Structural Flakeboards and Composites 3049 



Table 24-31 . — Modulus of elasticity (measured by two methods) and tensile strength of 

 1 .5 -inch-wide, defect-free strips of 0.160-inch veneer rotary -peeled from hardwood trees 

 12 to 20 inches in diameter of four species cut at three locations in the Southeast (Data 



from McAlister')^ 



Region Modulus of elasticity Ultimate 



and species Dynamic Static tension tensile strength 



Million psi Psi 



Georgia Piedmont 



Sweetgum 1 .75 1 .37 6,032 



White oak 2.20 1.67 6,511 



Yellow-poplar 2.02 1.74 7,087 



North Carolina Mountains 



White oak 2.00 1.51 3,181 



Yellow-poplar 2.12 1.73 4,565 



South Carolina Coastal Plains 



Black tupelo 1 .85 1 .48 2,989 



Sweetgum 1.91 1.54 2,913 



Yellow-poplar 1.88 1.47 3,118 



'McAlister, R. H. Manuscript in preparation. Modulus of elasticity and tensile strength distribu- 

 tion of veneer of four commercially important southeastern hardwoods. Southeast. For. Exp. Stn., 

 U.S. Dep. Agric, For. Serv., Asheville, N.C. 



^Each value is an average based on a total of 30 specimens sampled from each of 137 to 277 trees 

 per species. Eight-foot peeler logs from these trees were cut to a minimum top diameter of 8 inches 

 inside bark. Moisture content at test was about 10 percent of ovendry weight. 



A similar analysis of composite joists (fig. 24-58 bottom) using oak, yellow- 

 poplar, and sweetgum veneers is available. '"^ 



Koenigshofs (1981) study of economic feasibility of manufacturing COM- 

 PLY studs and joists from southern hardwoods is summarized in section 28-28. 



24-23 MOLDED FLAKEBOARD 



The molding of flakes is a technology somewhat distinct from that of molding 

 fibres or small cubical particles. Pages 1207 and 1208 of Agriculture Handbook 

 420 (Koch 1972) describe some parameters affecting molding of fine particles. 

 Section 22-10 of this text describes under paragraph heading Recycled cross ties, 

 a crosstie molded from particles derived from old crossties. Additional refer- 

 ences related to molding particles are Molsemi (1974a), Prusakov et al. (1975), 

 Bazhenov and Samkharadze (1977), Maloney (1977), and Ward (1978). Ruppin 

 (1979) discusses the manufacture of molded articles from waste paper, and 

 Oroszlan (1978) describes a Czechoslovakian three-stage process to mold fiber- 

 board automobile parts. 



'"^Koenigshof, G. A. Strength and stiffness of COM-PLY joist. Southeast. For. Exp. Stn., U.S. 

 Dep. Agric, For. Serv., Fin. Rep. FS-SE-3501-26(1), in preparation 1982. 



