Steaming Under Restraint to Remove Warp in Dried Softwood Studs

Kiln-dried ponderosa pine and white fir studs previously rejected for excessive warp were conditioned to a moisture content of 18 percent. They were then clamped and held in a straightened position. The clamped studs were placed in a cabinet and low pressure steam injected. Four different combinations of steaming and drying schedules were used. Measurements of crook, bow and twist were made both before and after treatment. All material was at an MC of 12 percent at the time these warp measurements were made. None of the methods were effective in upgrading the defective material. Twist was the worst and the most prevalent defect both before and after steaming.

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