YEAR.3

Circular Plywood

Plywood Hallway

A Quarter o( a Century in Plywood

(Continued from Page, 54) when set, formed a permanent bond impervious to rvater, weather and other conditions.

The machine is called a "hot press" and resembles a giant accordian stretched out and stood on end. The panels are placed in the openings and the plates come together with a pressure of about 200 pounds per square inch while steam heat of from 2& to 285 degrees pours through the plate walls to speed the bonding process. Pressing time is f.rom 4 to 10 minutes. Phenol formaldehyde resin adhesives, which are ,completely waterprooT, are used to bond Exterior type plywood. Although spread on the veneers (in the manufacturing process) as a liquid, when heat and pressure are applied, the adhesives between the plies set iir a permanent waterproof bond akin to bakelite and stronger than the wood itself.

Since 1928 the plywood industry has maintained an association almost continuously to promote the use of its product although the sale has remained directly the activity of the manufacturers. The Douglas Fir Ply.ivood Association as it is today was formed in 1933. Today the industry through the trade association has an efficient staff to do grade inspection, promotion and research.

Although the industry can not filI the demand for plywood today, it is, through the association, accumulating much information for furthering the use of plywood when it is again plentiful. This is particularly true in the agricultural field. There has been a great deal accomplished through the cooperation of universities and colleges. During the past five vears 207 projects have been initiated at 35 state colleges by agricultural engineers for the industry. Plyrvood engineers have worked directly with agricultural leaders at the schools in perfecting the designs, erecting the structures and observing their performance.

The industry also maintains a stiff of inspectors who operate through the association. They circulate among the various plants to revieu' the manufacturing processes, cooperate lvith the mill inspection departments and collect random san.rples of plyn'ood for testing at the industry laboratory at Tacoma, \Vash. These samples are tested to destruction in the laboratory to determine the effectivqness of adhesil'es under varying gonditions.

It is tl-re purpose of these laboratory studies to assure the ultimate user of Douglas fir plywood that the panels are of uniform quality and meet the rigid requirements set forth in U.S. Department of Commerce Commercial Standard CS45-45 applying to the material. The first commercial standard for fir plywood .r.vas established in 1932; since then five revisions have been effected with the current standard established January 27,1945. The standard sets forth the grades and types of fir plywood that are manufactured and lists the testing procedure to be followed to determine that each panel conforms completely to its grade.

In the fnterior type there are three grades; Plypanel SolS for interior walls. Plypanel So2S for applications where both sides must be finished such as cabinet doors. Plyscord for sheathing.

Exterior or waterproof type is also produced in several appearance grades. Plyform is an intermediate type made especially for construction of multiple-use concrete forms.

During the war much research was geared to the immediate needs of the armed- services. An example is the series of experiments recorded to answer the questions of the U.S. Army Engineers as to the resistance of adhesives in Exterior type plywood to oil, gasoline and salt water. The laboratory staff developed tests for adhesives and resin sealers used for a special grade of plywood introduced to meet specific war needs and manufactured only for the Army and Navy.

Recent projects developed data on nail holding qualities of the panels, and tests have been made on structural characteristics of built-up box girders and'I-beams. Designs for shipping cases have been tested.

The plywood industry has continued, through its trade association, to promote Douglas fir plywood. This has been done through advertising and literature. The activity has continued, although there was very tittle plywood for civilian use, to promote the building of plywood boats, farm structures, concrete forms, houses and office buildings. Also for use in store displays and in industrial utilization. Large quantities of literature is being mailed out constantly in answer to requests and several motion pictures are available to lumber dealers, architects, builclers and plywood users,

Another milestone in the development of the plywood industry of the Pacific Northwest was the establishment of the Plywood Research Foundation at Tacoma in 1945. It is a separate organization supported entirely by the plywood producers who already have appropriated more than half a million dollars for its operation and have pledged continued support. Its purpose, separate and apart from the testing and product development activities of the laboratory of the Douglas Fir Plywood Association are:

1. To develop means of using waste wood material resulting from present processing at plywood factories and in the forests.

2. To produce new products which the plywood factories can manufacture in addition to their present panels.

3. To improve plyrvood through chemical means.

4. To improve the production and properties of Douglas fir plywood through improvement in processing and manufacturing equipment.

Unfolding the history of Douglas fir plywood has been at top tempo for the past ten years. For during this period, it has been firmly established as the material that does more different jobs than any other; its spectacular war role made it ready for added construction and industrial applications in the years ahead.

From Lcrrue Woodson

"The good things of life are often passed by lightly, and your good magazine comes under that category. At any rate, Jack, we enjoy your publication, your excellent editorials, and appreciate the fine work you are doing. Every good wish for your continued success." L. J. Wogdson, Nicolai Door Sales Co., San Francisco.

With Exterior'tYPe Douglns fi, PIYwood siiling, this home exetnplifies one ol the unusual methoils ol PIY' uooil application. Battens couered the joints, iliuid'ing the outsid'e walls in modular uertical sections. Interior' type plyuooil uas used' on the attrac' tiae tlinette uall shown aboae,

PIYWOOD'S,UIANY ADVANTAGES

KEEP DEMANDS GREATER THAN PRESENT SUPPIIES

Douglas fir plywood production is greater now-than in -prewai years. Today's demand, however, is ulprecedentedand raw material availability is the control' lins factor in obtaining higher output. This uneven demand-supply ratio naturallv means that Plywood maY not alwavs'be readilv obtainable at any given time and place' KeeP in touch irith vour regulai source'of supply as to price and-delivery information. For technical data, write the Douglas Fir Plywood Association, Tacoma 2, Washington.

One of Nine Built in '38 ond '39 . . . Feotured Nqtionolly in'471

s.rys tItHIS attractive modern Portland, Oregon, home was fea' I t,rred this year by rtwo national publications and termed by one 'oA House of Great Merit" yet it was built not this year or lasi, but in 1939! One of a group of nine which utilized Douglas fir plywood for exterior walls and interior detail, it features an advanced design whioh keeps it a oodis' play home," even after six years. The builder' Burt Smith of br*.go, Oregon, says: 'oThe houses were built in 1938 and 1939 and the plywood is more than ojust satisfactory'' There is a definite labor saving in application. The insulition value is good. These houses have had no repair or maintenance, while other houses built by me the same year have had major repairs to exterior finishes."

IARGE,

Plywood Subfloors

Plywood for Boats