2654 Chapter 22 



Coast company has had considerable success in marketing such a product made 

 from western red cedar {Thuja plicata Donn ex. D. Don). 



SPECIFICATIONS AND STANDARDS 



Defects and grades of trees and logs, and the veneer cut from them are 

 described in sections 12-5, 12-6, and 12-7. This subsection is concerned with 

 product standards for hardwood decorative plywood, block flooring, and stock 

 panels. 



Decorative plywood. — Voluntary Product Standard PS 51-71 (U.S. Depart- 

 ment of Commerce 1972) establishes marketing classifications, quality criteria, 

 test methods, definitions, and grade-marking and certification practices for 

 plywood produced mainly from hardwoods. Hardwood plywood panels are 

 constructed with an odd number of plys to produce a balanced panel; all inner 

 plys, except the core or center ply occur in pairs having the same thickness and 

 grain direction (fig. 22-47). Face veneers may be randomly matched or specified 

 in a variety of patterns (fig. 22-48). Veneers are graded as Premium, Good, 

 Sound, Utility, Backing, or Specialty. 



Premium grade veneer is smooth, tight-cut, and full length. When used as a 

 face, and when it consists of more than one piece it is edge-matched with tight 

 joints, in patterns variable among species and with veneer cutting technique as 

 specified in the grading rules. Characteristics permitted are defined in the grad- 

 ing rules but in general include small burls, occasional pin knots, color streaks or 

 spots, and inconspicuous small patches; however, knots (other than pin knots), 

 worm holes, rough-cut veneer, splits, shake, and decay are not permitted. 

 Sapwood is not permitted in some classifications, e.g., sweetgum selected for 

 red color, or plain- and rift-sliced oak. 



Good grade veneer is smooth, tight-cut, and full-length. When used as a face 

 and when consisting of more than one piece, the edge joints are tight but need not 

 be matched for color or grain; sharp contrasts, however, in grain, figure, or 

 natural characteristics are not permitted between adjacent pieces of veneer. 

 Characteristics allowed are defined in the grading rules, but in general include 

 small burls, pin knots, color streaks or spots, inconspicuous patches and usual 

 characteristics inherent in the species; however, knots (other than pin knots), 

 wormholes, rough-cut veneer, splits, shake, and decay are not permitted. 



Sound grade veneer is free of open defects, but need not be matched for grain 

 or color (table 22-16). Utility grade and Backing grade veneer permit some 

 open defects as specified in table 22-16. Specialty grade veneer can have 

 characteristics as agreed upon between buyer and seller; wormy, birdseye, or 

 pecky characteristics appropriate for wall panelling generally fall in this 

 category. 



Glue bonds in hardwood veneer are classified by their water resistance. 

 Technical Type and Type I plywoods are most resistant (levels of joint shear 

 strength and integrity after a severe cyclic-boil test are specified). Type II 



