Del llalle, Kahman & Co. plytllooD, HARDWdtfi- fiinBER, HARDBoARD

New Commerciol Stqndqrd for Hqrdwood Plywood Releosed

Hardwood plywood passed another milestone of progress in October with the U. S. Department of Commerce promulgation of a ner,v Commercial Standard for the material, says Charles E. Close, managing-director of the Hardwood

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Plyu'ood Institute. The new standard, CS 35-56, is based on quality production practices encouraged by the Institute through its qualitv control program backed by testing and research at its Atlanta, Ga., laboratory.

The standard provides minimum specifications for three types of hardwood plywood in four standarcl grades. It also sets forth test requirements and establishes grade names which have been in use by many members of the Hardwood Plywood Institute. "The companies adhering to the Institute's quality control program l'ill use the grades and trademarks on their panels," Close said.

The types of hardwood plywood are distinguished by the difference in performance of the glue bond lletrveen veneers. Grades are based on apPearance factors of the faces or the faces and backs of panels. Types defined in the new standard are classified as Type I, Type II, and Type IIL A special type, called Technical, is also provided' The standard grades are designated Good, Sound, Utility and Backing. A special grade, called Custom, also is provided.

Type I has a fully waterproof bond that rvithstands full weather exposure and is unaffected by micro-organisms. It must pass the rigid dry shear and cyclic boil tests described in the standard. Technical type must fulfill the same requirements.

Type II is produced with a water resistant bond rvhich must retain practically all its strength when subjected to an occasional thorough r,vetting and drying. Specimens must u'ithstand an average of 10 cycles of the 1S-cycle cold soak test outlined in the standard.

T.ype III contains a moisture resistant bond u'hich must retain practically all its strength when occasionally subjected to moisture. It must withstand the 2-cycle cold soak test provided in the standard.

Good grade, recommended for use where a natural finish is desired, has a face made of tight, smoothly cut veneer containing the natural character markings inherent in the