| Summary: | A new version of a weathering device (Accelerated Check Tester, ACT) was built, and weathering cycles for accelerating the surface checking of decking board samples exposed in the device were developed. The device permits the testing of realistic-sized decking board samples that are oriented horizontally and restrained in the device by screws. Two experiments were carried out to validate the device and associated test cycles. In the first experiment, southern pine (Pinus sp.) and western red cedar (Thuja plicata) samples were exposed to 6 different cycles in the ACT to determine which elements of weathering cycles (moisture, heat, freezing and UV radiation) were critical to the ACT’s function of accelerating checking. Large number of checks developed on the surface of samples subjected to wetting and drying cycles. Samples subjected to a cycle that also involved UV exposure developed significantly more and larger checks than samples subjected to any of the others cycles. Checking was much more pronounced in southern pine than in western red cedar samples. The second experiment examined the checking and distortion that developed in artificially weathered boards compared to those that developed in naturally weathered boards. Matched pairs of kerfed and unkerfed southern pine boards were subjected to accelerated weathering in the ACT or natural weathering. The number and length of checks that developed in boards exposed in the ACT were similar but not identical to those in boards subjected to natural weathering. The width of checks was greater in boards subjected to accelerated weathering. Kerfing had no significant effect on checking or distortion of boards. Exposure of boards in the ACT accelerates checking approximately 16 times compared to natural weathering. The Accelerated Check Tester should be a very useful tool for obtaining information on factors that affect the checking of wood.
|
|---|
