Plywood

==History==
The ancient Egyptians and Greeks cut wood thinly and [[glue]]d it together in layers with the grain in perpendicular directions as fine wood was in short supply. This is believed to have been done purely for cosmetic and economical purposes but it turned out to be a great alternative to pure wood as it reduced flex, making it a versatile building material.
<ref>O'Halloran, M.R., "[https://books.google.com/books?id=zs_lGeGsuaAC&dq=ancient+Greek+plywood&pg=PA917 Wood: Structural Panels]"; pp. 917-921 in Andreas Mortensen, ed., ''Concise Encyclopedia of Composite Materials'', Elsevier, 2006.</ref> 

In 1797 [[Samuel Bentham]] applied for patents covering several machines to produce veneers. In his patent applications, he described the concept of laminating several layers of veneer with glue to form a thicker piece – the first description of what we now call plywood.<ref name="Plywood">{{cite web|title=Plywood|url=http://www.answers.com/topic/plywood|work=Gale's How Products are Made|publisher=The Gale Group Inc.|access-date=26 November 2013}}</ref>   Bentham was a British naval engineer with many shipbuilding inventions to his credit. Veneers at the time of Bentham were [[flat sawn]], [[rift sawing|rift sawn]] or [[quarter sawn]]; i.e. cut along or across the log manually in different angles to the grain and thus limited in width and length.{{citation needed|date = November 2019}}

About fifty years later [[Immanuel Nobel]], father of [[Alfred Nobel]], realized that several thinner layers of wood bonded together would be stronger than a single thick layer of wood. Understanding the industrial potential of laminated wood, he invented the [[Lathe#Rotary lathes|rotary lathe]].<ref>{{Cite web|url=http://thetimberpanel.blogspot.com/2013/09/nobel-plywood.html|title=Nobel Plywood|language=en|access-date=2018-04-03}}</ref>

There is little record of the early implementation of the rotary lathe and the subsequent commercialization of plywood as we know it today, but in its 1870 edition, the French dictionary ''Robert'' describes the process of rotary lathe veneer manufacturing in its entry ''Déroulage''.<ref>{{cite web|title=Dérouler|url=http://historique.fracademic.com/18379d%C3%A9rouler|work=Le Robert Historique de la langue française|publisher=Dictionnaires Robert|access-date=26 November 2013|archive-date=2 December 2013|archive-url=https://web.archive.org/web/20131202224050/http://historique.fracademic.com/18379d%C3%A9rouler|url-status=dead}}</ref>  One can thus presume that rotary lathe plywood manufacturing was an established process in France in the 1860s. Plywood was introduced into the United States in 1865<ref>{{cite encyclopedia|title=Plywood|url=http://www.answers.com/topic/plywood|encyclopedia=Columbia Encyclopedia|access-date=26 November 2013}}</ref>  and industrial production there started shortly after. In 1928, the first standard-sized 4&nbsp;ft by 8&nbsp;ft (1.22 m by 2.44 m) plywood sheets were introduced in the United States for use as a general building material.<ref name="Plywood"/>

Artists use plywood as a support for easel paintings to replace traditional canvas or cardboard. Ready-made ''artist boards'' for oil painting in three-layered plywood (3-ply) were produced and sold in New York as early as 1880.<ref>{{cite journal|last=Muller|first=Norman E.|title=An early example of a plywood support for painting|journal=Journal of the American Institute for Conservation|volume=31|issue=2|pages=257–260|jstor=3179496|year=1992|doi=10.2307/3179496}}</ref>

There were experiments with gluing plywood with phenolic resins, mostly in the form of an alcoholic solution or powder, which, however, did not provide sufficient accuracy of application. Around 1930 a dry process of gluing veneers to plywood with phenolic resin in form of a [[Tego film|film]] has begun to spread in the production of waterproof plywood.<ref>{{Cite journal |last=Sorensen |first=Ray |date=1934-01-01 |title=Dry Film Gluing in Plywood Manufacture |url=https://cybra.lodz.pl/Content/6335/WDI_56_1.pdf |journal=Journal of Fluids Engineering |language=en |volume=56 |issue=1 |pages=37–46 |doi=10.1115/1.4019652 |issn=0097-6822}}</ref><ref>{{Cite journal |last=Klein |first=Louis |date=1941-08-01 |title=Phenolic Resins for Plywood |url=https://pubs.acs.org/doi/abs/10.1021/ie50380a005 |journal=Industrial & Engineering Chemistry |language=en |volume=33 |issue=8 |pages=975–980 |doi=10.1021/ie50380a005 |issn=0019-7866}}</ref>