Thermowood is a modern and beautiful finishing material. Properties of a heat-treated board, or thermowood

Thermal wood (heat-treated board) is a unique type of wood panels that has rapidly burst into the construction market and has taken a leading position among natural wood finishing materials. Thermal wood is distinguished by improved characteristics and an extended area of ​​​​use.

The production of thermowood is characterized by the process of thermal processing of softwood and hardwood blanks. Most often, oak, ash, pine, and less often spruce become the basis for manufacturing.

Prolonged exposure to temperature, which thermowood is exposed to, makes it hollow. The manufacturing technology is quite simple in the sense that during processing, wood is deprived of cellulose and resins.

At the same time, the structure of the wood fiber changes and is modified into a kind of caramelized mass, which leads to high performance properties.

Manufacturing includes the following steps:

1. Drying of workpieces. The stage takes place in a special vacuum box, where air is pumped out and slowly warmed up to a temperature of +180°C. The stage is characterized by the formation of steam in the chamber.
2. Processing of blanks, or the so-called increase in biostability. The steam generated at the first technological stage is enriched with chemical reagents. In this case, the boards are exposed to high pressure, which, in combination with reagents, contributes to the decomposition of cellulose fibers. That is, there is a molecular change in the structure of wood. As you know, it is hemicellulose that becomes a breeding ground for the reproduction of fungus and mold - in thermal wood, this possibility is excluded.
3. Workpiece stabilization. The stage is characterized by the crystallization of cellulose fibers.

https://youtu.be/vEcoPOCkTyw

Heat treatment of wood can be carried out using four technologies:

1. Processing in one step. With this method, the workpieces are processed with heated steam at a temperature of 150° to 200°C, under the influence of which the oxygen content of the box decreases to 3.5%. Both pre-dried and raw blanks can be subjected to one-stage processing. The processing of dried wood takes about 3 days, and raw wood takes several days longer.
2. Multi-stage treatment under the action of heated steam and pressure. It takes place in a sealed box at a temperature of +150-+200°C and a pressure of at least 1.6 MPa. Drying is carried out within 4 days. The moisture content of finished products should not exceed 10%.
3. Treatment with vegetable oil. The technology involves placing blanks in a container filled with vegetable oil and slow heating. At the same time, the wood structure is saturated with a small amount of oil, which makes the thermowood moisture resistant and resistant to cracking.
4. Nitrogen treatment with 2% oxygen or other inert gas. The process is called refining. This technology allows to obtain products of the highest quality.

Among the finishing materials, heat-treated wood, which is distinguished by unique performance characteristics, aesthetic appearance and a wide range of applications, has received wide demand and popularity on the market. Thermal wood is an excellent analogue of natural wood.

Properties and scope

Wood is an environmentally friendly natural material that has an excellent texture and is absolutely safe for human health. However, without additional processing, the tree is not able to withstand adverse external factors such as high humidity, the action of biological microorganisms and insects.

The modern method of processing wood raw materials, thermal modification, has made it possible to obtain a new high-quality finishing material, which has found wide demand in the market. Thermowood is lumber that has undergone additional heat treatment at a temperature of 180 to 240 degrees without the use of synthetic additives and compounds.

Thermowood is a unique finishing material that combines an environmentally friendly composition and amazing physical and mechanical properties:

• Dimensional stability when exposed to adverse factors environment - temperature and moisture (in contrast to untreated wood, this indicator improves by 10-15 times, the reduction in the risk of swelling in a humid environment is reduced to 90%).
• Hygroscopicity. The moisture content of wood is reduced to 4-8 percent, which is significantly lower compared to the industrial drying of lumber in special chambers. The ability to absorb moisture in thermal wood is reduced by 5-6 times. With a long stay in a humid environment and directly in water, the maximum moisture content of the raw material does not exceed 9-10 percent, natural drying occurs almost instantly.
• Long service life resistance to biological damage. Processing wood at high temperatures leads to the decomposition of polysaccharides, which, given the low moisture content of the raw material, minimizes the risk of damage by microorganisms, mold and fungus.
• High thermal conductivity. Thermal wood is an ideal material for baths and saunas, as its thermal insulation characteristics are 30 percent higher than those of natural wood.
• High density wood provides water repellency without additional processing, lumber does not absorb moisture from the air. Wood after heat treatment is resistant to mechanical stress.
• environmental cleanliness, absolute safety for the human body and the environment.
• High fire safety. The hardness and density of heat-treated wood cause a slow fire of the raw material.
• Aesthetic appearance of thermal wood. After heat treatment, the decorative properties of lumber are noticeably improved - an effective wood structure and a noble dark shade appear. Heat treatment gives even inexpensive wood species the appearance of valuable species.

Thermal wood is widely used for interior and exterior decoration of houses, baths and saunas. Due to its high strength, dimensional stability and resistance to adverse external factors, the facade made of thermally treated wood will not lose its original appearance even after a long time.

However, the high cost of lumber makes it economically inexpedient for use as an interior decoration (wall and floor decoration). Thermally treated wood is most in demand in the following areas: facades, terraces, open street areas, verandas, gazebos, fences, railings, decorative items (flooring, outdoor furniture).

The only disadvantage of lumber is its high brittleness. Sawing of thermal wood should be carried out with a special tool with fine teeth at high speeds with a small feed of the workpiece. Failure to comply with the conditions and requirements for sawing leads to the fact that the workpiece bursts.

Do-it-yourself thermowood production technology

Modern technology for the production of thermowood involves a long-term exposure to high temperatures on hardwood and coniferous blanks. Mostly used species such as pine, oak and ash, in more rare cases - spruce.

Under the influence of high temperatures, the structure and density of wood changes, as a result of which it becomes hollow. Polysaccharides, resin, cellulose are almost completely burned out of wood, and lumber fibers are modified (“caramelized”).

The manufacture of thermowood in industrial conditions and with your own hands is carried out in three stages. At the first, forced drying of the blanks is carried out to reduce the level of moisture as much as possible. The duration of wood drying depends on the type of raw material used and the size of the workpiece.

The production of thermowood is carried out using several methods:

• Single stage. Standard processing of lumber under the influence of heated steam up to 180-200 degrees.
• Multistage. Processing wood with superheated steam under pressure is carried out in several stages. This thermowood production technology is mainly used for pre-dried raw materials. At the first stage, the blanks are processed with hot steam in a pressure chamber, at the second stage they are additionally dried.
• Hot oil treatment. The lumber blanks are placed in a container with oil, after which they are slowly heated. During processing, wood absorbs a small amount of oil, which increases its resistance to moisture.
• Processing in the environment of inert gases. Processing workpieces in nitrogen at high pressure and reduced oxygen content. This method allows you to get thermowood of the highest quality.

The technology for the production of thermally treated wood involves the impact on the workpiece of superheated steam at a temperature of 150 to 240 degrees, which makes it possible to classify the finished thermal wood into three groups:

• First grade. Processing of raw materials at a temperature of not more than 150 degrees, the finished lumber has a slightly tinted shade and the lowest technical and operational characteristics;
• Second class. Wood is treated with steam at a temperature of up to 210 degrees, lumber acquires high strength and hardness, resistance to decay and decomposition. The shade of wood is more saturated;
• Third class. The highest class of thermally treated wood, after firing at a temperature of up to 240 degrees, lumber receives the highest strength, hardness and resistance to adverse external factors.

Heat treatment of blanks is carried out in special closed chambers for 24 hours. Heated steam acts as a protective environment, it prevents the burning of lumber and actively participates in chemical reactions.

At the last stage of making thermowood with your own hands (hardening), the lumber is subjected to prolonged cooling with constant monitoring of the percentage of moisture in the wood (at the level of 6-7 percent). Wood does not require final processing.

Thermowood, having worthily proven itself as a modern finish for saunas and a number of objects of our private and corporate clients, is ideal for interior and exterior cladding of houses, saunas and baths, installation of floors, including modular parquet, open terraces, patios, garden paths and pool areas, production of stairs, interior items, as well as garden furniture, landscape design elements and fences.

To make thermowood more durable, we recommend that you always cover the boards with compounds that protect against exposure to sunlight.

Thermal wood burns out in the sun, and protective finish coatings can not only additionally protect it from environmental influences, make it brighter, emphasize the structure favorably, but also protect it from ultraviolet radiation.

The treatment increases wear resistance, reduces the possibility of cracking and revitalizes the surface.

Please note that before the installation of street structures, the boards should be covered with the selected composition from all sides, following the manufacturer's recommendations at a temperature not lower than + 16-18 degrees. Before starting work, it is recommended to clean the surface from dust and dirt.

• Tikkurila Valtti wood oil;
• Special oils for wood Osmo.
• For thermal wood in baths and saunas, Supi Laudesuoja's Tikkurila oil is suitable to protect the shelf.

The great demand for building and finishing materials made of wood is associated with cleanliness, environmental friendliness and good qualities of wood. In recent decades, other raw materials have been actively developed that are not affected by moisture, deformation, decay and other defects. However, synthetic products often take up the useful properties of wood, so developments to find new ways to increase the durability and qualities of natural material continue to this day. The pinnacle of hardening beams, boards and other lumber is the heat treatment method.

Wood heat treatment technology

For the first time, the method of heat treatment of wood appeared in Finland. It was the inhabitants of this country who discovered an increase in the resistance of the material to atmospheric influences as a result of the heat treatment of birch, if, pine and aspen.

According to their methodology for the process, it is necessary to carry out the material through several stages:

1. Elimination of moisture from timber fibers due to drying in closed chambers at temperatures from 130 °C to 150 °C.
2. At high pressure with the use of water vapor, the thermal strengthening of lumber continues at temperatures from 200 ° C to 240 ° C. At this stage, the wood is painted in a characteristic shade.
3. Lowering the temperature with bringing the percentage of moisture content in the fibers to a level of no more than 4-6%.

As a result of such a finishing cycle, the timber gets a new texture, changed at the molecular level. This is due to the splitting of the fibers and the bonds between them, as a result of high pressure and temperature. Thus, the surface becomes less porous, it is able to withstand moisture, less responsive to deformation under heavy rains, and does not require additional protective coating. Also, the thermal tree can boast of transferring high temperature fluctuations and humidity surges by 10-15 times.

The color of wood after such processing becomes close to the shade of expensive varieties. Even from the simplest cheap piece of wood, you can make a material similar in appearance to larch or other expensive species. The change in structure improves resistance to rot, mold and insect infestation, which increases the life of wooden elements by an average of 20 times compared to their natural counterpart.

Advantages of thermowood

• Environmentally friendly origin.
• Smells like wood with no odors.
• Withstands significant temperature fluctuations.
• It has a low shrinkage rate.
• Long service life.
• The surface quality is very high.
• Throughout the transverse and longitudinal section of the material, the same tone corresponds to the external color.

Due to the significant expansion of the temperature regime of timber processing, there are the following classes of thermowood:

• Class 1. The material with the lowest performance and light degree of tinting, due to processing at temperatures up to 190 ° C.
• Class 2 The timber gains high strength and decay resistance with a darker color, however brittle and less ductile due to the treatment at 210°C.
• Class 3. The highest quality lumber with high resistance to aggressive environmental influences, hardness and density. They have a uniform dark shade and a noble surface texture. Produced at 240°C.

Heat Treatment Equipment

There are many manufacturers of thermowood equipment that use different technologies for the specific wood firing process. The most popular brands are:

• Vacuum Plus;
• Bikos-TMT;
• fromseier;
• Menz Holz;
• Retification;
• PLATO;
• Thermowood;
• Westwood.

Differences and features of thermal chambers

Heat Treatment Chamber

The equipment is a tightly closed tank of a certain volume, into which lumber is loaded on special stands. It is necessary to provide the possibility of steam access to all surfaces of the board or timber. During the processing cycle, depending on the technology in the chamber, the material is subjected to drying at high temperatures, evacuation of air or the introduction of inert gas, organic oils, firing at extreme temperatures and moisture correction.

Each thermal chamber must be characterized by the following parameters:

1. The level of security and specifics of managing the operation of the device.
2. Permissible moisture level of the feedstock.
3. The duration of the full cycle (depends on the technology, type of wood, method of pre-treatment of lumber).
4. Permissible dimensions of the cross-section of the beam, in which the raw material will receive a uniform color throughout the thickness.
5. Energy costs and other required resources for the heat treatment process.
6. Overall dimensions and volume of the working area, which allows you to increase the amount of wood processing in one cycle.

Heat treatment of wood at home

Creating a heat chamber by a handicraft method implies the presence of the following components:

1. A tightly closed container that will not allow oxygen to get inside during the heating process.
2. Energy supply methods: electric, gas or solid fuel heating of the chamber cavity.
3. Containers with water to create the desired level of humidity inside the work area.
4. Tools for working with metal, electrical and gas equipment.

The principle of operation of the device is to introduce a container of water into the chamber, which will evaporate as a result of an increase in temperature, preventing the ignition of sawn timber in the mode from 135 ℃. The chamber must be heated so that the desired high temperature is established inside. Most often, an electric heating method is used for this. The ingress of oxygen increases the risk of wood fire, so the chamber must be securely and tightly closed.

An example of such crafts can be found on various forums of craftsmen. Some present their creations from railroad tank cars with complex internal structures to install materials. However, at home, small pieces of wood can be processed differently. It is enough to boil the workpiece for about an hour and a half in ordinary water, and then wrap it in warm old clothes or newspapers. In this form, continue drying near the stove or other source of heat. This method has been used for many hundreds of years by wood carvers to harden linden.

Conclusion

Thermowood is still a material of natural origin, as evidenced even by its smell. For the outer surface, the material does not require additional finishing and coating. It is highly resistant to precipitation and temperature extremes, which allows you to start a new era of wood in human housing. Most importantly, windows and doors made of thermowood will last for decades without loss of quality and appearance.

One of the progressive directions in the development of building technologies is the development and introduction of new materials with high performance characteristics. These innovations include thermal wood. It is endowed with positive characteristics, which include the following parameters:

• natural base;
• super-resistance to the influence of the external environment;
• no need for additional processing with aggressive chemicals.

Such properties make the process of thermal modification of wood and its result quite popular for various applications. For example, durable thermowood windows are already on the market.

Production steps

Thermal wood is produced in Moscow or another city on special equipment. At the same time, no additional components are provided by the production technology. Heat treatment of wood is carried out due to the effect of water vapor on raw materials placed in a sealed chamber. Blanks are made from oak, ash, beech, walnut, less often pine.

Initially, the technology of heat treatment of wood in its modern form was developed by Finnish specialists. The prepared raw material in a closed module in the absence of oxygen access is subjected to a multi-stage effect of steam heated to 185-212 C.
Such progressive heat treatment of wood has become used not only in Europe, but also in Canada and Russia. The following steps are involved:

• Workpiece heating. First of all, the equipment for thermal wood heats the material placed inside to 13-150 C. Then, by boiling, the wood is exposed to steam for 5 hours.
• Drying. Heat-treated lumber is dried, reducing the moisture content of the raw material to 10%. Thermally modified wood in the drying equipment remains for 2-3 days to achieve optimal parameters.
• Excerpt. In closed conditions, the temperature is increased and saturation with water vapor at elevated pressure. This process of thermo-modified wood technology gives the hardness characteristic of the material and a unique color. The palette changes depending on the thermal regime, and not on the duration of processing. The resistance to external influence of moisture increases, putrefactive phenomena are excluded and no further deformation occurs.

Technology features

It should be borne in mind that the mode at 190 C will only provide a decorative effect, without significantly affecting performance.

In most cases, heat treatment is carried out in the mode of 200-230 C. Thus, the resistance to decay increases several times. This material can be used in the production of furniture, decor, window frames, interior doors.
The price of thermally modified wood that has been exposed to more than 230 C will be higher, since its properties will noticeably improve. The board will receive resistance not only to rotting, but also to swelling. As a result, the material can be used for almost any outdoor work or aggressive environment, for example, in swimming pools, saunas, baths, etc.

In Germany, wood heat treatment, the price of which varies depending on the type of wood, the technology used, and can range from 25,000 rubles. up to 80,000 rubles per cubic meter, carried out in an oily environment. The edged dry board is placed in oil at 180-220 C, keeping for 3-4 hours.
How to make a thermowood with your own hands is presented in the video.

There is also a technique for processing boards in inert gases and a nitrogen atmosphere at elevated pressure. The oxygen level should not exceed 2%.

Comparative characteristics of wood thermal modification technologies are presented in the table.

Is it possible to dry a beam to a moisture content of 6% in 72 hours and get a thermal beam with a section of 300x300 mm? Wood drying experts say no. But in the research and production association "Pobeda" they say that this is possible - using a camera developed at the NPO for wood modification. Oleg Shulman, general director of the DrevTermo trading house (co-founder of NPO Pobeda), told a correspondent of our magazine about the peculiarities of the operation of the thermal chamber.

— Oleg Isaakovich, please tell us why you decided to develop equipment for heat treatment?

— The Russian consumer has been familiar with thermal wood for more than 15 years, and every year the scope of its application is expanding. Thermowood has established itself in the domestic market as a modern material for exterior and interior decoration of houses, saunas and baths, as a material for the manufacture of floor coverings, coverings for terraces, patios, garden paths, areas near pools, stairs, interior items, as well as garden furniture, landscape design elements and fences. We analyzed the existing heat treatment technologies (Bikos-TMT, Vacuum Plus, Mirako, Fromsseier, Menz-Holz, Retification, Plato, Thermowood) and came to the conclusion that their main disadvantages are increased requirements for the quality of raw materials (wood must be at least the first varieties) and high energy consumption (heat treatment can take up to 20 days). None of the technologies used makes it possible to obtain a thermally modified timber or a log of low cost in a short time.

A few years ago in our country they began to produce thermal beams. Enterprises of wooden housing construction became interested in this material. Given the popularity of thermal modification technology in Russia, our research center conducted a survey of house-building companies, which confirmed the demand for heat-treated timber or logs, as well as the desire to manufacture them at their own production facilities.

— What is the peculiarity of your technology?

— The technology developed by the engineer of our scientific center Oleg Moichkin, in comparison with those that are common now, has differences in the methods of heating wood and removing moisture. The thermal regimes are worked out in such a way that it is possible to use raw materials with a moisture content of up to 100% (freshly cut), pre-drying of wood before heat treatment is not required. Thermal modification is carried out in just one cycle, its duration depends on the type and size of the processed material, and according to existing technologies, heat treatment is performed in several stages. Reducing the duration of heat treatment allows you to reduce the cost of electricity to 1200 rubles/m 3 . The minimum costs that fall on energy resources, according to existing technologies, are 5000 rubles / m 3.

According to the laws of thermodynamics, the heat treatment of 1 m 3 of wood requires at least 250 kW of electricity. The processes occurring in the chamber cannot be described by these laws, since the efficiency of our chamber approaches 200% (according to existing technologies, the efficiency of the chamber does not exceed 80%). Based on the results of research into the structure of the electrical substance by the scientist Yuri Rybnikov and his periodic table of electroatoms, the result obtained is quite understandable.

— Is your technology similar to what Thermowood presents on the market?

— Finnish Thermowood technology cannot be compared with ours: they are different. The study of methods of processing wood and its drying has been done for a long time. But in fact, the processes that describe a particular physical process cannot be reproduced in practice with 100% accuracy. The classification of types and methods of drying is usually based on the methods of heat transfer. In our thermal chamber, the wood is subjected to simultaneous treatment with infrared radiation, convective and conductive drying. Energy consumption is minimal due to the fact that no electricity is required to start or end one of the heating processes. Thermal modification of wood takes place in an environment of superheated steam. In the process of heat treatment, the wood acquires a rich noble brown hue, uniform throughout the entire section. After thermal modification, the material can be immediately machined and coated with paints and varnishes.

- Under what conditions is the heat treatment of the beam?

- At the moment, the thermal regimes have been debugged for obtaining a thermal beam from birch, pine, spruce, linden and aspen wood. For the processing of aspen wood, more parameters must be taken into account than for wood of other species in order to reduce internal stresses in the resulting material. A beam with a cross section of 300×300 mm is better to be thermized at a temperature of 160-170°C for 72 hours. In this mode, the bending and chipping strength of wood is slightly reduced. The high processing temperature (180-200°C) makes it brittle, it also darkens greatly, which worsens its aesthetic qualities. It takes different times to process the wood of the species mentioned above, but the difference is only a few hours. In addition to the thermal beam, the chamber is designed for processing rounded logs (up to 30 cm in diameter) and lumber. The volume of one-time loading of the chamber is 5 m 3 , after processing the volume of finished products is 3.5 m 3 .

- For the industrial production of house kits, a chamber with a volume of 5 m 3 is small. Are you planning to expand it?

“Since the ongoing processes cannot be described using mathematical algorithms, and when creating a large-volume chamber, it will be necessary to work out thermal modification modes, the parameters of which will be calculated taking into account the large volume of processed wood. We are already working on the creation of chambers with a one-time loading capacity of 10-12 m 3 and 20-25 m 3 .

How are camera modes controlled?

- Now the camera is controlled by the simplest automation, and the heat treatment mode is adjusted manually. By increasing the size of the chamber, all processes will be fully automated. It will be enough for the operator to set the necessary parameters before loading the raw materials, close the chamber, and after the process is completed, unload the heat-treated materials.

- How is the camera installed at the existing enterprise for the production of prefabricated wooden houses?

- The camera is quite easily and quickly integrated into the existing technological process. If a company is engaged in the manufacture of house kits from profiled timber, then additional space will be needed to install the camera, and the machines that are in the production for the processing of profiled timber can also be used to process thermally modified material. There are no restrictions. The production of a new type of product - thermal beam - allows you to expand the range of products manufactured by the enterprise, and does not create difficulties in work. In its price segment, heat-treated timber or logs will compete with glued laminated timber, and in the construction of wooden houses from profiled timber, they will replace the latter.

— You said that the company would need additional space just to install the camera. What exactly?

- A chamber with a loading volume of 5 m 3 occupies about 9.5 m 2, its length is 6.7 m, its width and height are 1.5 m. For an industrial enterprise, this is a small area.

- Substances that are released from wood during heat treatment are environmentally unsafe. How is the issue of disposal of waste generated in the process of wood modification being solved?

— Special recycling systems are installed on our chambers, so no harmful substances are released during the heat treatment, which indicates the environmental safety of the process.

- Usually, after high-temperature processing, wood acquires a burning smell. Does your thermal beam or thermal log have it?

– Pyrolysis products, which are formed during the thermal modification of a beam or log, are removed during processing, which allows, after thermal treatment, to immediately transport the material to the construction site, and not keep it in a warehouse to remove odors.

- What will be the characteristics of the building material after heat treatment?

Products from thermally treated birch wood

Thermal birch souvenir

— Thermobeam and thermal log have the same characteristics as thermal board and thermolining: dimensional stability, increased hygroscopicity, biological stability, low thermal conductivity, environmental safety, aesthetics.

If we are talking about a thermal beam, then this product is a substitute for a profiled beam of natural moisture. Heat treatment reduces construction time to three years: the humidity of the thermal beam is about 6%, so there is no need to assemble the walls of the house and then wait for them to shrink. The increased biostability of the timber after thermal treatment excludes the treatment of the walls of the house with compounds that protect the wood from damage by microorganisms or insects. As I said earlier, low energy costs result in a lower cost of finished products, which can reduce the cost of building a solid wood house by up to 30% when compared to the cost of building a glulam house.

A beam with a section of 300x300 mm is laid in the heat chamber, and after mechanical processing its cross section will be 260x240 mm, the effect of elevated temperature on wood can reduce the thermal conductivity of the material and increase thermal insulation characteristics, which are its advantages over glued beams.

After heat treatment, the geometric dimensions of a beam or log do not depend on variable temperature and humidity conditions (for example, precipitation). Therefore, you can build a house at any time of the year. In accordance with the results of preliminary tests carried out by our specialists, the thermal characteristics of a house made of thermal timber or logs are 20-30% higher than the thermal characteristics of a house made of glued or profiled timber.

video instruction on how to make, features of tinting, how to paint, give the effect of aging, price, photo

All photos from the article

The consumer has played enough with modern materials, and the “sterile” plastic European-quality repair has put many on edge. To dilute the refined style of fashionable coatings, some wooden parts of the interior and furniture should be aged. We will tell you how to give the effect of antiquity to a tree at home.

Antique wood processing allows you to create the effect of vintage furniture and a luxurious interior.

Method features

The photo shows an example of aged garden furniture.

Before processing a semi-antique wood, it is advisable to study and understand the methodology of this process. We are faced with the task of simulating the natural aging of the material, so let's figure out what exactly happens in this case.

The wood is heterogeneous and consists of many layers, which are visible on the cut in the form of so-called annual rings. These layers are formed during the growth of the plant.

And due to the fact that this growth occurs in various temperature and weather conditions (noticeable fluctuations in weather and temperature indicators are observed from year to year), the density and strength of the layers differ significantly.

Wood consists of many layers of different density.

During the operation of the material, it is subjected to a number of different destructive factors, including erosion under the influence of precipitation, wind, solar radiation, etc.

Since the layers have different strengths and densities, they are destroyed unevenly:

• softer faster;
• stronger - slower.

As a result, the surface of the material acquires a characteristic relief, which distinguishes old wood from young wood. In addition, the fibers change color: some darken more, others turn yellow, individual layers remain light. This is how the patina appears.

In the process of aging, relief and patina appear.

Thus, we are faced with the task of achieving a similar effect, namely:

1. To subject the material to such an impact, as a result of which the layers of wood will be destroyed, which, taking into account the heterogeneity of their physical characteristics, will lead to the appearance of a relief. Of course, this must be done in an accelerated mode compared to natural erosion;
2. Give the surface a color similar to the change in natural color as a result of prolonged exposure to the environment. In other words, we must produce artificial patination.

Board after artificial processing.

There are several ways to simulate the natural erosion of a material:

• Mechanical restoration. Using abrasive tools such as metal and nylon brushes, aging-like relief can be created;
• Heat treatment. Helps create relief and change the color of the fibers. Blowtorches and gas burners are used;
• Chemical processing. Solutions of strong alkalis corrode cellulose, creating uneven destruction in different layers.

Patination is carried out using various oils, paints, waxes and stains. Next, we will show you how to paint antique wood with the simplest tools.

Patination with wax.

Important! The price of antique-finished furniture and building lumber is very high. With the help of our guide, you can create them yourself from the most ordinary wood.

Antique wood processing

Mechanical

Mechanical processing is the most effective way of aging.

Mechanical aging is called wood brushing, from the English word "brush" - "brush". Accordingly, an abrasive brush should be used for work.

Roughing with a grinder.

The process consists of three main steps, which are outlined in the following table:

Sanding with a nylon brush.

Important! First, you should practice cutting the board in order to understand the nuances of the process, feel the pressing force and select the desired abrasive caliber.

Thermal and chemical

Piece of timber after firing.

Another popular way to give wood the effect of antiquity is firing. Since the layers of the material have different physical and chemical characteristics, as a result of exposure to high temperatures and flames, they burn out with different intensity.

For work it is best to use a gas burner. Gasoline blowtorches smoke a lot, which can add extra work to us.

A fairly inexpensive Chinese burner with a cylinder.

So let's get started. We take a board and begin to burn it with a flame of a gas burner. We make sure that the material does not flare up, but is evenly charred over the entire surface.

The degree of charring is selected individually depending on the type of wood and the desired effect. Typically, the surface is brought to a substantially solid black.

The photo shows the approximate degree of charring.

After the board has cooled down, it is subjected to grinding with the help of the same brush. It is necessary to remove carbon deposits so that some layers become light, others remain slightly darkened, and still others are completely black.

Important! A distinctive feature of the method is the fact that as a result the board does not need additional tinting. Although, it can also be appropriate.

During chemical treatment, a concentrated solution of alkali such as caustic soda or potassium is applied to the surface. The board is left for a long time, which depends on the chemical used and the type of wood.

Then the alkali is washed off with water and a weak solution of acetic or citric acid, and subjected to the grinding described above.

Preparation of alkali solution.

Toning

Antique wood tinting with wood stain.

Wood darkens over time. Therefore, it is better to use pigments of dark shades for work. It can be interior oil, acrylic paint, stain or wax.

Applying oil to the treated board.

First, paint or oil is applied with a brush to the entire surface, quite abundantly. Then they take a cotton rag and erase the pigment from the protruding fragments of the relief, giving the surface an expressive texture.

Wipe the top layer with a cloth.

Finally, the surface is covered with a transparent varnish for coloring wood, which flows into the recesses and smoothes them. This work can be considered completed.

Conclusion

Wooden products can be quite easily aged at home using simple tools. The video in this article demonstrates the entire process in detail.

rubankom.com

STROJABC.RU - Heat treatment of wood

As you know, wood is a beautiful, but capricious material. Fluctuations in temperature and humidity, fungi and mold - all this can seriously degrade the quality of wood. Therefore, it is customary to process a tree before use, and until recently, processing was understood only as a chemical effect, which did not have the best effect on the environmental friendliness of the resulting wood. Since 2004, the EU has banned the use of chemically treated wood. At the same time, technologies for heat treatment of wood, which are an alternative to chemical ones, began to be mastered.

To date, there are several methods of heat treatment of wood. All of them are based on the use of very high temperatures, but otherwise they differ. So, the very first method of thermal action is based on the processing of wood in air at a temperature of 200-240°C. Another technology involves the use of saturated steam, increasing the pressure and temperature to 185-212°C. There are also methods of thermal impact on wood in nitrogen or oil environments.

What is the heat treatment of wood? Under the influence of high temperatures, a number of wood parameters are improved:

• Heat-treated wood has increased water repellency, which prevents the wood from rotting. Resistance to rotting is also connected with the fact that at a processing temperature above 2000 C, the chemical decomposition of semi-cellulose and lignin occurs, which is simply impossible with conventional drying.
• As a result of a decrease in the moisture level of wood, its heat capacity sharply decreases (by 10–30%). As a result, heat-treated wood heats up very slowly, which is important, for example, for baths.
• Heat-treated wood is more stable. During operation, it tolerates changes in air humidity much better.
• The heat treatment process significantly increases the resistance of wood to biological damage (the reproduction of fungi and microorganisms)
• The degree of deformation due to weather conditions in heat-treated wood is 20-90% less than in untreated wood.
• Under the influence of high temperatures, the wood acquires magnificent shades. The most common types of wood for our latitudes, such as pine or birch, after heat treatment, in their appearance resemble exotic species.

Wood also has its drawbacks. So, increased temperature reduces the elasticity of wood, as a result of which it becomes more fragile than usual. Therefore, for the device of load-bearing structures designed to withstand heavy loads, it is better not to use thermal wood.

Heat treated wood - WikiStroy

In 1997, a new technology was introduced at one of the Finnish woodworking factories in Mikkeli, which was called<термообработка>. With this technological process, drying is carried out at a temperature of 150 - 230 degrees. The higher the temperature, the greater the weight loss due to the evaporation of volatile compounds (in other words, the wood becomes lighter). The greater the weight loss, the less water remains in the wood. Depending on the conditions of heat treatment and the type of wood, the residual moisture content of wood is 40 - 60% less than that of conventionally dried wood.

The heat treatment process usually takes about 24 hours. The moisture content of wood after heat treatment is reduced by 80 - 90%. As a result, its heat capacity is significantly reduced: heat-treated wood heats up much weaker than untreated wood, approaching abash in this indicator. The surface of heat-treated wood is not porous, but dense, which significantly reduces the wood's ability to absorb moisture from the air (by 30% - 90% depending on temperature and drying time).

In practice, this means that the tree is able to repel water without additional treatment with special impregnations. During heat treatment, wood sugars decompose, which are a breeding ground for microorganisms that contribute to wood decay. It becomes extremely resistant to decay, approaching larch in this indicator, and, consequently, a hygienic material.

It should be especially noted that coniferous woods almost completely lose their resin, retaining a wonderful aroma, which intensifies with increasing humidity and air temperature.

During heat treatment, the wood changes color, acquiring a beautiful brown tint. It should be noted that the color change is through, which is clearly visible on the cut. Scratches on such a surface are almost invisible. By varying the heat treatment temperature, it is possible to achieve the desired shade of wood and / or degree of resistance to environmental conditions.

Where is heat treated wood used?

Due to the beautiful appearance and unique properties of heat-treated wood, it can be used in many areas, including sauna interiors, building exteriors, flooring, both parquet and plank, garden furniture, boats, musical instruments, etc. P.

From the point of view of planetary ecology, heat-treated wood (including coniferous wood) as a material for shelves in a sauna and a bath is a worthy alternative to the traditional abash-sambo, which grows only in equatorial evergreens, the so-called<дождевых>forests - the main source of oxygen in the Earth's atmosphere, which cannot be restored."

What happens to wood during heat treatment?

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for wood at home

Hello dear readers and subscribers of Andrey Noak's Blog! Do you know what is the most important thing in wood materials? This is a quality dryer. Each enterprise uses a special drying technology. But if you want to dry the material yourself, then I will tell you how a do-it-yourself vacuum dryer is made. But first, some theory.

Wood is a hygroscopic material, this is due to the fact that wood absorbs water vapor from the air. Each wood material has a different degree of humidity, depending on storage conditions and the environment.

Why dry wood?

Drying is the process of removing moisture from a material by evaporation. When a tree grows, the metabolism in it is carried out with the help of moisture circulation through the trunk. When cutting, circulation stops and moisture begins to evaporate. In order to build a house or make any wooden product, you need to dry the logs with high quality.

Purchased vacuum dryer

Well-dried material is protected from fungi, damage and cracks, and the service life will increase markedly.

If the drying was of high quality, then the product will serve you for many years.

Wood is divided into categories depending on the degree of moisture:

1. wet is the one that was in the water and its humidity is one hundred percent;
2. freshly cut, with humidity ranging from 50 to 100%;
3. air-dry, in cases where the material has been exposed to air for a long time. The moisture content of such wood is approximately 15-20%;
4. room-dry, with humidity 8-12%
5. absolutely dry, the humidity of which is equal to 0.

Wet material will be difficult to process, but is flexible and elastic.

Dry wood properties

Dry material has greater biological stability. After drying, the strength increases, it withstands the load better. It is easy to process, and the products do not crack after processing, unlike gray wood, in which the rotting process can even begin under suitable conditions.

Old ways of drying

A long time ago, people used only wood to build houses. In the houses you can find wooden utensils. Therefore, it was necessary to come up with methods for high-quality drying of a log, as the main building material. At that time, people used several methods of drying.

wood evaporation

For this method, the necessary piece of wood, water and sawdust were taken. The water was heated to 70 degrees, the workpiece was placed in it, then covered with sawdust and left for a certain time so that the material was steamed.

After drying, the workpiece did not crack, and the structure became more dense and flexible.

Waxing

Waxing is another method that has been widely used for a very long time. Here, wooden blanks were lowered into paraffin heated to 40 degrees and left for several hours. It was important to maintain the same temperature of the substance.

After the procedure, the wood should dry for several days. The properties of the material change after drying. The workpiece does not crack, does not rot and acquires an original tinted shade.

Masters used this method of drying to make wooden utensils, then the finished product was skillfully painted.

Wood moisture, measurement methods

There are many ways to determine humidity. Special devices are used to accurately determine the moisture content of wood. Electric moisture meters are able to determine humidity with an accuracy of 2-3%. The basic principle of such devices is based on the fact that wood of different moisture content has different electrical resistance.

There are many more "folk" ways to determine humidity, but only professionals use them:

• By weight, weighing the same pieces of wood of the same species in the hand or on the scales alternately.
• Experienced experts determine the moisture "by eye", by the presence of cracks and faults.
• By strand. When processing lumber, small chips are compressed in a fist. If it wrinkles easily, then the material is wet. Dry wood is indicated by the fragility of the chips, but if the chips crumble, then most likely the tree has dried out.
• By cutting. If during the processing of wood with a chisel a wet trace is noted, and the material is easily, smoothly cut, then it is not dried. It is better not to carve on such a surface, as cracks and flaws will appear when it dries.

We assemble a vacuum dryer at home

It is very profitable to dry the wood yourself, and if you do it with a vacuum dryer, the drying time will be reduced significantly. But buying vacuum drying at factories is expensive, and I will tell you how you can make it yourself, and also save on it.

Drying at home takes place in special chambers. To equip it, you will need a large room, a heat source, as well as a fan to distribute heat inside the structure.

Be sure the floor, walls and ceiling of such drying must be very strong, reinforced concrete or an iron conveyor is best suited. If you take a cheaply used iron conveyor, for example, from the railway, then this will even be a very cheap option. Or, for example, to reduce the cost, you can weld the conveyor yourself from old iron.

To preserve heat inside the chamber, we strengthen the walls with foam plastic and trim with clapboard. Instead of foam, you can use mineral wool or other insulation.

To reflect heat, you need to lay a special material. You can use foil, but penofol is also suitable, especially since its heat-reflecting and retaining qualities are much better.

We proceed to the installation of the heating device. The entire heating system must be installed separately from other heating circuits and must constantly work. You can use a heating radiator, with which water is heated to 65-90 degrees. In order for the heat to be equally distributed in the chamber, a fan is required, otherwise there will be uneven drying of the raw materials and, accordingly, poor quality. Another point, the temperature in the chamber should change smoothly and gradually.

When building your own dryer, you must comply with all fire safety rules.

An important point is the construction of a system for loading lumber into the chamber. You will be loading large and fairly heavy boards. For this, carts moving on rails or a forklift are well suited. The material inside is stacked on shelves or just on the floor. To control the drying process, you must install special sensors, and these are thermocouples and vacuum (pressure) sensors. Having done everything right, you can get very high-quality wood with a good presentation.

The main point in the construction of drying is to achieve the necessary parameters inside the chamber, and the materials and equipment that were used do not matter. In your chamber you can reduce the drying process of raw materials up to 2 weeks.

How Vacuum Drying Works

After you have put the material in the drying chamber, tightly closed the door, you can start drying. Air is extracted from the chamber to create a vacuum of about 9 - 10 bar. It is known that when the pressure is reduced, the water boils faster.

Thanks to this technology, bound and free moisture will move uniformly from the center to the periphery, thereby ensuring high-quality and uniform drying of the material, regardless of location.

Dry top wood cells will absorb moisture from those located in the core. First, thin places dry out, then moisture from thicker layers moves to the dried ones, thereby moisturizing them. If this process is interrupted, then the material may be destroyed, since the displacement of thinner layers begins.

Covering the ends of thick lumber to prevent rapid release of moisture and the formation of cracks during drying...

To prevent displacement, lumber is treated with a special mixture, which is made from chalk, as well as drying oil. Often it is necessary to process the end parts of the blanks.

Drying excludes the use of humidification systems, and thermometers should not be installed in the chambers. You can control the process using special sensors, which are controlled from the outside, often in a separate vestibule.

Very often, vacuum plants are used for drying expensive species such as oak, merbau, padauk, wenge, zebrano. It is very convenient, since the wood practically does not collapse during drying.

My help

I have the opportunity to provide advice on drying technology, the selection of new and used equipment. You can contact me through SUPPORT.

Recently, my new book has been published, which gives recommendations on the operation of drying complexes in production. The information that is given in the book is simply unique, you will definitely not find it anywhere else. More information about the book can be found in the "MY BOOKS" section.

Good luck and see you soon!

Video of vacuum dryer

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What is wood heat treatment - features of carrying out

Sections of the article:

Before the direct use of wood in construction, it must first be processed without fail. There are several methods for this. Otherwise, this material may swell under the influence of moisture, which will serve as an excellent environment for the growth of fungi and various other bacteria.

Literally some time later, wood was treated only with chemical compounds. But because of the harmfulness of these funds, their use for such purposes has become prohibited.

What is wood heat treatment?

Thanks to thermal technologies, it is possible to process wood and abandon chemical compositions. After such processing, the properties of wooden elements improve, and, accordingly, their scope expands.

You should know that at the moment the most effective way of heat treatment of wood is the technology of steam stabilization. Such processing is carried out within 12 hours.

During this treatment, the wood is exposed to steam within a temperature range of 220 degrees. Thus, the structure of the wood changes. In this case, no chemical additives are used.

What are the characteristics of thermal wood?

Wooden elements under the influence of such steam treatment improve the following qualities:

Moisture resistance. As a result, the ability to absorb water is reduced by about five times;

stable value. When changes in humidity and temperature are observed, this indicator improves tenfold or more when compared with untreated wood;

Excellent resistance to biological damage. Due to the fact that wood is processed under the influence of high temperatures, polysaccharides decompose inside the material.

After all, they are an excellent breeding ground for bacteria and microorganisms. As a result, the operational period of wood increases by almost 25 times.

Scope of thermowood

Heat-treated wood is used in the manufacture of doors. Such structures are not deformed during use. Although their price is almost the same as that of chipboard products. Still, their design and quality indicators are top notch.

Also, steam-treated wood is used in the production of eurowindows. Windows made of this material easily tolerate direct contact with moisture.

Parquet made from thermowood is much easier to install. Ugly gaps will not remain between the elements, and the floor itself will last the maximum possible amount of time.

Do-it-yourself wood aging: types and methods of processing

Many design styles (French, Tuscan, vintage, shabby chic and others) are characterized by the presence of antique woodwork among their elements. Paint wear, the texture of old wood give a special charm to the interiors. In their work, designers actively use antique furniture, wall panels, floors, stairs, beams, columns and other small decor. However, antiques are not cheap, which greatly inflates the cost of projects, and wooden elements from the past are not strong and durable. To solve these problems, artificial aging of the tree has appeared, and you can even do it yourself.

Aging methods

There are several ways to age a wooden surface. The choice of the desired aging method is influenced by the type of wood, the design style, the availability of the necessary tools and materials, professional skills and experience. The following types of artificial aging of natural wood are most common:

• chemical way;
• heat treatment;
• brushing;
• wood aging by dry brushing.

chemical method

In order to process wooden products by this method, it is necessary to have special chemical reagents, professional tools, certain qualifications and knowledge. Caustic substances (acids, alkalis or copper sulphate) are applied to the surface of the parts, after which the wood changes color, and the soft fibers are destroyed. The process itself is hazardous to health and requires increased security measures. It is almost impossible to implement such artificial aging with your own hands and at home.

Heat treatment method

The essence of this technological process is to burn less dense layers of wood by means of an open fire. It consists of several stages:

• annealing soft fibers to obtain the desired wood texture;
• surface cleaning with abrasive materials;
• applying varnish.

To implement this method with your own hands, you can use a very affordable tool - an ordinary blowtorch.

brushing

The name of this technique comes from the English word "brush", which means a brush. Brushing is based on the structural features of wood, consisting of hard and soft fibers, and the process itself consists in combing soft fibers out of wood with a metal brush and giving the surface the texture of old wood. Do-it-yourself brushing can be divided into a number of successive stages:

• mechanical processing of wood along the fibers;
• cleaning from chips and pile;
• glossing;
• staining or patination;
• varnish coating.

Despite the fact that the tool for brushing seems extremely simple, the process itself is quite laborious. When using this method of applying a touch of antiquity to wooden products, it should be remembered that hardwoods, as well as pine, yew and larch, cannot be brushed.

Artificial aging of wood by dry brushing

This process is also easy to do with your own hands, it is applicable to cabinets, tables, shelves, armchairs and other types of home furniture. It consists of several stages, and not all of them are required.

1. Creating the effect of many years of operation.

At this stage, scratches, potholes, chips and dents are applied to the surface of the furniture. To do this, you need a carpentry tool and a little imagination. Since the damage caused is irreversible, this stage of tree aging can be skipped.

1. Coloring.

For this, two variants of paint of similar shades are used. First, one is applied, and after drying - the second.

1. Surface treatment with abrasive materials or sanding.

Using fine sandpaper or sand, the top layer of paint is erased. This is done unevenly, in some places only up to the first layer, and in some places up to wood. It is important to achieve the effect of natural wear, so special attention should be paid to the edges and protruding parts. After sanding with a vacuum cleaner, chips and wood dust are removed.

1. Applying paint with a dry brush.

At this stage, it is important to choose the right tool for applying paint. A stiff, flat brush works best. The choice of paint should also be approached responsibly. It should be contrasting with previously used shades. For a light base, the best option would be dark shades of brown or burgundy paint. The technology of applying paint to the surface in this method of wood aging is the most complex. The paint is applied with your own hands with an almost dry brush, the strokes should look like a trace of numerous bristles. Crossing strokes is not allowed.

1. Rubbing the top layer.

For this, a cloth napkin is used, which smears the newly applied strokes.

1. Coating the surface with varnish.

It is best to use a clear varnish, which should be applied in one or two coats.

There are several more ways to force the aging of wood with your own hands, but they are not so effective and do not always achieve the desired goal.

During construction or finishing works, the favorite material was and still is wood. But in order for wooden materials to serve for a long time, not to rot, not to swell and not to dry out, they have to be pre-treated with various chemicals.

But not everyone wants to deal with chemistry, so now heat-treated wood has become widely used.

Many people wonder what is heat-treated wood? These are wooden products that have undergone heat treatment at high temperatures without the addition of chemicals.

Thanks to this processing, the tree receives many positive qualities:

Technology of heat treatment of wood

This technology was invented by Finnish specialists.

It consists of several stages of processing:

• - first, the wood is dried by placing it in a drying chamber for a long time at a temperature of 100-300 degrees. At this stage of processing, all moisture is removed from the wood;
• - heat treatment - for such treatment, hot steam is launched into the chamber where the wood is located, the temperature there is above 250 degrees.

IMPORTANT! Heat treatment takes about 3 hours. At the end, the heat-treated wood is cooled, reducing the temperature in the chamber, the moisture content of the product is 4-6%.

Heat treatment is different:

1. - single-stage;
2. - multi-stage - with this treatment, steam is supplied under a certain pressure.

IMPORTANT! For the production of thermowood of the highest quality, not air vapor is supplied under pressure, but nitrogen (rectification is done). Wood can differ in appearance, shade and its properties if treated with different steam temperatures, therefore, its price will be different.

Therefore, it is divided into classes:

• - first class - steam treatment up to 190 ° C, the shade changes slightly, the properties are improved to a minimum;
• - the second class - steam treatment up to 210 ° C, the shade is darker, the strength of the wood increases, and the resistance to the decay process also becomes higher;
• - third class - steam treatment up to 240 ° C, the wood has rich dark shades, here all properties are increased to the maximum (strength, stability, density).

IMPORTANT! Before you buy thermowood, specify what class it is, and decide what shade you need it for construction.

How to make heat treated wood at home?

It is not difficult to buy heat-treated wood, for example, buy it in St. Petersburg or buy it in Moscow, it is now sold everywhere. But usually only in specialized stores. Only the cost for it is much higher than for an ordinary tree. Therefore, many craftsmen often ask this question - how can you make such wood with your own hands at home?

With a strong desire to do this, it is possible. Only the process of manufacturing thermowood is very laborious, but the result is worth it.

To make a thermal chamber, we need the following elements:

A container with water is placed in the thermowood chamber in order for the water to evaporate due to the high temperature. This will prevent the wood from burning. To maintain a high temperature, the chamber must be well heated.

IMPORTANT! The chamber must be hermetically sealed, because if oxygen gets in there, there will be a risk of wood fire.

This option is suitable if you need to process large wooden products. For processing small pieces of wood, there is another way how to do it yourself. Take a tree, boil it for 1.5 hours, then wrap it in rags or paper and dry these wooden products near a stove, battery or heater.

Use of heat treated wood

Due to its positive qualities, thermowood is a versatile material. It can be used in the construction of a garden gazebo,. It looks great as an external finishing material for the facade of the house, it can also serve as a floor covering.

Facade thermowood- presented in the form , . The beautiful appearance of such products lasts a long time, does not require strong care.

In damp rooms (, ) we can also often find the use of a thermal board. It does not get very hot and is not afraid of moisture.

Although heat-treated wood has many advantages, there is also a drawback - under the influence of sunlight, the surface burns out over time and the shade becomes gray. But only the topmost layer is damaged, inside it remains strong. In order to prevent burnout, you can additionally treat the thermowood with oil products. After that, such wood will serve you for a long time, and please the eye with its beautiful appearance.

Another drawback is, of course, the cost of such wood, but we have described to you the opportunity to make it yourself, which will be much more profitable.