Plywood production: from history to the present time

14.09.2017
The history of plywood as a popular modern building material began more than a century ago. But the first prototypes of wood-layered material found on the territory of modern Egypt date back to 3500 BC. The reasons for the invention of plywood are simple and clear: economic considerations. The carvers replaced the wood, which was in short supply in Ancient Egypt, with a very similar analogue made from glued wood residues.

Subsequently, the Greeks and Romans adopted the plywood production technique from the Egyptians. It is known that in Greece and the Roman Empire, their own timber was in short supply, and imported timber was too expensive. In those distant times, plywood was also included in the list of expensive materials. The reason for the high cost of plywood 2 thousand years ago was explained by manual production and the use of a natural adhesive base - resin for gluing the plates.

Who first created plywood

Plywood is such a familiar material to us that it seems like it has always been there. And that's almost true. The first samples were made back in the 15th century BC: archaeologists found them on the territory of Ancient Egypt. It was a plywood casket made from wooden plates glued together. The inner layers were made of cedar, and the outer layers were made of ebony wood.

Why did the ancient Egyptians resort to such a complex method of making a casket? The thing is that there are very few trees in Egypt. This fact makes wood a very valuable material, and ebony and mahogany wood almost precious. By creating a chest of cedar lined with ebony veneer, the Egyptians reduced its cost. Moreover, the appearance of the created product was as if it was made only from black wood.

Later examples of plywood were also found in the territories of Ancient Rome and Ancient Greece - in these countries wood was also a very valuable material. Furniture and other household items, including home decorations, were made from it. In France, furniture made from plywood sheets appeared in the 16th century. It was decorated with planks carved from valuable wood. When did plywood appear in Russia? It is not known exactly, but we can assume that it was the end of the 18th or the beginning of the 19th century.

Content

• 1. History
• 2 Structural characteristics
• 3 Types 3.1 Softwood plywood
• 3.2 Hardwood plywood
• 3.3 Tropical plywood
• 3.4 Aircraft plywood
• 3.5 Decorative plywood (laminated plywood)
• 3.6 Flexible plywood
• 3.7 Marine plywood
• 3.8 Other plywood
• 3.9 Construction plywood

History of plywood production technology

Until the 18th century, plywood was made by cutting veneer by hand. Natural resins were used to glue it. Producing plywood sheets was a complex process and the product itself was expensive. The first veneer cutting machine was invented by a British mechanical engineer named Samuel Bentham at the end of the 18th century. Since that time, plywood furniture has become cheaper and available to the general population.

The first machine, the operating principle of which is still used today, was created in Russia in 1819. Its inventor was a Briton who lived in our country - Professor Fisher. With the simplification of plywood production, Russia, which has large timber reserves, has become the world leader in its production. Britain took second place.

This is interesting! The first plant for the production of plywood was opened in St. Petersburg in 1894. In Tallinn (Estonia) such a plant was opened in 1889, and in Zelenodolsk (Tatarstan) in 1896.

The sheets were made in various sizes - there was no single standard. It appeared only in 1928. The standard width was 1200 mm and the length was 2400 mm. There was no standard for width, so it could vary between 16-76 mm. The thickness of the modern analogue ranges from 3 to 40 mm. Since then, many brands of plywood have appeared: FK, FSF, laminated, bakelite, etc. And you can buy all these types from us at a low price with delivery in Moscow and Moscow Region.

Structural characteristics

A typical plywood panel has a higher quality face plywood than the core plywood. The main function of the inner layers is to increase the distance between the outer layers, where bending stresses are highest, thereby increasing the panel's flexural resistance. As a result, thicker panels can travel longer distances under the same loads. When bending, the maximum stress occurs in the outer layers, one inch is in tension, the other in compression. The bending stress decreases from a maximum in the face layers to almost zero in the central layer. In contrast, shear stress is higher in the center of the panel and on the outer fibers. In Europe, base plywood can be divided into three main categories: birch plywood (density around 680 kg/m3), mixed plywood (density around 620 kg/m3) and softwood plywood (density 460-520 kg/m3).[9]

Plywood varieties based on the number of knots per 1 sq.m. outer sheet surface

Grade I - practically without defects, partially fused, unfused, falling out knots, holes from them, wormholes with a diameter of no more than 6 mm in the amount of 3 pieces are allowed. per 1 m2, no more than 5 healthy fused knots per 1 m2 with a diameter of up to 15 mm and minor brown veins are also allowed. It can be varnished or not coated with anything. Used to make laminated plywood.

Grade II - partially fused, unfused, falling out knots, holes from them, wormholes with a diameter of no more than 6 mm are allowed in the amount of 6 pieces. per 1 m2, no more than 10 healthy fused knots per 1 m2 with a diameter of up to 25 mm are also allowed, repairing the surface of the sheet is allowed. Knots and open defects are sealed with veneer inserts. Covered with various finishing materials and paints.

Grade III - partially fused, unfused, falling out knots, holes from them, wormholes with a diameter of no more than 6 mm are allowed in the amount of 10 pieces. per 1 m2 of sheet surface, healthy fused knots are also allowed without limiting the number. Intended for the manufacture of structures hidden from external view, various special containers and packaging.

Grade IV - all manufacturing defects are allowed. Partially fused, unfused, falling knots, holes from them, wormholes are allowed in unlimited quantities with a diameter of no more than 40 mm, only good gluing is guaranteed. Used for the manufacture of durable containers and packaging.

Recommendations

1. Collins English Dictionary, 2nd edition, London, 1986, p.1181
2. Cassell's Latin Dictionary, Marchant, J.R.V., & Charles, Joseph F., (Eds.), Revised Edition, 1928, p.421
3. O'Halloran, M.R. "Wood: structural panels"; pp. 917-921 in Andreas Mortensen, ed., The Concise Encyclopedia of Composite Materials
   , Elsevier, 2006.
4. ^ a b
   "Plywood".
   Gail How Products Are Made
   . Gale Group Inc. Retrieved November 26, 2013.
5. "Nobel plywood." Retrieved 2018-04-03.
6. "Deruler." Le Robert Historique de la langue française
   . Dictionaries Robert. Retrieved November 26, 2013.
7. "Plywood". Columbia Encyclopedia
   . Retrieved November 26, 2013.
8. Muller, Norman E. (1992). "An early example of a plywood stand ready to be painted." Journal of the American Institute of Conservation
   .
   31
   (2):257–260. Doi:10.2307/3179496. JSTOR 3179496.
9. https://www.woodproducts.fi/content/plywood
10. O'Halloran, p. 221.
11. Handbook of Finnish Plywood
    , Finnish Forest Industry Federation, 2002, ISBN 952-9506-63-5 "Archive copy" (PDF). Archived from the original (PDF) on 2007-09-27. Retrieved 2007-09-27.CS1 maint: zipped copy as title (link)
12. "Lauan (Shorea spp.)." www.rainforestrelief.org
    . Received 2019-11-15.
13. Winchester, Jim. "Hughes N-4" Spruce Goose ". Concept Aircraft: Prototypes, X-Planes, and Experimental Aircraft
    . Kent, UK: Grange Books plc., 2005. ISBN 978-1-59223-480-6 p. 113.
14. Marshfield women remember building engineering marvels Archived 2014-12-17 in the Wayback Machine, Marshfield News Herald
15. https://somma.vn/construction-plywood/
16. https://goldwoodply.com/boat.php
17. Engineered Wood Products Association of Australasia. (PDF). Retrieved February 10, 2012.
18. Pro Woodworking Tips.com Archived 2010-10-05 on the Wayback Machine. Pro Woodworking Tips.com. Retrieved February 10, 2012.
19. https://goldwoodply.com/goldwood.php
20. Metric Conversions, Government of Canada Publication Archived 2010-02-16 at the Wayback Machine. (PDF). Retrieved February 10, 2012.
21. Joyce, Ernes. 1970 Furniture Making Techniques
    . London: B. T. Batsford Limited.

Plywood grades by water resistance

• FC - plywood is glued with urea resin. For indoor use;
• FSF - plywood is glued together with phenolic resin. For use both indoors and outdoors;
• FB – bakelite plywood – is impregnated with bakelite varnish and then glued together. Can be used in tropical climates, aggressive environments and sea water.
• FOF - laminated plywood - is birch plywood lined with a film coating (paper impregnated with synthetic resin) on one or both sides.

Ratings

Grading guidelines vary depending on the country of origin. The most popular standards are British Standard (BS) and American Standard (ASTM). Joyce (1970), however, provides some general guidance on grading rules:[21]

JPIC Standards

Application[ | ]

Homemade all-terrain vehicle "Karakat" with a plywood body
Construction

• Insulating products in electrical engineering.
• In the aviation industry (see Delta wood).
• For making furniture.
• As a base for parquet and parquet boards.
• In shipbuilding for stern tube bearings, bushings and liners for conventional bearings (anti-friction, self-lubricating material), gears and other machine parts (structural material)
• production of microfluidic chips[1]

A little about plywood storage

Manufacturers try to pack sheets of plywood into stacks that form bags, and tie everything together with strong rope. The material should be stored strictly horizontally on special pallets.

The number of sheets in such a package may vary, and it will depend on the thickness of the sheets in the package, as well as other factors. In the plywood storage room, certain conditions must be met, namely that the air humidity should be no more than 80%, the temperature range, which is allowed from -40 to +50 degrees. Plywood must be protected from the effects of precipitation, as well as from direct rays of sunlight.

In addition, there must be ventilation. Subject to all the conditions listed above, plywood can be stored without loss of characteristics for any time.

Interestingly, plywood, which is a component of furniture, was actually previously used for more than just this. During the Second World War, it was used in aviation, and the material was used to make the skin, as well as the fuselage of aircraft. And during times of material shortages, such building material successfully played the role of fuel tanks.

Applications

Plywood is used in many applications where high-quality and highly durable sheet material is required. Quality in this context means resistance to cracking, breaking, shrinking, twisting and warping.

Exterior plywood is suitable for outdoor use, but since moisture affects the strength of the wood, optimal performance is achieved at a relatively low moisture content. Sub-zero conditions do not affect the dimensional or strength properties of plywood, making some special applications possible.

Plywood is also used as an engineering material for stress sheathing applications. It has been used for marine and aviation applications since World War II. Most notable are the British de Havilland Mosquito bomber, with a birch plywood fuselage between a balsa core and extensive use of plywood for the wings. Plywood was also used to make the hulls of the die-hard Motor Torpedo Boats (MTB) and Motor Gun Boats (MGB) built by the British Motor Boat Company and Vospers. Plywood is currently being successfully used in stressed skin applications.[ citation needed

] American designers Charles and Ray Eames are famous for their plywood furniture, as are Finnish architect Alvar Aalto and his firm Artek, while Phil Bolger designed a wide range of boats built primarily from plywood.
Jack Koepper from Cape Town developed the plywood Dabchick dinghy, which as of 2015[Update] is still sailed by a large number of teenagers. Detrola Radio Model 579 (1946), made from plywood
Plywood is often used to create curved surfaces because it bends easily with the grain. Skateboard ramps often use plywood as the top smooth surface over curved curves to create a transition that can mimic the shapes of ocean waves.

Application of softwood plywood

Typical end uses for spruce plywood:

• Floors, walls and roofing in houses
• Wind strut panels
• Interior car body work
• Packages and boxes
• Fencing

There are coatings that mask the noticeable fiber structure of spruce plywood. There are some end uses for this coated plywood where reasonable strength is required, but the lightness of spruce is an advantage, such as:

• Concrete formwork panels
• Ready-to-paint construction surfaces

Hardwood plywood appliques

Phenolic Resin Film Faced Plywood is commonly used as a ready-to-install component, such as:

• Panels in concrete formwork systems
• Floors, walls and roofs in vehicles
• Container floors
• Floors subject to heavy wear and tear in various buildings and factories
• Construction Materials

("Wire" or other printing styles are available for better adhesion)
Birch plywood is used as a construction material in specialty applications such as:

• Wind turbine blade
• Insulation boxes for liquefied natural gas (LNG) carriers

The smooth surface and precise thickness combined with the strength of the material make birch plywood a suitable material for many special purposes, such as:

• High quality speakers
• Die cutting boards
• Load-bearing structure for parquet
• Play equipment
• Furniture
• Signs and barriers for demanding outdoor advertising
• Musical instruments
• Sport equipment

Tropical Plywood Applications

Tropical plywood is widely available from the Southeast Asian region, mainly from Malaysia and Indonesia.

• Regular plywood
• Concrete panel
• Subfloor
• Structure panel
• Container flooring
• Laminate board
• Laminated timber (LVL)

Notes[ | ]

1. Grigory Kopiev.
   
   (unspecified)
   was made from birch plywood . nplus1.ru. Access date: November 28, 2022.
2. Chinese plywood: the difference between Russian and plywood from China (Russian). Chinese plywood: the difference between Russian and Chinese plywood
   . Access date: March 15, 2022.
3. Chinese and Russian laminated plywood (Russian). fanera-bazar.ru
   . Access date: March 15, 2022.
4. Laminated laminated wood. Terms and Definitions. GOST 15812-87.

An excerpt characterizing Plywood

Again everything fell silent, but Prince Andrei knew that she was still sitting here, he sometimes heard quiet movements, sometimes sighs. - Oh my god! My God! what is this! – she suddenly screamed. - Sleep like that! – and slammed the window. “And they don’t care about my existence!” thought Prince Andrei as he listened to her conversation, for some reason expecting and fearing that she would say something about him. - “And there she is again! And how on purpose!” he thought. In his soul suddenly arose such an unexpected confusion of young thoughts and hopes, contradicting his whole life, that he, feeling unable to understand his condition, immediately fell asleep. The next day, having said goodbye to only one count, without waiting for the ladies to leave, Prince Andrei went home. It was already the beginning of June when Prince Andrei, returning home, again drove into that birch grove in which this old, gnarled oak had struck him so strangely and memorably. The bells rang even more muffled in the forest than a month and a half ago; everything was full, shady and dense; and the young spruces, scattered throughout the forest, did not disturb the overall beauty and, imitating the general character, were tenderly green with fluffy young shoots. It was hot all day, a thunderstorm was gathering somewhere, but only a small cloud splashed on the dust of the road and on the succulent leaves. The left side of the forest was dark, in shadow; the right one, wet and glossy, glistened in the sun, slightly swaying in the wind. Everything was in bloom; the nightingales chattered and rolled, now close, now far away. “Yes, here, in this forest, there was this oak tree with which we agreed,” thought Prince Andrei. “Where is he,” Prince Andrei thought again, looking at the left side of the road and without knowing it, without recognizing him, he admired the oak tree that he was looking for. The old oak tree, completely transformed, spread out like a tent of lush, dark greenery, swayed slightly, swaying slightly in the rays of the evening sun. No gnarled fingers, no sores, no old mistrust and grief - nothing was visible. Juicy, young leaves broke through the tough, hundred-year-old bark without knots, so it was impossible to believe that this old man had produced them. “Yes, this is that same oak tree,” thought Prince Andrei, and suddenly an unreasonable, spring feeling of joy and renewal came over him. All the best moments of his life suddenly came back to him at the same time. And Austerlitz with the high sky, and the dead, reproachful face of his wife, and Pierre on the ferry, and the girl excited by the beauty of the night, and this night, and the moon - and all this suddenly came to his mind. “No, life is not over at the age of 31, Prince Andrei suddenly finally, permanently decided. Not only do I know everything that is in me, it is necessary for everyone to know it: both Pierre and this girl who wanted to fly into the sky, it is necessary for everyone to know me, so that my life does not go on for me alone So that they don’t live so independently of my life, so that it affects everyone and so that they all live with me!” Returning from his trip, Prince Andrei decided to go to St. Petersburg in the fall and came up with various reasons for this decision. A whole series of reasonable, logical arguments why he needed to go to St. Petersburg and even serve were ready at his service every minute. Even now he did not understand how he could ever doubt the need to take an active part in life, just as a month ago he did not understand how the thought of leaving the village could have occurred to him. It seemed clear to him that all his experiences in life would have been in vain and would have been meaningless if he had not applied them to action and taken an active part in life again. He did not even understand how, on the basis of the same poor reasonable arguments, it had previously been obvious that he would have humiliated himself if now, after his life lessons, he again believed in the possibility of being useful and in the possibility of happiness and love. Now my mind suggested something completely different. After this trip, Prince Andrei began to get bored in the village, his previous activities did not interest him, and often, sitting alone in his office, he got up, went to the mirror and looked at his face for a long time. Then he turned away and looked at the portrait of the deceased Lisa, who, with her curls whipped up a la grecque [in Greek], tenderly and cheerfully looked at him from the golden frame. She no longer spoke the same terrible words to her husband; she simply and cheerfully looked at him with curiosity. And Prince Andrei, clasping his hands back, walked around the room for a long time, now frowning, now smiling, reconsidering those unreasonable, inexpressible in words, secret as a crime thoughts associated with Pierre, with fame, with the girl on the window, with the oak tree, with female beauty and love that changed his whole life. And at these moments, when someone came to him, he was especially dry, strictly decisive and especially unpleasantly logical. “Mon cher, [My dear,],” Princess Marya would say when entering at such a moment, “Nikolushka can’t go for a walk today: it’s very cold.” “If it were warm,” Prince Andrei answered his sister especially dryly at such moments, “then he would go in just a shirt, but since it’s cold, we need to put warm clothes on him, which were invented for this purpose.” This is what follows from the fact that it’s cold, and not like staying at home when the child needs air,” he said with particular logic, as if punishing someone for all this secret, illogical inner work that was happening in him. Princess Marya thought in these cases about how this mental work dries out men. Prince Andrey arrived in St. Petersburg in August 1809. This was the time of the apogee of the glory of the young Speransky and the energy of the revolutions he carried out. In this very August, the sovereign, while riding in a carriage, fell out, injured his leg, and remained in Peterhof for three weeks, seeing daily and exclusively with Speransky. At this time, not only two so famous and alarming decrees were being prepared on the abolition of court ranks and on examinations for the ranks of collegiate assessors and state councilors, but also an entire state constitution, which was supposed to change the existing judicial, administrative and financial order of government of Russia from the state council to the volost board. Now those vague, liberal dreams with which Emperor Alexander ascended the throne were being realized and embodied, and which he sought to realize with the help of his assistants Chartorizhsky, Novosiltsev, Kochubey and Strogonov, whom he himself jokingly called comite du salut publique. [Committee of Public Safety.] Now everyone has been replaced by Speransky on the civil side and Arakcheev on the military side. Prince Andrei, soon after his arrival, as a chamberlain, came to the court and left. The Tsar, having met him twice, did not honor him with a single word. It always seemed to Prince Andrei that he was antipathetic to the sovereign, that the sovereign was unpleasant about his face and his whole being. In the dry, distant look with which the sovereign looked at him, Prince Andrei found confirmation of this assumption even more than before. The courtiers explained to Prince Andrey the sovereign's lack of attention to him by the fact that His Majesty was dissatisfied with the fact that Bolkonsky had not served since 1805. “I myself know how much we have no control over our likes and dislikes,” thought Prince Andrei, and therefore there is no need to think about personally presenting my note on the military regulations to the sovereign, but the matter will speak for itself.” He conveyed his note to the old field marshal, a friend of his father. The field marshal, having appointed an hour for him, received him kindly and promised to report to the sovereign. A few days later it was announced to Prince Andrey that he had to appear before the Minister of War, Count Arakcheev. At nine o'clock in the morning, on the appointed day, Prince Andrei appeared in the reception room of Count Arakcheev. Prince Andrei did not know Arakcheev personally and had never seen him, but everything he knew about him inspired him with little respect for this man. “He is the Minister of War, the confidant of the Emperor; no one should care about his personal properties; he was instructed to consider my note, therefore he alone can give it a go,” thought Prince Andrei, waiting among many important and unimportant persons in the reception room of Count Arakcheev. Prince Andrei, during his mostly adjutant service, saw a lot of adopted important persons and the different characters of these adopted ones were very clear to him. Count Arakcheev had a very special character in his reception room. A sense of shame and humility was written on the unimportant faces waiting in line for an audience in Count Arakcheev’s reception room; on the more official faces one common feeling of awkwardness was expressed, hidden under the guise of swagger and ridicule of oneself, one’s position and one’s expected face. Some walked thoughtfully back and forth, others laughed in whispers, and Prince Andrei heard the sobriquet [mocking nickname] of Andreich’s forces and the words: “uncle will ask,” referring to Count Arakcheev. One general (an important person), apparently offended that he had to wait so long, sat crossing his legs and smiling contemptuously at himself. But as soon as the door opened, all the faces instantly expressed only one thing - fear. Prince Andrei asked the duty officer to report about himself another time, but they looked at him with ridicule and said that his turn would come in due time. After several persons were brought in and out by the adjutant from the minister’s office, an officer was let in through the terrible door, striking Prince Andrei with his humiliated and frightened appearance. The officer's audience lasted a long time. Suddenly, peals of an unpleasant voice were heard from behind the door, and a pale officer, with trembling lips, came out of there, grabbed his head, and walked through the reception area. Following this, Prince Andrei was led to the door, and the attendant said in a whisper: “to the right, to the window.” Prince Andrei entered a modest, neat office and at the desk saw a forty-year-old man with a long waist, a long, short-cropped head and thick wrinkles, with frowning eyebrows over brown, dull green eyes and a drooping red nose. Arakcheev turned his head towards him, without looking at him. -What are you asking for? – asked Arakcheev. “I don’t... please, your Excellency,” said Prince Andrei quietly. Arakcheev's eyes turned to him. “Sit down,” said Arakcheev, “Prince Bolkonsky?” “I’m not asking for anything, but the Emperor deigned to forward the note I submitted to your Excellency...” “Please see, my dear, I read your note,” Arakcheev interrupted, only saying the first words affectionately, again without looking him in the face and becoming more and more depressed. and more in a grumpily contemptuous tone. – Are you proposing new military laws? There are many laws, and there is no one to enforce the old ones. Nowadays all laws are written; it is easier to write than to do. “I came by the will of the Emperor to find out from your Excellency what course you intend to give to the submitted note?” - Prince Andrey said politely. “I have added a resolution to your note and forwarded it to the committee.” “I don’t approve,” said Arakcheev, getting up and taking a paper from the desk. - Here! – he handed it to Prince Andrey. On the paper across it, in pencil, without capital letters, without spelling, without punctuation, was written: “unfoundedly composed as an imitation copied from the French military regulations and from the military article without the need of retreating.” – Which committee was the note sent to? - asked Prince Andrei. - To the committee on military regulations, and I submitted a proposal to enroll your honor as a member. Just no salary. Prince Andrei smiled. - I don’t want to. “Without a salary as a member,” Arakcheev repeated. - I have the honor. Hey, call me! Who else? - he shouted, bowing to Prince Andrei. While awaiting notification of his enrollment as a member of the committee, Prince Andrei renewed old acquaintances, especially with those persons who, he knew, were in force and could be needed by him. He now experienced in St. Petersburg a feeling similar to what he had experienced on the eve of the battle, when he was tormented by a restless curiosity and irresistibly drawn to higher spheres, to where the future was being prepared, on which the fate of millions depended. He felt from the embitterment of the old people, from the curiosity of the uninitiated, from the restraint of the initiated, from the haste and concern of everyone, from the countless number of committees, commissions, the existence of which he learned again every day, that now, in 1809, was being prepared here in St. Petersburg, some kind of huge civil battle, the commander-in-chief of which was a person unknown to him, mysterious and who seemed to him a genius - Speransky. And the most vaguely known matter of transformation, and Speransky, the main figure, began to interest him so passionately that the matter of military regulations very soon began to pass into a secondary place in his mind. Prince Andrei was in one of the most favorable positions to be well received into all the most diverse and highest circles of the then St. Petersburg society. The party of reformers cordially received and lured him, firstly because he had a reputation for intelligence and great reading, and secondly because by his release of the peasants he had already made himself a reputation as a liberal. The party of dissatisfied old men, just like their father’s son, turned to him for sympathy, condemning the reforms. Women's society, society, welcomed him cordially, because he was a groom, rich and noble, and almost a new face with the aura of a romantic story about his imaginary death and the tragic death of his wife. In addition, the general voice about him from everyone who knew him before was that he had changed a lot for the better in these five years, had softened and matured, that there was no former pretense, pride and mockery in him, and there was that calmness that purchased over the years. They started talking about him, they were interested in him and everyone wanted to see him. The next day after visiting Count Arakcheev, Prince Andrei visited Count Kochubey in the evening. He told the count his meeting with Sila Andreich (Kochubey called Arakcheev that way with the same vague mockery that Prince Andrei noticed in the reception room of the Minister of War). - Mon cher, [My dear,] even in this matter you will not bypass Mikhail Mikhailovich. C'est le grand faiseur. [Everything is done by him.] I will tell him. He promised to come in the evening... - What does Speransky care about military regulations? - asked Prince Andrei. Kochubey smiled and shook his head, as if surprised at Bolkonsky’s naivety. “He and I talked about you the other day,” Kochubey continued, “about your free cultivators...” “Yes, it was you, prince, who let your men go?” - said the old man from Catherine, turning contemptuously at Bolkonsky. “The small estate did not bring in any income,” Bolkonsky answered, so as not to irritate the old man in vain, trying to soften his act in front of him. “Vous craignez d'etre en retard, [Afraid of being late," the old man said, looking at Kochubey. “There’s one thing I don’t understand,” the old man continued, “who will plow the land if you give them the freedom?” It is easy to write laws, but difficult to govern. It’s the same as now, I ask you, Count, who will be the head of the wards when everyone has to take exams? “Those who will pass the exams, I think,” answered Kochubey, crossing his legs and looking around. “Here is Pryanichnikov, who works for me, a nice man, a golden man, and he is 60 years old, will he really go to the exams?...

Literature[ | ]

• Grigoriev M. A.
  Materials science for joiners, carpenters and parquet workers: A textbook for vocational schools. - M.: Higher School, 1989. - 223 p. — 100,000 copies. — ISBN 5-06-000345-0.
• GOST 3916.1-2018 General purpose plywood with outer layers of hardwood veneer.
• GOST 3916.2-2018 General purpose plywood with outer layers of softwood veneer.
• GOST 8973-2018 Plywood boards. Specifications
• GOST 11539-2014 Bakelized plywood. Specifications
• GOST 13913-78 (GOST for Laminated wood plastics (chipboard))
• GOST 102-75 Aviation birch plywood.
• GOST B-226-41 Delta wood for aviation.
• Plywood // Commodity Dictionary / I. A. Pugachev (editor-in-chief). - M.: State Publishing House of Trade Literature, 1961. - T. IX. - Stb. 8-13