Today the construction market is filled with a variety of materials that are used directly for the construction of buildings and finishing work. Multi-layer plywood, consisting of several sheets of peeled veneer, is in great demand among a wide range. The minimum number of layers is 3, but in general, there can be any number of them, but at the same time it is always odd.
Note! Due to the variety of material in thickness, it can be found in any application both in creativity and in construction.
Features of production
They began to produce it a long time ago, and with the development of industry and the creation of new adhesives, indicators improved. As a result, the use in the construction business is actively increasing, in contrast to solid wood, which has the properties of deformation. In this case, deformation can occur both along the fibers and across. Plywood, in turn, is completely devoid of all flaws.
Such indicators were achieved due to a special production technology. Each layer of material is applied in such a way that the fibers lie perpendicular to each other. Due to this, there is no deformation and susceptibility to curvature. Due to the fact that an odd number of layers are made, maximum balance is achieved. There are options when plywood can have an even number of layers. In this case, the middle two layers lie against each other in the parallel direction of the fibers. Therefore, we can conclude that the sheet should be symmetrical about the middle layer or axis.
The front and back sides are easy to distinguish, since the first is covered with better quality veneer. Additionally, there is a marking with a special cipher, with which you can find out belonging to a certain variety.
Main varieties
Multi-layer plywood has its own qualifications. It is very important to consider it when choosing material for a particular case. To determine the grade, it is worth paying attention to indicators such as the presence of wormholes, cracks, knots, shells, stratification of sheets.
- grade I (1 or A) excludes all possible defects, the tolerance is the presence of a wormhole whose diameter does not exceed 6 mm, 5 intergrown knots per 1 square meter. This grade is chosen for laminate coating.
- grade II (2 or B) is used as a finishing material to be subsequently varnished or painted. The presence of 6 wormholes with a diameter of no more than 6 mm per square meter is allowed. The presence of minor brown veins is also considered a tolerance.
- grade III (3 or C) the number of wormholes per square meter increases to 10, without limitation there may be intergrown knots.
- grade IV (4 or D), the quality of veneer can be very different, the presence of various production defects is considered a tolerance. Only a high-quality gluing is required.
Main settings
Versatility comes from performance. The thickness of modern plywood can be quite different. This makes it possible to choose the most suitable option. Multi-layer plywood, the dimensions of which have certain standards, is available for sale to every customer.
In general, the minimum thickness is 3 mm, and the maximum is 30 mm.
Moisture resistance and other features
Any modern plywood is multilayer moisture resistant. The level of moisture resistance directly depends on the adhesive composition that is used during production. Today there are several types of moisture resistance:
- FC - for its production, urea resins are used as an adhesive. It is recommended to use such building material indoors with a normal level of humidity and without sudden changes in temperature conditions. This plywood is also used for the production of cabinet and upholstered furniture.
- FSF - multi-layer, high moisture resistance. Phenol-formaldehyde resin is used as an adhesive. Due to the increased resistance to moisture, its sheets can be used for facade work. In construction, formwork is also made from it for pouring foundations.
- FB - bakelized. It differs from the previous versions by a very high level of moisture resistance. For gluing the veneer, synthetic resin with the addition of bakelite varnish is used. Such material can be safely used in rooms with high humidity levels. In addition, it is able to withstand sudden temperature changes and prolonged exposure to sea or fresh water.
- Laminated. Has on one or both sides a lining layer with a paper-resin coating. Such a coating protects well the inside of the product from mechanical stress. It differs in high wear resistance and moisture resistance.
Note! Film faced plywood does not require moisture protection, as it initially has protective properties!
Using
Plywood is used today for a wide variety of jobs. Depending on the room, one or another group is used. Particular attention should be paid to the humidity of the room. For a bathroom, kitchen and other room with a high level of humidity, you can use the g-type FSF or FB, for other rooms the type of FC is suitable.
Multi-layer plywood for the floor is very popular. It is very important to choose the right thickness so that it can withstand the load from furniture and human walking. The sheets are attached to a pre-prepared wooden frame, which is made of bars. Fastening is carried out using self-tapping screws of suitable length. It is very important that the cap does not protrude above the surface when screwing, otherwise it is possible to damage the floor covering, which will be laid on top. With proper use, such a floor will serve for many years, retaining its positive qualities.
In crosswords, you can also find queries on this topic, for example, 4-letter plywood. In this case, you need to write the word "veneer" into the cells, although this is not the plywood itself, but only its component - one layer.
In general, this is an environmentally friendly material that can be used in any room, even in a children's room. The main thing is to buy it from trusted suppliers who produce it according to all norms and standards.
Today, such a building material as plywood is considered one of the most commonly used in various construction processes. Plywood sheets can be used both for arranging the floor and for cladding the facade of a house, walls of a room, etc. Depending on the area of \u200b\u200bapplication, there are different type of plywood: construction, facing and specialized. There is even such an option as reinforced plywood. Plywood is classified according to various criteria, for example, according to the material from which the product was made, the treatment of its surfaces, and the impregnation used. The choice of such material should be carried out depending on what it is to be used for. So, if plywood is needed to create furniture, you should choose only environmentally friendly materials, without any impregnation.
Types of plywood for finishing
Among the sheets used in construction, five types of plywood are known:
Grade E is the highest quality option. Such plywood has no harmful impurities in its structure, is not deformed and has a smooth surface.
Grade 1 plywood sheet allows for a small amount of inclusions, but the quality is also at the highest level.
Grade 2 is characterized by additional inclusions no more than 2 cm in length, such material is of good quality. This type can be used for cladding.
Grade 3 allows the presence of up to 10 wormholes, their length varies within 0.5 cm.
Grade 4 is the lowest, it is used mainly for technical work. It is characterized by a large number of defects that do not in any way affect the quality of the product, but rather the appearance.
Raw materials for making plywood
Various tree species are used to create a plywood sheet. But the most popular of these are conifers and birch. Birch is used as a raw material in almost all industries. This is due to the fact that it has a beautiful appearance, moreover, it has high strength. Also, birch is characterized by resistance to various influences. The disadvantage of such raw materials is only the high cost, therefore, it is used mainly for the creation and upholstery of furniture and various decorative elements.
Conifers have a lower cost, due to this they are often used in various construction works. Of these, pine, larch, etc. are most often used. The material made from coniferous species is of high quality, decorative appearance and good strength indicators.
Plywood sheets also differ in the number of layers in their structure. Currently, a material consisting of one, two and three layers is used, but it is better if the number of layers is odd. Thus, the inner layers of the product will be perpendicular to the outer layers, and this significantly increases the strength of the coating, makes it resistant to various types of influences and mechanical loads.
Plywood sheet processing
Depending on the processing method and the impregnation used, this building material is divided into the following types:
FSF is a plywood made of phenol-formaldehyde-based resin. Such building material is of high quality, resistant to high humidity, and also has high strength.
Laminated plywood - a special type of board that goes through the lamination process. This provides the product with high moisture resistance and makes it possible to use it in the construction of formwork.
FC is a type based on carbamide glue. This option is used for interior work, namely for wall cladding, flooring.
FB - plywood, the impregnation of which consists of bakelite varnish. This option is resistant to aggressive influences, for example, high humidity.
BS - plywood board, in addition to the bakelite composition, is also impregnated with an alcohol-containing mixture. Plywood of this type is used most often in aircraft construction.
BV is a material impregnated with a bakelite substance and an alcohol-insoluble composition.
Plywood also differs depending on the surface treated. So, if the material has the Ш2 marking, then it is sanded on both sides; if the Ш1 marking is present, the plywood is sanded on only one side. If the product has the NSh marking, its surfaces are not polished at all.
There are different GOSTs depending on the type of top layer processing. When studying them, you can get additional information about the purchased material. So, some materials are developed for general work, made from coniferous trees. Others are made from chipboard material. There is also a type for general use, the outer layer of which is also made from hardwood.
Plywood types by application
A large assortment of such building materials as plywood makes it possible to use it in various fields, not only in construction, but also for finishing the surface of the floor or walls, for designing furniture, in the automotive industry, in the aircraft industry.
At the moment, the following types of plywood boards are produced:
Plywood FSF is a special product that is resistant to moisture;
FK plywood does not have high moisture resistance, it is used in internal works;
FBA plywood has an average water resistance; in this case, albuminocasein adhesive is used as an impregnation.
Regardless of how many layers a plywood sheet has, each veneer layer should be perpendicular to the previous one.
Plywood companies make conventional and wide-format plywood boards, they can be used in construction, namely, for cladding. Depending on the location of the veneer fibers, plywood is divided into longitudinal and transverse variants.
Construction and bakelite plywood
The most popular type is construction plywood sheets, which are made from pine and larch. The thickness of such a plate is 2-4 mm. There are combined options for the production of which two different types of wood are used.
Products based on the use of softwood veneer are divided into 6 types. They are used for both outdoor and indoor construction work.
The combined plywood is presented in a large assortment. In length, such sheets can be almost 2.5 m, while the width can be 1.20 m.The thickness of plywood sheets ranges from 0.8 to 3 cm.
There is also plywood, for the production of which alder is used. Such a representative of coniferous forests is used much less often, but it has a higher quality.
Bakelite plywood consists of birch veneer, phenol-formaldehyde resin is used as an impregnation. The outer layer of such an article can be impregnated with an alcohol-soluble composition. Plywood of this type is characterized by high strength, it can withstand heavy loads, therefore its use is not limited only to internal work, it is used in shipbuilding, construction, aircraft construction, etc. the thickness of such a product is 0.5-1.8 cm, length 7.70-1 , 5 m, width - 1.55-1.2 m.
Plywood for facing has a rotary cut veneer in its structure. In this case, one side or both at once have a polished surface, which makes it possible to use it for finishing work. In this case, the adhesive can be based on phenol formaldehyde or urea formaldehyde. The facing plywood is available in two grades.
Decorative and reinforced plywood
There is also a plywood sheet for decorative work. Such a board has a paper layer in its structure. The plywood sheet can be colorless or painted, it can have a pattern that imitates the surface of natural wood.
Also, the plywood material can be coated with a fire resistant material or plastic compound. Also known is plywood coated with a layer of metal or a layer of polyvinyl chloride.
If reinforcement of plywood is required, the reinforced type is used. Such a plate has a complex composition, the veneer used can be made of rubber, special mesh. Due to this, not only the strength of the coating increases, but also the rigidity increases. In this case, the mass of the plywood sheet practically does not change.
Plywood is a rotary cut veneer, the sheets of which are tightly glued between. The name is taken from the French word for superimpose. Thus, 3-5 layers of veneer in special conditions are superimposed on each other, creating a fairly practical building material, the use of which is also possible in furniture production. It is noteworthy that less depends on the veneer, and more on the glue with which it is glued.
The minimum number of veneered sheets in plywood is 3. The veneer layers are arranged so that in adjacent rows the fibers are perpendicular. This way of placing the glued sawdust guarantees not only a certain form stability, but also the necessary strength.
The latter is also achieved through the use of new technologies, which include:
- lamination;
- veneering with planed material;
- coloring;
- varnishing.
Plywood weighs much less than natural wood. puts it alongside other modern materials. At the same time, it has high heat-conducting qualities. Also, most of its species are certified for environmental safety.
Manufacturers produce several types and types of plywood. And each in its own way has a designation as to where it will be most successful.
A few words about what kind of plywood is:
Plywood division by wood type
In addition to the standard marking, plywood is usually classified according to the following main characteristics:
- Application of the material.
- The degree of plywood water resistance.
- The composition of the veneer, meaning the type of wood.
- Plywood thickness.
- Belonging to a grade that depends on the external processing materials of plywood.
- Sanded or not. The markings include: NSh - not ground, Ш1 - ground one of the sides, Ш2 - ground both sides.
- Sheet sizes.
- Emission class. Its level depends on the presence of formaldehyde resins in the material.
- Sheet construction.
And the main composition of plywood - wood allows it to be divided into the following types:
- birch;
- coniferous;
- combined.
For the manufacture of internal plywood sheets, conifers are most often used, but for external deciduous ones. In this case, the thickness of the veneer used inside does not exceed 4 millimeters. But for outer sheets, it is usually 3.5 millimeters. The very same plywood is at least 3, maximum 30 millimeters. Large format plywood has a side length of 1,830 millimeters.
Birch
Plywood, which contains 90% of birch shavings and sawdust, is called birch. It can be used wherever a durable material containing wood residues is required. Such plywood has high physical and mechanical properties. They are largely due to the multilayer structure.
That is why birch plywood is used:
- in construction;
- automotive industry;
- for internal lining of cars;
- in the manufacture of durable packaging and other containers.
Birch plywood can even be used for interior cladding. Such plywood is based on sawdust and shavings from light birch wood.
Its physical parameters are as follows:
- 650 kg / m3 - material density.
- High tensile strength that is 20% higher than softwood plywood.
- Uniform texture.
- Complete absence of resinousness.
Such qualities give the right to put birch plywood first in the rating of these materials.
Photo of birch plywood
Coniferous
This type of plywood is made from coniferous trees. The properties of wood provide strength, density and some hardness to the plywood produced. At the same time, coniferous plywood is resistant to rotting and the appearance of fungi. This is largely achieved due to the fact that nature itself has impregnated the wood with resins, which make it possible to protect the materials, which include wood derivatives.
Softwood plywood is used in civil engineering. With her help:
- sheathe the walls;
- carry out interior partitions;
- make the base for the roof;
- fence construction sites;
- perform flooring and formwork;
- make pallets, containers, packages.
Photo of coniferous plywood
Combined
The material, which is positioned not only as expensive, but also as strong and absolutely harmless as possible, can only partially consist of valuable wood species. As a rule, veneer sheets made of familiar types of wood are the basis of plywood, but for cladding, more expensive, which means durable and beautiful veneer can be used.
There are three types of veneer:
- sawn,
- planed,
- shelled.
Peeled plywood can give the veneer an interesting, expensive texture. The most expensive type of plywood is. The top covering, which is made in the form of a protective film, allows this type of plywood to be classified as one of the hardest. But, as a rule, the use of plywood in different industries is implied already at the manufacturing stage and the manufacturer indicates why the plywood was made in the marking.
Photo of combined plywood
Separation of plywood according to its purpose
It turned out that the layered construction of plywood can be so diverse that it is possible to use the finished material in various industries.
That is why, according to its operational purpose, plywood is divided into:
- construction;
- general purpose;
- furniture;
- laminated;
- formwork;
- furniture;
- decorative and;
- shipboard;
- aviation.
Many types of plywood are close to each other. The most expensive is plywood, which can be used in aircraft construction.
Aviation
The main difference between such plywood is that the thinnest sheets are used for its manufacture - 0.4 millimeters. Resin SFZh-3011 or bakelite film serve as a binder between the layers (their maximum number is 10).
Only high quality components are selected for aircraft plywood. Thanks to this, as well as the strict implementation of the technology established by GOSTs, it is possible to obtain a material that has maximum strength. And at the same time, aircraft plywood has a minimum weight with a maximum density.
Aviation plywood is widely used in:
- aircraft construction
- aeromodelling;
- instrumentation;
- ship building;
- creation of some musical instruments.
It is impossible to find this material on sale. It is produced in limited quantities, not by every plant, and strictly to order. Aviation plywood is the strongest, strongest and most durable.
Due to the uniqueness of the workmanship and the precise selection of all components, this material can be classified as elite. Assessment of all its technical characteristics, appearance and service life 5.
Photo of aviation plywood
Ship
In order to be part of a floating device, parts of plywood are not only glued together with a special agent, but also pre-impregnated with moisture-resistant agents. Shipborne - Marine plywood can only be made from high strength wood like Acuomea Kleinea. This tree grows in the rainforests of the Congo Basin.
Okume or gabuna veneer can be made only at factories of the European Union, the USA and Israel. The material produced there is called "Luan" or "Moranti". Manufacturers offer varieties of their material, where the difference is in sheet thickness, size and weight.
Ship plywood is more expensive than elite wood, but its high-quality processing, the ability to order a sheet of the desired configuration at the manufacturing stage allows you to set this material to a solid 5+.
Photo of ship plywood
Furniture
For the manufacture of furniture, a material can be used that does not require increased physical and technological properties. As a rule, any plywood can be used for furniture production. But if you still follow the GOSTs, then it is better to give preference to those that are labeled as FC or FSF.
Plywood FC is used for the production of any furniture, as well as as a base for parquet floors. FSF possesses improved properties of moisture resistance, mechanical strength and wear resistance.
This type of plywood is in maximum demand. Any furniture is made from it, including for kitchens and bathrooms. Considering the affordability of the price and the possibility of easy processing, the material deserves a solid 5.
Photo of furniture plywood
Formwork
There can be no real construction without preparatory work. Formwork is needed at many stages of construction. Considering that the beauty of the materials at hand is not needed for the formwork, but only their relative strength, however, any plywood cannot be used here.
It is best to use moisture-resistant laminated plywood of the FBA, FB, FK brands for formwork. Thanks to its use, it is possible to reduce the cost of the construction process, as well as significantly reduce the time spent.
In Soviet times, we did not make film faced plywood. It was brought from Finland, so it is called Finnish. In any case, after being used for formwork, plywood can no longer be used anywhere.
Plain film faced plywood became the ancestor of such important types of this material as construction and transport plywood.
Photo of formwork plywood
Construction
GOST 3916-69 indicates that glued plywood can be used in construction.
For use in preparatory work, plywood of the following markings can be used:
- FBSV.
When using plywood strictly for its intended purpose, you can get high-quality material that can serve for more than one year. Nevertheless, in comparison with some modern types of building materials, plywood is still somewhat inferior to them in terms of durability, ease of processing, appearance and quality.
Photo of construction plywood
Transport
For road and river transport, it is possible to use film faced plywood, which has a mesh layer. It is he who is responsible for the fact that, with its strength and moisture resistance, such plywood has anti-slip properties.
For the convenience of transporting a wide variety of goods in trucks and small boats, plywood of the following thickness can be used:
- 24 and 27 millimeters. The body and doors of the car are trimmed with laminated plywood, and the floor is covered with mesh.
- 15 to 21 millimeters. This plywood is used for semi-trailers and semi-trucks.
- 9.5 and 12 millimeters. Despite its small thickness, such plywood can even be used for the interior arrangement of boats and boats.
- 6.5 mm. Such plywood can be used for interior wall cladding of vans and industrial refrigerators.
Transport plywood is not used in everyday life, its use in cars and the opportunities that it gives them offset the high cost. Such material deserves a grade 5.
Photo of transport plywood
Decorative
The fact that manufacturers make plywood strong and beautiful allows it to be used for facing work.
Interior plywood has many positive characteristics:
- it looks great, it imitates natural wood well;
- has high soundproofing characteristics;
- has good thermal conductivity;
- easy and quick to assemble;
- is relatively inexpensive.
Photo of decorative plywood
Advantages and disadvantages of plywood
This material is in no way capable of replacing natural wood.
However, it has advantages that can put it even higher than the tree:
- Cost. The price of plywood is several times cheaper than wood.
- Ease. The material weighs much less than wood.
- Ease of installation. You don't need expensive tools to create any building structures.
- High parameters of sound insulation and thermal conductivity. These figures are significantly higher than that of natural wood.
- Resistant to fungi, mold and other microorganisms.
Under the right operating conditions, plywood can serve as a facing material for more than a decade. It is widely used in concert halls, sports halls, hospitals, offices, and less often in apartments.
At the same time, plywood has a number of significant disadvantages. Among them are:
- Poor performance in relation to wood.
- Fear of moisture.
- If any of the sides of the plywood is damaged, it may "spill".
In general, it should be borne in mind that plywood is one of the types of construction and furniture material produced from wood waste. That is why it is not worth expecting that the purchase of plywood will allow you to have a universal material with which you can create a modern, durable, beautiful structure that is not inferior in quality to the Lebanese cedar. If you use plywood according to the manufacturer's recommendations, you can successfully make from this material what it is intended for.
Plywood - artificial sheet building material. A plywood sheet is made by tightly gluing and pressing an odd number of thin layers of wood (veneer) in such a way that the fibers of adjacent veneer layers are mutually perpendicular, while observing the following rule - a plywood sheet should be symmetrical with respect to the middle (central) veneer layer. Thanks to this, the plywood sheet has excellent characteristics in terms of strength, durability, resistance to stress, impact resistance and moisture resistance.
By brands plywood is mainly divided into four types: FC, FSF, FB, FOF.
"FK" and "FSF", "FB" or "FOF", which make up the marking, denote resistance to moisture, which is determined by the type of glue and coating of the top veneer of the plywood sheet. Plywood is glued with synthetic thermosetting adhesives: phenol-formaldehyde and urea.
- Plywood FK - medium water resistance or moisture resistant. Bonded with adhesives based on carbamide resins. Recommended for indoor use, as a rule.
- Plywood FSF - increased water resistance. It is glued with adhesives based on phenol-formaldehyde resins. Recommended for use both indoors and (mainly) for outdoor use.
- Plywood FB - bakelized plywood. Each veneer layer of such plywood is impregnated with bakelite varnish, and then glued together with glue based on phenol-formaldehyde resins. Recommended for use in aggressive environments, tropical climates, aquatic environments. Scope - self-summer - shipbuilding.
- FOF plywood (film faced plywood) - FSF birch plywood faced with a film coating (high density paper impregnated with synthetic resin) on one or both sides. Recommended for outdoor use. Scope (mainly) - monolithic construction, formwork structures.
By type of woodfrom which it is made. Depending on the type of wood used for the manufacture of plywood, such main types of plywood will be divided as birch (made from hardwood veneer), coniferous (made from softwood veneer) and combined. As a rule, plywood is considered to be made from the type of wood from which its outer layers are made.
By surface type depending on the appearance of the outer layers, the following main varieties are distinguished: grade I (or 1), grade II (or 2), grade III (or 3), grade IV (or 4), grade V (or 5). The grade designation consists of two numbers - two sides of the sheet and is written through a slash (fraction) as follows: 2/3, 4/4, etc. or II / III, IV / IV, etc.
In some cases (European designations), plywood grades can be designated by letters: E (elite), A, B +, B, S, Bs, BBx, BBxs, BB, CP, CPs, C, WG.
Determinant of grade - the number of knots per 1 sq. m of the surface of the outer sheet.
Plywood of the first grade - plywood which has practically no external defects. Only a few healthy intergrown knots up to 8 mm in diameter and slight brown streaks are allowed.
Plywood of the second grade - plywood that allows small restoration of the surface of the sheet using veneer inserts and sealing of knots and open defects.
Plywood of the third grade differs from the first and second in that such plywood is used for the manufacture of structures that are hidden from visual review. It is used for various special containers and packaging. By and large, the third grade is what is rejected from the second.
Plywood of the fourth grade - plywood admitting all manufacturing defects. This concerns, first of all, knots, of which there can be an unlimited number. The main thing is that the manufacturer guarantees good gluing of the sheets. Plywood of the fourth grade is used in the manufacture of containers and packaging.
Types of plywood
By the degree of mechanical surface treatment plywood of the following types is distinguished:- NSh - unpolished;
- W (W 1) - sanded on one side;
- W (W 2) - sanded on both sides.
A letter indicating the degree of machining is added to the designation of the grade and grade of plywood.
For all types of sanded plywood, it is mandatory to indicate the emission class of free formaldehyde E1 and E2. The quality of sanded plywood is assessed by many indicators, for example: ultimate shear strength, static bending, tensile strength of samples, as well as the following indicators - moisture content, presence of defects. The thickness of the sheets (plates) of sanded plywood is produced from 4 to 40 mm. Plywood is sanded to create a smooth plywood surface and equalize in thickness, remove dirt and scratches.
plywood Е1 - formaldehyde content per 100 g of absolutely dry mass of plywood not more than 10 mg inclusive
plywood Е2 - formaldehyde content per 100 g of absolutely dry mass of plywood from 10 mg to 30 mg inclusive
The main factors in the overall assessment of the quality of plywood sheet - ultimate shear strength, static bending, tensile strength of samples. Important properties are moisture content, structure, color of knots, presence of defects.
Plywood is a versatile material that is used almost universally for a variety of purposes. Externally, plywood looks like rectangular sheets of certain sizes of various thicknesses, consisting of many layers (at least 3) of wood fiber raw materials. Plywood can be produced from wood veneer or wood veneer.
Most often, plywood is made from veneer, the layers of which are laid perpendicular to each other and glued with special compounds. This manufacturing technology provides excellent strength and wear resistance, and also increases the material's ability to resist moisture penetration.
Varieties of plywood
Many types of plywood are produced, it can be moisture resistant, laminated, made of different varieties and types of wood, as well as have different thicknesses and purposes. How is the type of plywood determined by material? In this case, attention is paid only to the outer layer of plywood, not taking into account the inner ones.
Depending on the type of raw material, the following types of plywood are distinguished:
- birch;
- coniferous;
- combined.
Birch plywood made from hardwood veneer (birch). Such veneer has a uniform, more homogeneous structure, has a good density (about 650 kg / m3). Birch veneer plywood is much stronger than its counterparts made from other materials. The difference in strength sometimes reaches 20%.
However, the cost of birch plywood is slightly higher than that of analogues. This is due to the absence of natural resins in birch veneer, which means that additional compounds are required to create good quality plywood. Birch plywood has become quite widespread. It is used in the construction of private houses, for the packaging of transported goods, ship and car building, as well as in many areas of the automotive industry.
Coniferous plywood cheaper than birch. In Russia, coniferous plywood is usually made from pine and spruce bark. Such plywood is lighter, has an interesting appearance due to the wood pattern. However, softwood plywood is less durable than birch plywood. Coniferous veneer contains natural resin, which contributes to a longer life of the material.
Natural resins protect plywood from moisture and decay. Softwood plywood has received the greatest demand in individual housing construction, as well as in the field of interior design and the creation of decorative elements.
The next type of plywood is combined ... This material consists of both birch and coniferous wood fibers. It combines the advantages of birch and softwood plywood. Combined plywood resembles birch in strength and technical characteristics, however, its price is somewhat lower. Composite plywood is widely used in construction, furniture production and packaging.
Types of plywood by adhesive
The next aspect, according to which the separation of plywood occurs, is the type used for gluing a layer of the composition.
Depending on the adhesive, plywood can be:
FBA. This plywood is produced using albuminocasein glue. FBA plywood is an environmentally friendly material and is not waterproof. Such plywood can be used for any purpose at low humidity.
FC. Plywood type FK is produced with urea adhesive. Plywood has a low moisture resistance. The raw materials of FC plywood do not emit harmful substances, the material is absolutely environmentally friendly, so it can be used for interior work in residential premises and childcare facilities.
FKM. Melamine glue is used in the production process of this type of plywood. Plywood has average moisture resistance. The adhesive contains a small amount of harmful substances. FKM plywood can be used in conditions of low humidity levels and where there are no strict restrictions on the toxicity of materials.
FSF. Plywood of the FSF type has excellent moisture resistance. However, in its production, a phenol-formaldehyde adhesive is used, which has a fairly large amount of harmful substances. The use of FSF plywood in residential premises, as well as for the production of furniture, is highly discouraged due to the high risk of harm to human health.
FB. This type of plywood is obtained by impregnating veneer sheets with bakelite glue. FB plywood has excellent moisture resistance and is also capable of "working" under the influence of aggressive media. Such plywood can be used in difficult climatic conditions (at low or high temperatures), it perfectly withstands the effects of sea water, various microorganisms, acids and alkalis. In turn, bakelite plywood is subdivided depending on the composition of resins (FBS, FBV) and the type of gluing.
Bakelite plywood FBS is impregnated with alcohol-soluble adhesives, has high moisture resistance and is of the following types:
- bakelite plywood FBS - the highest quality class of this material due to the impregnation of all layers with bakelite alcohol-soluble glue;
- plywood FBS1 has a slightly worse quality. The technology for the production of this plywood provides for smearing, not impregnation, of veneer layers;
- class FBS1A has the lowest quality among bakelite plywood based on alcohol-soluble adhesives. Here, only longitudinally located veneer layers are coated with an adhesive.
The next subspecies of bakelite plywood is FBV , made on water-soluble adhesives. Plywood FBV is of two types: FBV (where the inner layers of veneer are coated with, and the outer ones are impregnated with adhesives) and FBV1 (where all layers of veneer are only coated with adhesives). The main advantage of such plywood is its excellent strength characteristics.
Types of plywood by processing method
The next criterion for grouping plywood is the method of surface treatment.
According to the surface texture, plywood is:
- Laminated. For this, plywood is covered with special waterproof films. Film faced plywood is widely used for decoration and paneling of vans.
- Sanded on one side.
- Sanded on both sides.
- Unpolished.
On the website portal, you can buy any kind of plywood, as well as see photos of samples and compare prices of suppliers.
Plywood classification by purpose
The area of \u200b\u200bapplication of plywood (laminated, sanded, moisture resistant and other types) is not limited to construction, due to its properties the material is extremely in demand in various fields.
The portal site offers the following classification of plywood by purpose:
Ship. Only the highest quality types and grades of moisture-resistant plywood FB (on bakelite glue) are used for finishing shipping facilities, which work perfectly in conditions of high humidity and aggressive environments.
Furniture. The types of plywood used for furniture must be environmentally friendly, wear-resistant and durable. As a rule, combined FC plywood is used for furniture.
Construction. In the construction industry, as a rule, grades 3/4 and 4/4 of birch plywood are used. These types of plywood can be used for floors, walls and other structures as a rough finish.
Aviation. For these purposes, FSF plywood grades are used. This plywood has excellent technical characteristics and is ideal for such challenging and demanding industries as aircraft, shipping, railroad cars and automobiles.
Formwork. To create the formwork, FB film faced plywood is used, which has excellent characteristics in terms of moisture and wear resistance, strength and exposure to an aggressive environment.
Decorative. FK plywood is used for finishing the premises. This type of plywood must have excellent outer layer characteristics (even surface with a textured pattern). Plywood of this type, as a rule, is made from valuable wood species, or from wood of the highest grade.
Automotive. For cars, as a rule, plywood of the FSF type is used with a laminated or mesh-ribbed surface. Plywood has high strength, moisture resistance and durability. It is used for covering all elements of a truck body (walls, floor, doors, ceiling).
Plywood: assortment, characteristics
Currently, plywood is produced in five grades. The technical characteristics of each grade of plywood are strictly defined in the current GOST.
Plywood grades:
Grade 4. This grade of plywood is the cheapest and lowest quality. Plywood sheets of grade 4 may have multiple wormholes, defects in uniformity (knotted knots) and uneven edges of the sheet (depressions up to 0.5 mm). This type of plywood is used for interior rough finishing. The most common area of \u200b\u200bapplication for this type of plywood is the production of various packaging and taring.
Grade 3. Plywood of grade 3 can also have wormholes, but in a strictly limited quantity (no more than 10 pcs / sq. M.). The size of the wormholes is also limited (the diameter should not exceed 6 mm), and the number of all defects on the plywood sheet should be less than 9. Grade 3 plywood is also used for rough finishing of premises. However, it is allowed to use this type of plywood in finishing works, provided that the surface of the sheets of paint and varnish compositions is applied to hide material defects.
Grade 2. Plywood can have the following defects: cracks no more than 20 cm, areas with leaked glue (if the area of \u200b\u200bthe site is up to 2% of the total square of the sheet), wood inserts. This plywood, like grade 3, is used for rough and fine finishing for painting.
Grade 1. Defects allowed on grade 1 plywood are cracks and warpage less than 2 cm long. Grade 1 plywood in construction is used for finishing inside and out.
Variety E. Plywood E belongs to the elite grade. Plywood of grade E must clearly comply with the characteristics declared in GOST, namely: it must not have wormholes, cracks and other defects, except for accidental deformations in the structure of the wood itself. The elite grade plywood is the highest quality and most expensive. It is used for fine finishing.
The construction portal site will help you profitably of various varieties with delivery to the site.