and spliced. The resulting faces were 12 inches by the length of the veneer flitch. One set of veneer faces was conditioned at 35 percent relative humidity (RH) and 72°F. The second set of veneer faces was conditioned at 65 percent RH and 72°F. The panel core used was 11/16-inch southern pine particleboard. The particleboard core stock was all taken from the same bundle. The particleboard core was conditioned at 35 percent RH and 72°F. The adhesives used were urea-formaldehyde (UF) and precatalyzed cross-linked PVA. The assembly times were 1 minute and 10 minutes. The panels were first exposed for 3 weeks at 75 to 80 percent RH and then 3 additional weeks at 20 to 25 percent RH. This cycle was repeated three times. After every 3-week exposure, the panels were examined for the number of veneer checks. The panels were also evaluated for veneer checking as they were removed from the hot-press. Thus, the panels were evaluated seven times. The Student-Newman-Keuls test was used to evaluate the presence of face checks. The combination of factors resulting in the fewest face checks for red oak veneered panels was UF adhesive, loose side out, faces conditioned at 35 percent RH, and 1-minute assembly time. Six of the panels in this test were check free and two panels developed just one check each. For hard maple veneered panels, the combination of UF adhesive, tight side out, faces conditioned at 35 percent RH, and 1-minute assembly time resulted in no face check development.