3028 Chapter 24 



24-19 COMPOSITE PANELS WITH VENEER FACES 

 OVER FLAKE CORES 



Alignment of face fibers, particles, flakes, or strands can enhance important 

 properties of wood-based panels. Use of veneer as face layers provides a conve- 

 nient way of obtaining near-perfect fiber alignment. 



During the mid-1950's Elmendorf Research, Inc. developed a product, Nu- 

 Ply, which had thin hardwood veneers on a particleboard or fiber core. It was 

 made with green hardwood veneers which were dried, bonded to the core, and 

 the core consolidated, in one hot pressing. The Nu-Ply Corp. in Bimidji, Minn., 

 resulted from this development; applicable patents have since expired." 



Potlatch Corporation began research in 1968 on oriented strand board and 

 oriented strand cores for composite softwood panels, and in the fall of 1971 first 

 produced veneer-over-flake-core panels in their pilot plant. Their commercial 

 plant in Lewiston, Idaho, started manufacturing softwood composite panels 

 (PLYSTRAN) in 1976'^. In the Potlatch process, cores with cross-aligned flakes 

 are pressed separately and combined with veneer faces in a second pressing 

 operation (McKean et al. 1975). 



In the South, Biblis and Chiu (1972) described preliminary results with 

 southern pine composite panels, and C.-Y. Hse'^ described composite panels 

 made with faces of southern pine veneer and cores of mixed southern hardwood 

 flakes, fabricated at the Pineville, La. laboratory of the Southern Forest Experi- 

 ment Station. See also Hse (1976). 



In 1973, the American Plywood Association undertook a study of composite 

 panels, financed by the American Plywood Association, the Forest Products 

 Economics and Marketing Research Division of the U.S. Forest Service, and the 

 U.S. Department of Housing and Urban Development (Countryman 1974, 

 1975a). This study developed performance standards for sheathing and for 

 combination subfloor and underlayment (Countryman 1975b) as described in 

 section 24-2 of this chapter and by the American Plywood Association (1980). 

 Flexural design procedures and performance of softwood composite panels 

 tested by the American Plywood Association are reported by Batey et al. (1975) 

 and Lyons et al. (1975). Buckling performance data are given by O'Halloran 

 (1981). 



In 1977 Ellingson Timber Co., Baker, Ore., beganpre-production testing of a 

 composite structural panel in which the core mat is formed between face and 

 back veneers in one operation, with cauls on top and bottom. The binder used is 

 isocyanate. Veneer does not require patching as the core furnish squeezes flush 

 with the caul. By 1978 boards made in the demonstration plant were being sold 

 commercially and plans were underway for expanded production. This one-step 

 softwood composite panel, trade-named ELCOBOARD has a core of hammer- 

 milled planer shavings (Blackman 1978). 



"Personal correspondence with T. W. Vaughan, Elmendorf Research, Inc., August 19, 1980. 



'^Personal correspondence with H. B. McKean, Forest Products Consultant, Lewiston, Idaho, 

 dated August 26, 1980. 



'■^Hse, C.-Y. 1972. Hardwood-flake-core-and-pine-veneer-face panel for exterior use. Paper 

 presented at Southeastern Section meeting of Forest Products Research Society, Pensacola, Fla.. 

 October. 



