August 25, 1922 



Hardwood Record — Veneer & Panel Section 



35 



Some Fundamentals of Plywood Construction 



Engineering Research Has Been Instrumental in Establishing to a Certain 



Extent What the Best Methods of Panel Making Are, 



Though Practices Are Not Standardized 



The manufacture of plywood has never become stand- 

 ardized, and thus methods differ somewhat in nearly all 

 plants devoted to turning out this product. This fact, to- 

 gether w^ith the varying qualities of wood, largely ac- 

 counts for the differences that do, and probably always 

 w^ill, exist in panels manufactured by the various concerns. 

 They don't all make panels in the same way and they don't 

 get the same results. How^ever, modern engineering re- 



no harm occasionally to review these fundamentals, for 

 the benefit of those experienced hands at plywood mak- 

 ing w^ho forget and grow careless as w^ell as young men 

 coming up in the industry, either as salesmen or factory 

 employes. "Notes on the Manufacture of Plywood," 

 compiled by the Laboratory and revised up to June, 1 920, 

 will admirably serve this purpose of review of funda- 

 mentals. They follow^: 



U.v L'uani'sy AiiuTU'iili Walnut Maiiutiicturers' Assuciation 

 A Four-Piece Matched Panel of Sliced Veneer from a Cross-Figured Walnut Tree 



search has uncovered a tremendous amount of information 

 concerning the best practices to follow in making ply- 

 wood, and this has already eliminated a great deal of the 

 variation in methods, and w^ill continue to influence the 

 panel making industry toward standardized methods. 



Foremost in the ranks of those who have contributed 

 to this study of the best methods of plywood manufacture 

 is the Forest Products Laboratory at Madison, Wis. The 

 fundamentals of good plywood manufacturing practice, 

 thanks to the observations and experiments of the Labor- 

 atory's experts, are now widely recognized. But it does 



By manufacture of plywood is meant the gluing to- 

 gether of plies of w^ood, usually an odd number, so laid 

 that the grain of alternate layers is approximately at right 

 angles. In three-ply panels the outside plies are referred 

 to as faces and the center ply as a core. In a five-ply con- 

 struction the outside layers are faces, the next two plies 

 in order crossbands and the center ply core. The details 

 of gluing, pressing, and drying plywood are not stand- 

 ardized, but these notes on manufacture are based upon 

 observations of factory practice and upon extensive ex- 

 periments at the Forest Products Laboratory. 



