Progress And Development Made In The Past 25 Years In The Manufacture and usage of Plywood

By C. W. Buckner, Sales Engineero Harbor Plywood Corporation

In 1922 the n'ord PLYWOOD was not used in connection with laminated rvood. Our Douglas Fir laminated veneers at that time rvere knotvn as panels and were manufactured in a very limited volume and mostly.used for door panels. There n'ere only trvo grad,es, namely, door panels and drawer bottom grades. Practicallv all were 3-p1y and sanded to 3/s" thickness.

In the middle 20's lve began making some other thicknesses and also about this time some /4" rvas made-in 18, 20 and 24 inch widths, 8 foot lengths, bundled and sold as laminated finished lumber. On account of the wide sar,vn lumber in this thickness splitting and checking so easily this wide laminated material became very popular. Also about this time the Eastern furniture manufacturers became interested in panels and many carloads were sold for shelving in kitchen cabinets, table tops and other parts of medium priced furniture. Most of this r,vas ./g,,,, some 3f,,.

Up to this time lumber yards practically ignored this material and vgould not consider stockir-rg it in their yards as they considered the panels, or plyr.vood as it r.vas by this time sometimes called, as encroaching on the lumber dealers' market.

The writer about this time suggested that if the plyrvood plants wouid make a grade of r/"x48"x96" panels, and put it on the market as lvallboard, and get ten per cent of the retail lumber yards to put it in stock, that u'ithin ten years the demand for pl1'u.oocl could be doubled.

This was in1926 in which year the procluction of Douglas Fir Plywood t'as 173 million surfacc feet 3/i,, basis. Bearing out this prediction, I r,vould call attention to tl.re fact that in 1936, ten years later, the production of Douglas Fir Plywood r,vas 700 million surface feet )(," basismore than four times the production in 1926. Procluction continued to increase and in 1946 1,390 million surface feet 3ft" basis was produced-more than eight times the production in 1926, rvhich u'as t.rventy 1'ears pr.ior.

About 1929 and 30 contractors became interested in the use of plywood for concrete form material. The first sizeable order placed for this use was 500,000 feet to be used for forms on the approaches to the Golden Gate Bridge in San Francisco, California. This led to the purchasing of several million feet for this purpose on the Golden Gate and San Francisco-Oakland Bay Bridges.

Abou.t this time foreign countries became interested in Douglas Fir Plywood, particrrlarll' England, Australia, New Zealand and the Scandinavian countries and manv million Teet were shipped abroad.

About 1932 highr,vay engineers became interested in plywood Gussett Plates for r,vooden bridges. The first ones were used on a temporary bridge across the Sacramento River at Sacramento, California. This proved so satisfactory that many wooden bridge designers in California specified plywood Gussett Plates and they were supplied in many thicknesses up to nine inches and over, with eighty-one or more plies. This rvas before resin bonded plywood was developed and great care had been exercised to keep the Gussett Plates well painted.

In 1932 a plyrvood house was built in Oakland, California. This house consisted of living room, kitchen, bedroom, bathroom and sleeping porch. This was perhaps the first time that plywood was used for inside and outside walls. Since that time plywood has become a recognized building material.

The two houses illustrated, the one referred to above built in 1932 and the other a modern house built of plywood about ten years later in Portland, Oregon, which is only one of many thousand modern houses built and being built all over the coun-try, tell the story of the progress and development of plyn'ood better than any tvay I can describe.

In 1935 a Phenolic resin-bonded weather-proof plywood was developed. This revolutionized the usage and demand for plywood. In the past the bonding agent had been vegetable glue, casein glue or soybean glue but none of it n'as entirely rveather-proof and'would delaminate when given sufficient exposure.

The Phei,olic bonded plywood would stand unlimited exposure and still show no delamination and became kno.ivn as exterior plywood. Contractors demanded it for concrete form material, boat building and exterior walls for housing.

When the World's Fairs rvere to be held in New York and Treasure Island, San Francisco, in 1939 it u'as imrnecliatelv decided that exterior plywood rvas the ideal material and specifications rvere drawn accordingly. As a result sixtl'-three buildings at Treasure Island and six buildings at Neu. York l'ere built almost entirelv of plywood.

On the Federal Building at the Treasure Island Fair there 'ivere 48 columns rvhich were built of 47'x72" exterior plyr'vood, 29-p1y, 3" thick. This, so far as the writer knor,vs, is the heaviest exterior plywood ever produced.

Plywood has been used for many years as lining for railway freight cars and as it r,vas not exposed to weather the interior type would stand up for several years without delaminating.

In 1938 the first railway refrigerator car using exterior plywood for outside sheathing, floors, ceilings, bulkheads. and linings, was built in Los Angeles by the Pacific Fruit

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