Process for straightening and drying southern pine 2 by 4's in 24 hours

Abstract

In 21 hours under mechanical restraint and in a kiln providing a cross-circulation velocity of 1,000 f.p.m. at dry-and wet-bulb temperatures of 240 and 160^oF., followed by 3 hours at 195 and 185^oF., southern pine 2 by 4 studs cut from steamed veneer cores or small logs were dried to 9-percent moisture content (Standard deviation was 3 percent). Compared to studs dried at temperatures not in excess of 180^oF., the high-temperature studs were substantially straighter (crook, bow, and twist averaged 0.12, 0.21, and 0.09 inch), of higher grade (91 percent in SPIB grades 1, 2, and Stud), and not significantly weaker. Neither schedule caused casehardening. The high-temperature schedule took less than one-fourth the time and about one-half the total energy required by the low-temperature schedule. when lumber dried on both schedules was exposed to extremely humid or dry atmospheres, warp in the steam-straightened 2 by 4's remained less than that measured on conventionally dried studs.

Citation

Koch, Peter. 1971. Process for straightening and drying southern pine 2 by 4''s in 24 hours. Forest Products Journal, Vol. 21(5): 17-24