Practical drying techniques for yellow-poplar S-D-R flitches

The S-D-R (Saw-Dry-Rip) process is a proven method of reducing warp in manufacturing hardwood studs. It has been assumed that its success is partially due to the stress relaxation caused by high-temperature drying. Implementation of this S-D-R process in the Appalachian region has been limited as few mills in this area have this drying capability. The purpose of this study was to investigate the effectiveness of high-temperature and steaming treatments before solar and air drying S-D-R flitches on reducing warp and to determine the cost of application of successful methods. An initial study was conducted to establish the duration of treatment required to relieve growth stresses in short S-D-R flitches. Steaming for 15 hours resulted in a substantial decrease of average stress. Steaming times of 15 and 20 hours and high-temperature durations of 7 and 15 hours were chosen for treating green S-D-R flitches. S-D-R flitches were divided among the four treatments and a control group. One third of the flitches from each group were subsequently dried in a solar kiln; the rest were air dried. All flitches were then ripped into 2 x 4's and bow, crook, and twist was measured for each stud. A comparison by the percentage of studs rejected from No. 2 dimension because of warp showed no significant difference between any treatments (including the control) or between drying methods. Comparisons based on actual amount of warp found small differences between drying methods and between treatments, depending on the type of warp considered.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Forest Products

Department dc:contributor.department

Forest Products

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1982

Author dc:creator

• Weik, Bruce R.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/82881

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/82881