If there is a need to manufacture a curved wooden element, then at first glance it may seem that it is easier to cut out the desired element in a curved form, but in this case the fibers wood material will be cut, thus weakening the strength of the part, and as a result, the entire product. In addition, when sawing, a large waste of material is obtained, which cannot be said about the method when the wooden blank is simply bent.
Wood is cellulose fibers bound together by a chemical called lignin. The flexibility of the tree depends on the arrangement of the fibers.
Pay attention! Only well-dried wood will be a reliable and durable source material for production. various products. However, the change in shape is dry wooden blank the process is complex, because dry wood can break, which is very undesirable.

Having studied the technology of how to bend wood, as well as the basic physical properties wood, which allow you to change its shape and subsequently preserve it, it is quite possible to take up bending wood at home.
Some features of working with wood
Bending of wood is accompanied by its deformation, as well as compression of the inner layers and stretching of the outer ones. It happens that tensile forces lead to rupture of the outer fibers. This can be prevented by carrying out preliminary hydrothermal treatment.
So, you can bend blanks of timber made from solid and laminated wood. In addition, planed and peeled veneer is used for bending. The most flexible are hardwoods. These include beech, ash, birch, hornbeam, maple, oak, poplar, linden and alder. Bent glued blanks are best made from birch veneer. It is worth noting that in the total volume of bent-glued blanks, birch veneer occupies approximately 60%.
When steaming the workpiece, the compressibility increases significantly, namely by a third, while the tensile ability increases by only a few percent. This means that it is not a priori worth thinking about whether it is possible to bend wood thicker than 2 cm.

Steam box heating

First you need to prepare the steam box. It can be made by yourself. Her main task- hold the tree that needs to be bent. There should be a hole in it to allow the steam pressure to escape. Otherwise it will explode.
The steam outlet should be located in the bottom of the box. In addition, the box must contain removable cover, through which it will be possible to pull out the bent tree after it has acquired the desired shape. To hold the bent wood piece in the desired shape, clamps should be used. You can make them yourself from wood or buy them at a specialty store.

Round cuttings should be made from wood - several pieces. Off-center holes are drilled in them. After this, you need to push the bolts through them, and then drill another hole through the sides to push them in tightly. Such simple crafts can become excellent clips.
Now it’s time to steam the wood; to do this, you should take care of the heat source and close the wood piece in the steam box. For every 2.5 cm of thickness of the workpiece, the product needs to be steamed for about an hour. After time has passed, the tree must be removed from the box and given the required shape. The process must be completed very quickly. The workpiece bends neatly and softly.
Pay attention! Some types of wood bend more easily than others due to different elasticity. Different ways require force different sizes.
Once the desired result is achieved, the bent tree must be fixed in this position. You can secure the tree while shaping it. This makes it easier to control the process.

Using chemical impregnation

To destroy lignin bonds between fibers, you can act on wood chemicals, and it is quite possible to do this at home. Ammonia is ideal for this. The workpiece is soaked in 25% aqueous solution ammonia. After which it becomes very obedient and elastic, which allows you to bend, twist it and squeeze out relief shapes in it under pressure.
Pay attention! Ammonia is dangerous! Therefore, when working with it, you should follow all safety rules. Soaking the workpiece should be carried out in a tightly closed container located in a well-ventilated room.
Ammonia aqueous solutionAmmonia aqueous solution
How longer wood is in an ammonia solution, the more plastic it becomes. After soaking the workpiece and giving it a shape, you need to leave it in this curved form. This is necessary to fix the shape, and also for the ammonia to evaporate. Again, bent wood should be left in a ventilated area. Interestingly, after the ammonia evaporates, the wood fibers will regain their former strength, and this will allow the workpiece to retain its shape!

First you need to make a piece of wood that will be bent. The boards should be slightly longer than the length of the finished part. This is because bending will shorten the slats. Before you start cutting, you should draw a diagonal line with a pencil. This needs to be done across the underside of the board. This will maintain the sequence of the slats after they have been moved.
The boards are cut with a straight-layer edge, in no case front side. So, they can be added together with the least change. A layer of cork is applied to the mold. This will help avoid any unevenness in the shape of the saw, allowing for a cleaner bend. In addition, the cork will keep the delamination in shape. Now glue is applied to the top side of one of the wooden slats.
The glue is applied to the lamellas with a roller. It is best to use urea-formaldehyde glue, consisting of 2 parts. It has a high level of adhesion but takes a long time to dry. Can also be used epoxy resin, but such a composition is very expensive, and not everyone can afford it. Standard wood glue cannot be used in this case. It dries quickly, but is very soft, which is not welcome in this situation.
Boards are held together after gluing. Boards are held together after gluing.
Blank from bent wood should be placed in the mold as quickly as possible. So, another lamella is placed on top of the glue-coated lamella. The process is repeated until the bent piece reaches the desired thickness. The boards are fastened together. After the glue has completely dried, you should shorten it to the desired length.

I drank it as a method
The prepared piece of wood needs to be sawn through. The cuts are made 2/3 of the thickness of the workpiece. They must be with inside bending You should be extremely careful, because rough cuts can break the tree.
Pay attention! The key to success when cutting kerfs is to keep the spacing between cuts as even as possible. Ideally 1.25 cm.
Defects can be hidden with veneerDefects can be hidden with veneer
The cuts are made across the grain of the wood. Next, you should squeeze the edges of the workpiece so as to connect the resulting gaps together. This is the shape the bend will take upon completion of the work. Then the bend is corrected. More often outside treated with veneer, in some cases laminate. This action allows you to correct the bend and hide any defects made during the manufacturing process. Spaces between bent tree hidden simply - to do this, glue and sawdust are mixed, and then the gaps are filled with this mixture.
The cuts are made across the grain of the wood. The cuts are made across the wood grain.
Regardless of the bending method, once the wood is removed from the mold, the bend will relax slightly. In view of this, it needs to be made a little more in order to subsequently compensate for this effect. The sawing method can be used when bending part of the box or metal corner.
So, using these simple recommendations You can bend a tree with your own hands without much effort.

When making furniture, you cannot do without curved parts. You can get them in two ways - sawing and bending. Technologically, it would seem easier to cut out a curved part than to steam, bend and then hold it for a certain time until full readiness. But sawing has a number of negative consequences.

First, there is a high probability of cutting fibers when working with a circular saw (this is what is used with this technology). The consequence of cutting the fibers will be a loss of strength of the part, and, as a consequence, of the entire product as a whole. Secondly, sawing technology requires more material consumption than bending technology. This is obvious and no comment is required. Third - everything curved surfaces sawn parts have end and half-end cut surfaces. This significantly affects the conditions for their further processing and finishing.

Bending allows you to avoid all these disadvantages. Of course, bending requires the presence of special equipment and devices, and this is not always possible. However, bending is also possible in a home workshop. So, what is the technology of the bending process?

Process The production of bent parts includes hydrothermal treatment, bending of blanks and their drying after bending.

Hydrothermal treatment improves the plastic properties of wood. Plasticity is understood as the ability of a material to change its shape without destruction under the influence of external forces and to retain it after the action of the forces is eliminated. Wood acquires its best plastic properties at a humidity of 25 - 30% and a temperature in the center of the workpiece at the time of bending of approximately 100°C.

Hydrothermal treatment of wood is carried out by steaming in boilers with saturated low-pressure steam of 0.02 - 0.05 MPa at a temperature of 102 - 105 ° C.

Since the duration of steaming is determined by the time it takes to reach a given temperature in the center of the steamed workpiece, the steaming time increases with increasing thickness of the workpiece. For example, to steam a workpiece (with an initial humidity of 30% and an initial temperature of 25 ° C) with a thickness of 25 mm to achieve a temperature in the center of the workpiece of 100 ° C, 1 hour is required, with a thickness of 35 mm - 1 hour 50 minutes.

When bending, the workpiece is placed on a tire with stops (Fig. 1), then in a mechanical or hydraulic press the workpiece together with the tire is bent to a given contour; in presses, as a rule, several workpieces are bent simultaneously. At the end of bending, the ends of the tires are tightened with a tie. The bent workpieces are sent for drying along with the tires.

The workpieces are dried for 6 - 8 hours. During drying, the shape of the workpieces is stabilized. After drying, the workpieces are freed from templates and tires and kept for at least 24 hours. After holding, the deviation of the dimensions of the bent workpieces from the original ones is usually ±3 mm. Next, the workpieces are processed.

For bent blanks, peeled veneer, urea-formaldehyde resins KF-BZh, KF-Zh, KF-MG, M-70, and particle boards P-1 and P-2 are used. The thickness of the workpiece can be from 4 to 30 mm. Blanks can have a wide variety of profiles: corner, arc-shaped, spherical, U-shaped, trapezoidal and trough-shaped (see Fig. 2). Such blanks are obtained by simultaneously bending and gluing together veneer sheets coated with glue, which are formed into packages (Fig. 3). This technology makes it possible to obtain products of a wide variety architectural forms. In addition, the production of bent-laminated veneer parts is economically feasible due to the low consumption of timber and relatively low labor costs.

Layers of plots are smeared with glue, placed in a template and pressed into place (Fig. 4). After exposure under the press until the glue has completely set, the assembly retains its given shape. Bent-glued units are made from veneer, hardwood and coniferous species, made of plywood. In bent-laminated veneer elements, the direction of the fibers in the veneer layers can be either mutually perpendicular or identical. Bending of veneer, in which the wood fibers remain straight, is called bending across the grain, and in which the fibers bend, bending along the grain.

When designing bent-laminated veneer units that bear significant loads during operation (chair legs, cabinet products), the most rational designs are those with bending along the fibers in all layers. The rigidity of such knots is much higher than knots with mutually perpendicular directions of wood fibers. With the mutually perpendicular direction of the veneer fibers in the layers, bent-glued units up to 10 mm thick are constructed, which do not bear large loads during operation (box walls, etc.). In this case, they are less susceptible to change in shape. The outer layer of such units must have a lobar direction of the fibers (bending along the fibers), since when bending across the fibers, small lobar cracks appear at the bending points, which exclude good finish products.

Acceptable (radii of curvature of bent-laminated veneer elements depend on the following design parameters: veneer thickness, number of veneer layers in the package, package design, bending angle of the workpiece, mold design.

When manufacturing bent-profile units with longitudinal cuts, it is necessary to take into account the dependence of the thickness of the bent elements on the type of wood and the thickness of the bent part.

In the tables, the elements remaining after the cuts are called extreme, the rest - intermediate. The minimum distance between cuts that can be obtained is about 1.5 mm.

As the bending radius of the slab increases, the distance between the cuts decreases (Fig. 5). The width of the cut depends on the bending radius of the slab and the number of cuts. To obtain rounded nodes, a groove is selected in the slab after veneering and sanding in the place where the bend will be. The groove can be rectangular or " dovetail" The thickness of the remaining plywood jumper (bottom of the groove) should be equal to the thickness of the facing plywood with an allowance of 1-1.5 mm. A rounded block of glue is inserted into the rectangular groove, and a strip of veneer is inserted into the dovetail groove. Then the plate is bent and held in the template until the glue sets. To give the corner greater strength, you can place a wooden square on the inside.

If there is a need to create a curved wooden element, then most likely you will encounter a number of difficulties. It may seem easier to cut the required component in a curved form, but in this case the wood fibers will be cut and weaken the strength of the part. In addition, the execution results in a fairly large waste of material.

Stages of performing work on bending boards at home:

	Preparation. Selecting a suitable type of wood and becoming familiar with the general principles of working with it.
	Wood bending options. Heating in a steam box, chemical impregnation, delamination, cutting.

Wood is cellulose fibers bound together by lignin. The straight arrangement of the fibers affects the flexibility of the wood material.

Advice: reliable and durable wood material for creating various products can only be obtained if the wood is well dried. However, a change in the shape of a dry wooden blank is quite complex process, since dry wood can break easily.

Having studied the technology of bending wood, including its main physical properties of wood, which allow you to change its shape, it is quite possible to perform bending wooden material at home.

Features of working with wood

Bending of a wooden material is accompanied by its deformation, stretching outer layers and compression of internal ones. It happens that the tensile force leads to rupture of the outer fibers. This can be prevented by pre-hydrothermal treatment.

You can bend blanks of timber made of laminated wood and solid wood. In addition, peeled and sliced ​​veneer is used to give the required shape. The most plastic is hardwood. Which includes beech, birch, hornbeam, ash, maple, oak, linden, poplar and alder. Glued bent blanks are best made from birch veneer. It should be noted that in the total volume of such blanks, about 60% falls on birch veneer.

According to manufacturing technology bent wood, when steaming a workpiece, its ability to compress significantly increases, namely by a third, while the ability to stretch increases by only a few percent. Therefore, you cannot even think about bending wood thicker than 2 cm.

How to bend a board at home: heating in a steam box

First you need to prepare a steam box, which can be done by yourself. Its main task is to hold the tree that needs to be bent. It must have a hole for steam to escape. Otherwise, an explosion may occur under pressure.

This hole should be in the bottom of the box. In addition, the box must have a removable lid through which the bent wood can be removed after it has received the desired shape. In order to hold the bent wood workpiece in the required shape, it is necessary to use special clamps. You can make them yourself from wood or purchase them at a hardware store.

Several round scraps are made from wood. Holes are drilled in them, offset from the center. After that, you should push the bolts through them, and then drill another one through the sides in order to push them in tightly. Such simple crafts can perfectly serve as clamps.

Now you can start steaming the wood. To do this, you need to close the wooden piece in a steam box and take care of the heat source. For every 2.5 cm of product thickness, the time spent on steaming is about an hour. After its expiration, the tree should be removed from the box and given the required shape by bending it. The process should be carried out very quickly, and the bending itself should be gentle and careful.

Tip: due to different degrees of elasticity, some types of wood will bend more easily than others. Different methods require different amounts of force to be applied.

As soon as the desired result is achieved, the bent workpiece must be fixed in this position. Fastening the tree is possible during the process of forming it new form, making it much easier to control the process.

How to bend a board at home using chemical impregnation

Since lignin is responsible for the durability of wood, its bonds with the fibers must be broken. This can be achieved chemically, and it is quite possible to do this at home. Ammonia is best suited for such purposes. The workpiece is soaked in a 25% aqueous solution of ammonia, which significantly increases its elasticity. This will make it possible to bend, twist it, or squeeze out any relief shapes under pressure.

Tip: Please note that ammonia is dangerous! Therefore, when working with it, you must strictly adhere to all safety regulations. Soaking of wood should be carried out in a tightly closed container, which is located in a well-ventilated area.

The longer the wood is soaked in an ammonia solution, the more plastic it will become later. After soaking the workpiece and forming its new shape, you should leave it in a similar curved form. This is necessary not only to fix the shape, but also to evaporate ammonia. However, bent wood should be left in a ventilated area. Interestingly, when the ammonia evaporates, the wood fibers will regain the same strength as before, allowing the workpiece to retain its shape!

How to bend a board at home: layering method

First, it is necessary to harvest wood, which will subsequently be subject to bending. It is extremely important that the boards are slightly longer than the length of the required part. This is explained by the fact that the bending tames the lamellas. Before you start cutting, you will need to draw a diagonal straight line with a pencil. This must be done across the bottom side of the workpiece, which will make it possible to maintain their sequence after moving the lamellas.

The boards must be cut with a straight-layer edge, and not with the right side. This way they can be put together with the least amount of change. A layer of cork is applied to the mold, which will help avoid any unevenness in the shape of the saw and will make it possible to make a more even bend. In addition, the cork will keep the delamination in shape. After this, glue is applied to the upper side of one of the lamellas with a roller.

It is best to use urea-formaldehyde glue, consisting of two parts. He has high level clutch, but takes a long time to dry.

You can also use epoxy resin, but such a composition will be very expensive, and not everyone can afford it. Standard option Wood glue will not work in this case. Although it dries quickly, it is very soft, which in this case is not welcome.

The bentwood product must be placed into the mold as soon as possible. So, another one is placed on the lamella coated with glue. The process must be repeated until the bent workpiece reaches the desired thickness. The boards are fastened together. After the glue has completely dried, you should shorten it to the required length.

How to bend a board at home: cut

The prepared piece of wood must be sawn through. The cuts are calculated at 2/3 of the thickness of the workpiece. They should be located on the inside of the bend. You need to be extremely careful, as rough cuts can not only deform the tree, but even break it completely.

Tip: The key to success when cutting is to keep the distance between cuts as even as possible. Ideal option 1.25 cm.

The cuts are made across the grain of the wood. Then you need to compress the edges of the workpiece, which will allow you to connect the resulting gaps into one whole. This is the shape it gets bent at the end of the work. After that it is corrected.

In most cases, the outer side is treated with veneer, less often with laminate. This action makes it possible to correct the bend and hide almost any defects made during the manufacturing process. Gaps in bent wood are hidden very simply - for this, sawdust and glue are mixed, after which the gaps are filled with the mixture.

Regardless of the bend option, after the workpiece is removed from the mold, the bend will relax a little. In view of this, it should be made a little larger in order to subsequently compensate for this effect. The sawing method is used when bending a metal corner or part of a box.

So, using these recommendations, you can bend a tree with your own hands without any problems.

In the woodworking industry, curved parts are produced in large quantities. The manufacture of curved parts is carried out in two ways: cutting from boards or slabs And bending straight bars (solid bent parts) or layers of wood with simultaneous gluing (bent-glued parts).

Technological process of bending wood. The technological process of bending solid wood bars includes the following operations: procurement of material for bending, hydrothermal treatment, bending and drying.

Preparation of material for bending. Blanks for bending are obtained from unedged boards by cutting them on circular saws. The following requirements apply to blanks for bending.

The cross-layer should not exceed 10°. With conventional bending methods, knots are absolutely not allowed in the workpieces. In workpieces with simultaneous pressing, knots are allowed within large limits, which sharply increases the yield of workpieces. Workpieces should be cut out taking into account allowances for subsequent processing of parts. When bending with simultaneous pressing, in addition to the processing allowance, an allowance must be provided for pressing the wood across the fibers and an increased allowance along the length of the workpiece. In order to increase the yield of blanks for bending, it is recommended to cut the boards after preliminary marking.

In small enterprises, the method of obtaining blanks for bending by splitting blocks has been preserved. The split billet does not have a cross-layer, therefore, when bent, it produces a lower percentage of rejects. However, this method is very labor-intensive, since it is done manually and gives a 20-25% lower yield of blanks from the ridge than when sawing it.

After cutting (or splitting), blanks for parts with a round cross-section are processed on lathe-copying or round-blade machines, and blanks for parts rectangular section- on longitudinal milling machines. You can also bend unplaned workpieces, but in this case the boards are cut with planing saws, which give a clean and accurate cut.

Hydrothermal treatment. Hydrothermal treatment of wood before bending is carried out in order to increase the plasticity of wood. Optimal plasticity of wood is achieved when it is heated while wet. This is explained by the fact that when heated, some of the substances that make up the cells transform into a colloidal state.

As a result, the ability of cells and the entire wood to deform increases. When drying deformed (bent) wood, colloidal substances harden and retain the shape given to the workpiece.

Hydrothermal treatment of wood before bending is carried out by boiling in hot water or steaming. For boiling, wooden vats or metal baths and tanks are used. The water in baths and vats is heated by steam.

The water temperature is maintained at 90-95°C, without bringing it to a boil. The duration of boiling depends on the initial humidity, size and type of wood.

When boiling, it is difficult to obtain a uniform temperature and humidity throughout the entire workpiece; the outer layers become oversaturated with water. Therefore, boiling in hot water is used only in cases where steaming is technically difficult.

Most wide application In production, wood was steamed in an atmosphere of saturated steam. Steaming allows you to heat the wood to the desired temperature (70-80°C), regulate the moisture content of the wood and always obtain it close to optimal for bending, i.e. about 25-30%.

For steaming, saturated low pressure steam (0.02-0.05 MPa) is used, which corresponds to a temperature of 102-105 ° C. Steaming of wood is carried out in hermetically sealed metal drum boilers or concrete chambers. The capacity of the boilers and chambers is small, designed for laying bars in the amount of 30-40 pieces.

The boilers are located at each bending machine and are connected to each other by a steam line into a battery. The bars in boilers and chambers are placed on gaskets to ensure better washing with steam.

The duration of steaming depends on the initial humidity and temperature of the wood, the size of the bars and the steam pressure in the boiler. The steaming time is determined according to a special diagram. For example, for workpieces with a thickness of 40 mm at an initial humidity of 30% and a steam pressure in the steaming boiler of 0.03-0.05 MPa, the steaming duration is 12-13 minutes, and for workpieces with a thickness of 80 mm - 65 minutes.

Plywood, when bent to small radii of curvature, can also be subjected to hydrothermal treatment. Plywood glued synthetic adhesives, boil, and glued with casein or albumin glue, only steam it.

The workpieces removed from the steaming boiler or cooking tank must be bent immediately. The outer layers of wood, which experience the greatest stress when bending, should not be allowed to cool.

Wood bending and equipment. Wood bending machines are divided into two types: cold And hot forms.

Machines of the first type (Fig. 4.13) are used for bending on a closed loop. The bars bend around a removable, unheated rotating template 6. Template with tire 2 is put on the vertical shaft 8 , which is given in rotational movement from the electric motor through the gearbox 7.

The free end of the tire is fixed in the carriage 4, sliding along guides 3. Bar 5 is placed between the template 6 and tire 2 and is secured with a movable stop. Then the electric motor turns on, and the shaft rotates 8 with a template placed on it and the block bends along with the tire.

At the bend there is a roller / that tightly presses the block to the template. The rear end of the tire is secured with a bracket to the template. The template with the bar and the tire are removed from the machine and sent to drying, and a new template is put on the machine, and the operation is repeated.

Rice. 4.13.

7 - pressure roller; 2 - tire; 3 - guide; 4 - block; 5 - workpiece;

b - template; 7 - gearbox; 8 - shaft

Rice. 4.14.

7 - hook; 2 - template; 3 - emphasis; 4 - tire; 5 - blank

Bending machines with hot forms are called bending-drying machines; they can be with two-sided or one-sided heating. Machines with double-sided heating are a hydraulic or pneumatic press with heated profile template plates, between which bent bars are clamped. In these machines, the bars are kept in a clamped state until the shape is completely fixed and the workpieces are dried.

In machines with one-sided heating (Fig. 4.14), workpieces 5 are placed between a hot template 2, heated steam, and tire 4 and are secured with a stop 3. The curved blanks 5 together with the tires are secured to the template with special hooks /. The workpieces remain in the machine until the shape given to them is fixed.

This is achieved by drying the wood to approximately 15% humidity, which takes 90-180 minutes. To increase the productivity of bending-drying machines, before bending it is recommended to dry the workpieces to 20% humidity, keep them in the machine until the humidity is 12-15%, and the final drying of the workpieces removed from the machine to production humidity is carried out in drying chambers Oh.

Bending of plywood is carried out in templates consisting of two parts: a matrix and a punch, between which the plywood is laid and bent. In this case, they are used special devices, screws, pneumatic and hydraulic presses.

Bending with simultaneous pressing consists in the fact that the wood is bent around a template equipped with a notch, and in the process of bending from the outside of the workpiece, it is pressed against the template through a tire with a pressing roller.

The workpiece is rolled. The thickness of the workpiece decreases, the layers of wood on the concave side of the workpiece take on a wave-like shape due to the pressing of the template notch, and the outer layers are compacted. This helps to increase the compressive resistance of the concave layers in the wood and the tensile strength of the outer ones.

Bending with simultaneous pressing significantly improves the bending ability of wood and allows you to bend wood with large knots located on the outside of the workpiece. It is used for bending coniferous and soft hardwood wood.

Drying blanks after bending. The curved workpieces are dried in drying chambers to operational humidity, and the workpieces are placed in the chamber together with templates and tires covering them. The design of drying chambers is similar to those used for drying lumber.

The dried workpieces are unloaded from the chambers and sent to the cooling compartment, where they are kept for at least 48 hours to equalize internal stresses. Only after this the workpieces are freed from templates and tires and sent to the machining shop.

The sequence and principles of mechanical processing of bent workpieces on machines, i.e. Giving them final dimensions and a clean surface is not fundamentally different from processing straight workpieces.

Production of bent-glued parts. To obtain bent-glued parts, hydrothermal treatment of wood before bending and drying after bending are not required. Bent-glued parts are made from peeled veneer or plywood. The technological process for producing bent-glued parts consists of preparing raw materials (veneer, plywood or thin strips), applying them to the surfaces to be glued adhesive solution, gluing workpieces with simultaneous bending in molds or templates and holding parts after pressing to equalize moisture and stress.

Bonding is done either in blocks or in separate parts. Pressing is carried out in hydraulic presses with molds or templates. Use one of three types of heating of the compressed bag: electric contact, steam or currents high frequency(HDTV). HDTV heating is the most progressive. This method requires less pressing time and the temperature is distributed more evenly across the cross section of the bag.

Adhesives based on high concentration urea resins and increased speed curing. The consumption of such adhesives per 1 m2 of surface to be spread is 110-120 g.

If there is a need to make a curved wooden element, then at first glance it may seem that it would be easier to cut necessary element in a curved form, but under such conditions the fibers of the wood material will be cut, thus weakening the strength of the part, and as a consequence, the entire product. In addition, when sawing, there is a huge waste of material, which cannot be said about the method, while the wooden blank is simply bent.

Wood is cellulose fibers bound together by a chemical called lignin. The flexibility of the tree depends on the placement of the fibers.

Only well-dried wood will be a reliable and durable source material for the production of various products. But changing the shape of a dry wooden blank is a difficult process, since dry wood can break, which is very undesirable.

Having studied the technology of how to bend wood, and the fundamental physical properties of wood, which allow you to change its shape and then preserve it, you can fully engage in bending wood at home.

Some features of working with wood

Bending of wood is accompanied by its deformation, compression of the inner layers and stretching of the outer layers. It is not uncommon for tensile forces to cause the outer fibers to break. This can be prevented by preliminary hydrothermal treatment.

So, it is possible to bend blanks of timber made from solid and laminated wood. In addition, planed and peeled veneer is used for bending. The most plastic are hardwoods. These include beech, ash, birch, hornbeam, maple, oak, poplar, linden and alder. It is best to make bent glued blanks from birch veneer. It must be emphasized that in the total volume of bent-glued blanks, birch veneer occupies approximately 60%.

When steaming the workpiece, the compressive property increases significantly, namely by a third, while the tensile property increases by only a couple of percent. This means that one should not think a priori about whether it is possible to bend a tree thicker than 2 cm.

Steam box heating

First, go prepare the steam box. It may have been made by hand. Its main task is to hold the tree that needs to be bent. There should be a hole in it to allow the steam pressure to escape. Otherwise it will explode.

The steam outlet should be located in the bottom of the box. In addition, the box should have a removable lid through which it will be possible to pull out the bent wood once it has taken the desired shape. In order to hold the bent wooden part in the desired shape, use clamps. You can make them yourself from wood or purchase them at a specialized store.

It is necessary to make round trimmings from the wood - a couple of pieces. Off-center holes are drilled in them. Then you need to push the bolts through them, and after that drill another hole through the sides in order to push them in tightly. Such simple crafts can become excellent clips.

Now is the time to steam the wood; to do this, take care of the heat source and close the wood piece in the steam box. For every 2.5 cm of thickness of the workpiece, the product needs to be steamed for about an hour. At the end of the time, the tree must be removed from the box and given the desired shape. The process should be completed very quickly. The workpiece is bent carefully and softly.

Some types of wood bend more easily than others due to different elasticity. Various methods require the application of force of varying magnitude.

When the desired result is achieved, the bent tree must be fixed in this position. It is possible to secure the tree during its formation. That is why it is easier to control the process.

Using chemical impregnation

In order to destroy the lignin bonds between fibers, it is possible to influence the wood with chemicals, and this can be done to the fullest extent at home. Ammonia is ideal for this. The workpiece is soaked in a 25% aqueous ammonia solution. At the end of which it becomes very obedient and elastic, which allows you to bend, twist it and squeeze out relief shapes in it under pressure.

Ammonia is scary! Based on this, when working with it, you should follow all safety regulations. The soaking of the workpiece should be carried out in a tightly closed container located in a well-ventilated room.

The longer the wood is in the ammonia solution, the more plastic it becomes. After soaking the workpiece and giving it shape, it is necessary to leave it in this curved form. This is necessary to fix the shape, and so that the ammonia evaporates. Again, bent wood should be left in a ventilated area. It is noteworthy that after the ammonia has evaporated, the wood fibers will regain their former strength, and this will allow the workpiece to retain its shape!

Layering method

First you need to make a piece of wood that will be bent. The boards should be slightly longer than the length of the finished part. This is explained by the fact that bending will shorten the lamellas. Before you start cutting, draw a diagonal line with a pencil. This must be done across the underside of the board. This will allow the lamella sequence to be maintained after they have been moved.

The boards are cut with a straight edge, never with the right side. So, it will be possible to put them together with the slightest transformation. A layer of cork is applied to the mold. This will help avoid unevenness in the shape of the saw, which will allow you to make a clearer bend. In addition, the cork will keep the delamination in shape. Now glue is applied to the top side of one of the wooden slats.

The glue is applied to the lamellas with a roller. It is best to use urea-formaldehyde glue, which consists of 2 parts. It has a high level of adhesion, but takes a long time to dry. It is also possible to use epoxy resin, but such a composition costs a lot, and not everyone can afford it. Regular wood glue cannot be used in this case. It dries quickly, but is very soft, which is not welcome in this environment.

Place the bent wood blank into the mold as quickly as possible. So, another lamella is placed on top of the glue-coated lamella. The process is repeated until the bent piece reaches the desired thickness. The boards are fastened together. Once the glue has completely dried, proceed to shorten it to the desired length.

I drank it as a way

The prepared piece of wood must be sawn through. The cuts are made 2/3 of the thickness of the workpiece. They should be on the inside of the bend. Be extremely careful, as rough cuts can break the tree.

The key to success when cutting cuts is to keep the distance between cuts as even as possible. Perfectly 1.25 cm.

The cuts are made across the grain of the wood. Then try to squeeze the edges of the workpiece so as to connect the gaps together. This is the shape the bend will take upon completion of the work. After this, the bend is corrected. Much more often, the outer side is treated with veneer, or in some cases with laminate. This effect allows you to correct the bend and hide any flaws made during production. The gaps between the bent wood are easily hidden - for this, glue and sawdust are mixed, and when finished, the gaps are filled with this mixture.

Regardless of the bending method, once the wood is removed from the mold, the bend will easily relax. In view of this, it needs to be made a little more in order to compensate for this effect later. The sawing method can be used when bending part of a box or an iron corner.

So, using these simple tips It is possible to bend a tree with your own hands without much effort.