Firing wood with a burner: choosing wood and following technology

Wooden buildings without additional protection cannot boast of significant durability. Traces of rotting can appear on them quite quickly, so it is necessary to use various technologies against the development of mold and microbes. Many of them are not environmentally friendly, and such wood is used only outdoors. Burning wood is an absolutely safe method that was invented many years ago. It allows you to preserve the natural qualities of the material for a long time and give it an unusual appearance.

What is it needed for?

Of course, the easiest way is to go to the construction market, buy varnish and coat a wooden product with it.
But the chemical composition of the varnish constantly releases fumes into the environment, albeit small, but harmful to human health. This is facilitated by temperature exposure, sunlight and even the operation of heating radiators. Finally, not all materials are easy to process; a different approach is required. This is where wood burning comes to the rescue. It works like this: during heating, which is constantly under the control of the master, processes begin in the outer wood layer that stimulate the narrowing of the fibers. And the outer pores are closed by soot and resin.

This decorative method of changing the characteristics of wood is not very complicated. And although you have to deal with fire, the technique itself is elementary. Usually gas burners are used for firing. There should be safety equipment nearby: a fire extinguisher and a bucket of sand. In ancient times, craftsmen made do with torches, and the log was gradually turned over on leather ties. This could be called either firing or simmering. Cedar, ash, beech and maple were taken more often than other species.

It is very important that the material itself does not burn during the firing process, but rather becomes scorched. This added special beauty to it and protected it from moisture and decay, and pathogenic organisms. After firing, it was necessary to remove the deposits, wash the workpieces and soak them in oil

In addition to protection, the tree acquired a special shade. Today, in this way, wooden products are given an “antique” effect. The service life of such a product increases significantly

After firing, it was necessary to remove the carbon deposits, wash the workpieces and soak them in oil. In addition to protection, the tree acquired a special shade. Today, in this way, wooden products are given an “antique” effect. The service life of such a product increases significantly.

Decorative possibilities of burnt wood

After firing, wooden surfaces radically change their appearance. The light areas darken, and the resinous annual layers become almost black. This shows the difference between firing and the use of water stain - it makes the annual rings remain light, but it is the spaces between them that darken. The wood pattern becomes pronounced, and some flaws are either hidden or become expressive decorative elements.

Experienced craftsmen select boards so that all knots or expressive elements of texture are located evenly over the entire surface of the wood - this allows them to obtain a more harmonious and attractive product.

The most effective result can be obtained if, after firing, the top, most burnt layer of wood is removed.
The best option is to use a planer or thicknesser. A small layer is removed - about 1 mm (the depth of planing depends on the intensity of firing, this procedure requires skill and is regulated experimentally). After planing, the surface becomes somewhat lighter, and the wood pattern begins to look more natural. This processing option is best suited for preparing wood for furniture making. The main advantage of this processing method is its extremely low cost - the entire process costs only the price of the material and the cost of the gas consumed.

Charcoal firing in the field

The simplest method of fire treatment is best suited for deep firing. Decorative beams are treated in this way, as well as wooden siding and block houses for exterior decoration. Due to deep heating, the wood becomes impervious to atmospheric influences, and the influence of sunlight does not affect it at all.

For charcoal firing, dig a narrow trench about 30 cm deep and a width corresponding to the size of the parts being processed. A fire is built in a ditch, and as it burns, the wood is constantly stirred, achieving rapid charring. After this, the ditch must be covered with either sheet iron or a strip of OSB to temporarily prevent the access of oxygen and stop the combustion.

Before laying the workpiece in the coals, you need to rake out the central furrow so that during firing, not only the lower part, but also small areas on the sides are processed. The holding time of the workpiece depends on the thickness and can range from two to three to fifteen minutes. After this, the workpiece is turned over to the opposite side, and then, after maintaining the same period of time, it is burned on the sides.

It will be easier to remove the workpiece with a pair of steel wire hooks. After the wood is removed from the coals, it is immediately doused with water.

Advantages and disadvantages

Firing is often used in construction and other fields. In addition to giving a special texture to the wood, this method is good for other reasons.

Obvious advantages of burning wood:

• You don’t have to use complex chemicals – everything will be natural;
• if you follow the technology, the method is not complicated, and a special firing workshop is not required;
• the material becomes fire-resistant, wear-resistant, and ceases to be vulnerable to microorganisms.

High temperatures cause hemicellulose formations in wood to decompose under their influence. When burned, they form pyrolysis gases, the main feature of which is easy ignition. That is, the tree will become resistant to fire. It turns out that the fire problem is solved using the “wedge by wedge” method.

There is only one significant disadvantage - the process is labor-intensive.

Interior use

Burnt wood is used by designers everywhere. Art workshops and various studios allow you to purchase interesting furniture, a chandelier or a lamp made of wood. Options for using burnt boards in the interior.

Furniture can be made from smooth, processed boards or rough-hewn beams. In any case, it is highly appreciated. Sometimes it is not even used for its intended purpose, but is used only as a decorative element.

The floor covering after firing requires leveling. For this, simple epoxy resin is used. She does an excellent job and does not require any special skills to work.

Deep firing

This process is carried out in open furnaces. In this case, the burning depth of the top layer should not exceed two centimeters. This method is used for processing used wood. The surface subjected to this firing method acquires a refined appearance. The wood takes on a hue that can vary from graphite to deep black. Thanks to this feature, imitation of valuable species is possible.

It is impossible to obtain this color of wood using other methods. Therefore, material processed using deep firing is especially valued by designers.

What types of wood are best suited for fire processing?

It is believed that any wood is suitable for firing. However, for those who want to get a unique visual effect, experts recommend using only certain breeds. It is noteworthy that initially only cedar was used in traditional Japanese technology. Later they began to treat beech and hornbeam with fire. When burned, such wood acquired a gray color that shimmered beautifully in the light. This effect can be achieved by burning the top layer of wood.

Today, species such as maple, alder, and poplar are especially popular in firing. If you need to get a surface with a fine texture, then in such cases larch and walnut are used.

When building baths, only birch is used. When exposed to fire, this type of wood becomes porous and acquires a low heat capacity. Thanks to this, when exposed to temperatures, it cannot burn the skin.

An interesting fact is that the same wood can appear in different ways. It directly depends on the firing method

But in any case, it is important to properly prepare the material for processing.

Wood for firing should have little moisture. The maximum acceptable is 13%. In addition, the material should not have traces of paint and varnish coatings. It must be completely cleaned

In this case, this is important, because resinous substances absorbed into the wood will appear unevenly on its surface during firing. This will significantly spoil its appearance.

What kind of wood should it be?

Initially, coniferous trees such as pine or cedar, larch, and spruce were used for firing. These types of wood have a fairly soft structure and are easy to process. After the firing process, such wood produces quite beautiful and original patterns, without stains.

Nowadays several other types of wood are often used, which also lend themselves well to firing. When fired on maple or poplar wood, beautiful elongated lines are formed along all the grains.

Also, to process wood with this process, you can use wood of different qualities; material with knots is allowed. It is worth noting that if there are soft fibers on the surface of the wood, then when fired, small depressions form on the material.

If the wood had a rigid structure, then during firing the wood will become more prominent and after finishing cleaning it will have a fairly expressive texture.

How does firing affect wood?

The structure of wood fibers is always uneven: in the process of life, cellulose polymers of varying degrees of stability, as well as sugars and resins of all kinds, are formed in wood. It is the presence of pores and organic nutrient residues that cause the main disadvantages of wood: flammability and the presence of a nutrient medium for the development of bacteria and fungi.

The opportunity to “seal” wood from the influences of the outside world still exists. It is used during creosote boiling of wood or during autoclave heating (thermolysis). When heated to 300–400 °C, almost all unstable hemicellulose formations are destroyed, and they serve as both a “launching pad” for the ignition of wood (forming the primary volume of flammable pyrolysis gases) and the initial breeding ground for the development of colonies of harmful organisms.

It is incredibly difficult to reproduce such wood processing at home. But it is quite possible to partially clog the internal pores and remove most of the unstable cellulose polymers. Even surface firing can heat the outer layer (5–20 mm) of wood enough to melt lignin and resins and form an inorganic crust that protects against most external influences. After proper firing, wood is almost impossible to re-ignite without intense and prolonged heating to 500–700 °C. In this case, the residual heat kills microorganisms remaining in the thickness of the wood, and the sintered outer layer prevents the penetration of pathogenic organic matter from the outside.

Advantages and disadvantages

Burnt wood changes due to special processing. It can give a special charm to the room in which it is used.

Main advantages and special properties.

1. Firing the material can be done at home, on your own. It is not necessary to involve experts. It’s enough just to familiarize yourself with the technology, prepare materials and tools. Of course, training will be required. However, it is possible to create unique raw materials with a special design.
2. Material with this treatment is fireproof. If you additionally use appropriate impregnations, the risk of fire is completely eliminated.
3. During firing, the cellulose components are destroyed. They are a favorable environment for the development of various pathogenic microorganisms. Burnt wood is not susceptible to mold, insects and other pests.
4. An increase in gyroscopic properties is also a big advantage.
5. As a result of firing, the service life of the material increases. Additional impregnations and coatings make it the best for construction and furniture making. Not only its wear resistance improves, but also its strength.
6. The material, after processing, retains heat much better if used for construction.
7. Original appearance and unusual texture. The unique decorative properties of the material allow it to be used for any purpose.

The only drawback is that burning wood is quite a labor-intensive task.

However, all careful work is rewarded. As a result, the master receives a special texture and unique appearance. If you order ready-made burnt boards, then this drawback will not manifest itself at all.

What will you need?

On an industrial scale, large volumes of wood are fired in vacuum kilns. Layers of wood up to 20 mm thick can burn. It’s difficult to achieve this effect at home, but other, more modest results are also impressive. And the main thing is that they can be achieved using more accessible tools.

The source of flame for firing can be:

• high power blowtorch;
• gas-burner;
• construction hair dryer;
• gas cylinder with nozzle, etc.

You will also need a tool that will clean off the burnt layers. If you have to burn small boards, the amount of work is not very significant, you can get by with a simple metal brush. But it’s convenient to tackle massive structures, such as furniture, stairs, floors, and even buildings, using a grinding machine, a grinder saw, or even a drill with an attachment.

You will also have to sweep away the remains of the burnt material, and a flute brush or soft-bristle brush does a good job of this. Naturally, all work must be carried out in compliance with all safety measures. It is imperative to protect your eyes, clothes and hands so that sparks and fumes do not threaten them. A bucket of sand, water, and a fire extinguisher should be within easy reach.

Is it possible to fire a damp board?

Raw

is also quite
possible to burn
. However, it should be borne in mind that such treatment will partially clog the pores of the material, and the moisture remaining inside will take much longer to come out, which is not good.

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Design

The Japanese art of wood decoration is very popular. In essence, this is an artistic material from which a lot of interior items and finishing elements can be made. The result depends on the type of firing and the material used. As a result of a combination of a number of factors, the board acquires a certain color and texture. Types of firing.

Surface. This type of processing is used more often than others due to its simplicity. This type of firing will require a minimum of experience, skills and free time. You can use a gas torch or soldering iron if the process is carried out at home. Processing is carried out to a depth of no more than 5 mm

It is important to carefully go over all parts of the board to achieve the perfect result. Firing should be uniform over the entire area

Texture

With light exposure to fire, the wood acquires a weakly expressed texture, and with full exposure, an interesting pattern appears, which consists of interlacing wood fibers. Each type of tree shows itself uniquely. Dense material will have the most pronounced grooves. Soft wood will give a sparser pattern.

The floorboard is usually fired superficially and additionally leveled. Decorative items, benches and other furniture are made from material with any texture.

Color

Deep firing makes the wood blue-black, it literally resembles the shade of coal. If the treatment is superficial, the natural color remains virtually unchanged. The material can have any shade in the beige-brown palette.

Some types of wood are more interesting. For example, when hornbeam and beech are fired, a gray and anthracite tint appears. Also, the board or beam can be painted on top in any color. It is worth noting that during processing the natural color is usually preserved. So, burnt wood can be either gray, light, or black, dark brown.

DIY wood heat treatment

Using none of the technologies used, it is impossible to obtain thermally modified timber or logs of low cost in a short time.

Several years ago, thermal timber began to be produced in our country. Wooden house-building enterprises became interested in this material. Considering 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 produce them in their own production facilities.

If a company is engaged in the production of house kits from profiled timber, then additional space will be needed to install the camera, and the machines that are available in the production for processing profiled timber can also be used for processing thermally modified material. There are no restrictions.

The production of a new type of product - thermal timber - allows you to expand the range of products produced by the enterprise and does not create difficulties in work. In their price segment, thermally-treated timber or logs will compete with laminated timber, and in the construction of wooden houses from profiled timber they will replace the latter.

How to burn wood with a gas torch

Using gas burners is much easier. These can be either hand-held camping lamps or regular nozzles connected to the cylinder via a hose.

It is convenient to process wood with gas only by surface firing. Deeper aging in the fire will not be sufficiently uniform, as a result the product may have variable thickness and width. In addition, deep heating will require quite a lot of gas, while coals cost almost nothing.

When surface processing the wood, the very edge of the light blue torch is touched. The movements are roughly the same as when painting. At the same time, it is quite easy to control the firing depth based on the degree of darkening.

Firing is followed by wetting, but in this case an ordinary hand sprayer will suffice

It is important that the time interval between fire treatment and water spraying is the same for all areas of each part, so carry out the treatment sequentially.

Thermowood for construction in the garden and country house

Heat-treated wood can easily replace species used for outdoor construction.

Essential requirements for materials for the manufacture of structures exposed to weathering: they must be resistant to rotting, damage by insects and the influence of destructive factors (sun, rain, etc.), durable and stable.

And to these conditions it would be nice to add beauty and environmental friendliness. Are you saying that this doesn’t happen?

We invite you to get acquainted with thermally modified wood. This ideal material may be more affordable than you think.

Thermowood technology: not just drying

Thermal treatment of wood is not something new; it has been used since prehistoric times. Primitive hunters burned the end of a wooden spear with a fire to make it harder. But only in 1990

Scandinavian timber industry decided to take a closer look at the process in the laboratory.

As a result of these studies, a technology has emerged that has been used in European countries for two decades and has begun to conquer North America, where thermowood production volumes are increasing annually.

The thermal modification process begins immediately after drying the boards in a chamber where the material is heated to a temperature of 260°C. The sugary substances contained in wood sinter, becoming an unsuitable environment for insects and microorganisms that destroy wood. The cell walls that form wood fibers, which usually easily absorb moisture and dry out, stop swelling after heat treatment.

Decorative value of burnt wood

Much more interesting is the visual effect of burning wood. It was thanks to him that the technology of processing wooden beams under the whimsical name “Shu-Sugi-Ban” was born in Japan, and the meticulousness of the Japanese to the interior design of homes is well known to everyone.

The appearance of wood processed in this way directly depends on the technique and depth of firing, and there are three types. The first - surface firing - allows you to create a brown-brown surface with a golden sheen, on which the wood texture appears quite contrastingly. The chemical and biological resistance of such wood is not high enough, so surface-fired products are used, as a rule, in interior decoration. Due to the fact that the impact on the structure of the wood is minimal, since firing affects only 2–5 mm below the surface, finishing materials can retain their lightness, that is, it is quite possible to process ordinary lining in this way.

Deep firing of wood is used for older lumber, often for boards and beams that have already been in use. This technique helps to “renew” the wood: remove the dried out surface gray layer and efficiently heat the entire thickness of the wood. Due to this, the surface acquires a very expressive appearance: from iridescent graphite to coal-black imitation of rare noble rocks. Perhaps, such a depth of black color cannot be achieved by other methods, which is why deep-fired wood is so highly valued by designers.

The third stage of wood processing is its complete burning. Actually, it ceases to be a tree at all, turning, in fact, into polymer-carbon plastic. At home, unfortunately, complete firing is almost impossible: during charring, the fire will have time to eat almost half the thickness of the workpiece. This wood is used primarily in the production of furniture. The technique guarantees the absolute uniqueness of each product, because the characteristic pattern and the resulting splits cannot be reproduced in any way.

Application area

Thermowood is used wherever ordinary wood is used. This is a very expensive material and you just need to make the right decision about the advisability of its use. For example, it is cheaper to finish the walls and floors inside a building with ordinary wood. Such expensive material is used where it justifies its costs:

• For finishing the facade, linings with grooves for installation, simple planks, and block houses are made. The properties of the material allow the original appearance of the house facade to be preserved for a long time. In addition to aesthetics, bark beetles and fungus will not appear in the façade;
• Thermowood garden parquet looks beautiful on your home plot. It won't be difficult to install it yourself. The planks are easily connected with locks. They are used to lay garden paths, bathroom floors, pool areas, sauna floors, and terraces. In general, garden parquet made of thermowood will last a long time in any damp room and outdoors. Protective oil helps extend the life of parquet;
• Wallpaper made from thermowood has all the advantages of natural wood.
  They are moisture resistant and can be used in rooms with high humidity, such as a bathroom; Wood wallpaper
• In all damp places in the country house, a thermowood terrace board would be a good flooring material. It differs from deck boards by its corrugated surface. Installing the board on the floor is easy to do yourself in a gazebo, open veranda, terrace;
• The deck board has a smooth surface. The material has nothing to do with a sea vessel. It only imitates the smooth surface of the deck. Another difference between deck boards is rounded chamfers. The scope of application of deck boards is the same as that of terrace boards. Basically, its installation is necessary for arranging the floor. To ensure that the deck board is not slippery, after the installation of the floor is completed, it is coated with anti-slip oil;
• thermowood is used for the manufacture of decorative elements: window sills, handrails, trim and other elements. The window sills installed in the bathhouse are resistant to moisture and never deform. An oiled window sill will retain its color for a long time under any conditions. Flower growers always place their plants on the windowsill and careless watering often spoils them. On a window sill made using heat treatment, watering flowers will not spoil the texture. Thermal boards make beautiful garden furniture;
• Timber made using heat treatment is widely used in construction. Houses and bathhouses are built from timber. SHP timber is used in the construction of terraces, gazebos, and fences. To decorate the interior, timber is used in garden design and wall decoration. The timber is used for installation of rafters, supports, joists under deck and terrace boards. It’s easy to make a strong support in an outbuilding yourself from timber;
• The thermal board, unlike a regular board, can withstand temperature changes well. Therefore, it is more suitable for arranging a heated bathroom floor. The main thing for the floor is to use uniform electric heating to a temperature of 35°C. Warm floors in the bathroom made from thermal boards will create an unusual design.

Bathroom finished with thermowood

What to process?

In principle, the material can be left in the same form, without changing anything, without resorting to any impregnation. But many craftsmen are sure that it won’t be superfluous to varnish and soak beautiful, renewed wood. Especially considering that this will increase the level of security of the material.

Oil better emphasizes the decorative characteristics of wood. And it will be used in this form even longer. And then you can also apply varnish on top of this treated surface, preferably nitrocellulose. A mixture of varnish and artificial wax is also suitable. But if it is the façade wood that needs to be treated, a turpentine-wax solution would be an excellent composition.

The best way to impregnate burnt wood is oil. Tung, flax and hemp are ideal options. It is more convenient to apply the liquid with a brush, although a spray gun will do. And this is the most environmentally friendly processing option (in combination with firing).

Tinted synthetic oil compounds are also used; they can visually transform simple wood types into noble ones. They very favorably accentuate the structure of the wood and protect it from external aggressive influences.

The most beautiful boxes, large wall panels, and baguettes are made from the fired material. It can also be used to make extravagant tables, chairs, solid chests of drawers and cabinets. Decorating walls with such textured wood is also attractive, especially in interior styles that are conducive to this - from chalets to lofts.

To learn how to burn wood with your own hands, watch the following video.

Advantages and disadvantages of burning lumber

The main advantage of the technique is that it does not require the application of impregnations or antiseptics, which are sometimes not environmentally friendly and may even contain toxic components. Other benefits of wood burning:

• possibility of doing it yourself,
• no need for special skills, expensive tools,
• protection of the material from wind, moisture, mold, germs, insects, ultraviolet radiation,
• efficiency,
• making it fireproof (re-ignition is almost impossible),
• reliable prevention of rotting,
• ensuring wear resistance, increasing service life.

The only disadvantages include the laboriousness of the process, which is carried out without the presence of industrial equipment, because you will have to manually burn each board, then clean and process it. However, the unique texture, original appearance and unique technical characteristics of burnt wood eliminate all possible disadvantages and increase the popularity of the technology.

Finishing of burnt wood

After the wood has cooled, soot and soot are removed from it. For this purpose, brushes made of brass wire are used so as not to strip off excess. During mechanical processing, texturing or so-called artificial aging of wood can also be carried out.

Cleaned products can be installed immediately. Additional processing is needed not so much to protect the structure of the wood, but to preserve its color and overall appearance after years, as well as to eliminate soiling. For interior decoration, the lining is coated with linseed or hemp oil in several layers. Wood for facades and other external works is coated 1–2 times with colorless nitrocellulose varnish with the addition of synthetic wax: either with a brush along the grain or with a spray gun.

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Surface firing

This method is the most popular. Its essence lies in uniform burning of wood with a gas burner. In this case, only the top layer, the thickness of which does not exceed 5 millimeters, is processed. The popularity of this method is due to several factors. First of all, this is the availability of the burners necessary for firing wood and the simplicity of the procedure itself. It is noteworthy that the material processed in this way acquires increased strength and an unusual texture. Wood subjected to surface firing is used both for interior decoration and for exterior work.

What species and what type of wood is best to burn?

Generally any wood is suitable for firing, but connoisseurs of subtle visual delights will most like species with an expressive and unusual texture. The original technology of Japanese origin initially used exclusively cedar. Burnt hornbeam and beech boards have an interesting appearance: due to the high density of such wood, only its top layer burns through, resulting in anthracite and gray tints of color.

More popular valuable species, such as alder, maple and poplar, exhibit an elongated texture after firing, while walnut or larch can form additional finer textured patterns. Burnt birch will be highly appreciated by bath or sauna lovers: due to firing, its surface becomes very porous and acquires a low heat capacity, so after heating it does not burn the skin.

It is also surprising that, depending on the degree of firing and the origin of the wood, even the same species can manifest itself in completely different ways. When using burnt wood in decorative finishing, you should take a thorough approach: stock up on samples of different types from different sources and, after a series of experiments, come to a certain choice.

Remember also that the wood must be properly prepared before firing. It should have low humidity, preferably no more than 12–13%, and also be natural, that is, without traces of painting or opening with drying oil. Otherwise, the absorbed resinous substances will appear unevenly on the surface and disrupt the appearance. Of course, a lot here depends on the depth and time of fire treatment.

Thermowood painting and surface treatment

It is painted in the same way as regular wood. Low resin content prevents defects on painted surfaces due to resin release. Surface treatment of thermowood must be carried out strictly according to the instructions of the manufacturers of the applied compositions and mixtures. Paint and other compounds are best applied to the smooth surface of planed material with a brush. Oil compositions are applied in the same way as on ordinary wood. And when applying aqueous solutions, you need to remember that the material does not absorb moisture well. Paint and varnish compositions that dry under ultraviolet light are perfectly applied.

Structural changes in wood during firing

The structure of wood is such that when layers are built up under the bark, some kind of pores appear in it. As a result, the fibrous cells die. Thanks to high porosity and displacement of fibers, wood acquires its main and most valuable feature - excellent hygroscopicity. Thanks to this quality, it is able to give and absorb water depending on the difference in the humidity of the environment and its own.

The second no less significant feature is the unevenness of the structure. This is due to the formation of cellulose polymers, resins and sugars during the life of the tree. Such substances are the main organic components of the plant. They also cause the main disadvantages of wood - flammability and the formation of a favorable environment for fungi and pests.

In order to reduce the tree's exposure to external influences, several protection methods are used. First of all, this is autoclave heating and creosote cooking of wood. During the procedure, the material is exposed to high temperatures, due to which hemicellulose formations are destroyed. They are the main cause of wood fires. It is almost impossible to carry out such an operation at home. But there are a number of other more accessible methods for partially blocking pores and removing polymers. One of them is burning wood with fire.

Many people do not understand why wood should be subjected to such processing. Experts know that firing helps narrow the fiber channels of wood. In addition, they become clogged with resins and combustion products. Thanks to this, the service life of wood is extended for decades.

Furniture and interior items

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Despite the fact that we live in an age of innovative technologies, wooden housing does not lose its relevance, continuing to conquer new horizons. The popularity of wooden buildings is due to the unique properties of wood, namely its environmental safety and high wear resistance. However, due to the peculiarities of its structure, wood needs proper protection, which will extend the service life of the material while maintaining its original characteristics. Currently, for wood processing, it is customary to use chemicals that have antiseptic and antifungal characteristics and prevent damage to lumber by insects, mold and other microorganisms, and also reduce the flammability of wood. Recently, supporters of environmentally friendly materials have begun to pay attention to another method of wood processing - roasting. Despite the fact that it is generally considered innovative, and burnt wood is a novelty in the field of finishing materials, the first mention of the use of this method dates back to the 18th century. It was then that the Japanese first told the world about the unique technology of uniform processing of wood Shou Sugi Ban, which translated into Russian means “languishing cedar.” As you know, everything new is well-forgotten old, and today charred wood is again at the peak of popularity. What are the advantages of burnt wood and how to burn wood at home – we’ll look at it in this article.

Content

1. Wood burning technology: historical background
2. Structural changes in wood under the influence of firing
3. Benefits of charred wood
4. What is the firing procedure: types of firing
5. How to burn wood at home: a step-by-step guide
   How to choose the right type of wood?
6. How to prepare material for firing?
7. How to burn wood with a blowtorch?
8. How to burn wood with a gas torch?
9. Burnt wood in the interior

Wood burning technology: historical background

Despite the fact that domestic craftsmen recently paid attention to charred wood, in developed countries it has long been at the peak of popularity. For example, on the island of Naosami (Japan), burnt wood is widely used as a building material, and in the interior decoration of the home, burnt wood products are certainly used, for the manufacture of which the ancient Japanese technique of “simmering cedar” Shou Sugi Ban was used. Processing wood in accordance with this technique allows not only to make the texture of the material more distinct, but also to protect it from insects, rotting, and fire. The history of this method of protecting wood began in the 18th century, when the Japanese, thinking about fire protection of the territory, began to burn stands of Japanese cypress (also called Japanese cedar) growing around Japanese villages. Later they noticed that the burnt cypress wood not only did not lose its original properties, but also acquired additional decorative and performance qualities, becoming resistant to fungus and insects. This was the starting point for the widespread use of burnt wood for cladding facades.

Despite the fact that Japan is considered the birthplace of burnt wood, this method of processing lumber has been known on almost all continents since ancient times, when, along with tarring (impregnation of wood with hot resin), it was used as one of the most effective ways to protect wood from insects and rotting . This is due to the structural characteristics of the tree, which undergo some changes under the influence of open fire. Let's look at them in more detail.

Structural changes in wood under the influence of firing

The structure of wood is such that as the subcortical layers grow, pores form in it, which leads to the gradual death of fibrous cells. The increased porosity of the structure and the gradual displacement of fibers determine one of the most important performance qualities of wood - its high hygroscopicity, that is, the ability to release and absorb water particles depending on the difference between its own humidity and the humidity of the environment.

Another feature of wood is the unevenness of its structure. It is caused by the formation of cellulose polymers, sugars and resins during the life of wood, which are its main organic components and cause the main disadvantages of wood - flammability and the presence of a favorable environment for the proliferation of fungi and bacteria.

However, there are quite effective ways to reduce the exposure of wood to external influences. These include autoclave heating (thermolysis) and creosote boiling of wood, during which lumber is exposed to high temperatures (up to 300-400 degrees), which contribute to the destruction of unstable hemicellulose formations. They are the cause of the formation of highly flammable pyrolysis gases and, as a consequence, fire. It is almost impossible to carry out such treatment at home, however, there are other, more affordable ways to partially block pores and remove most unstable polymer formations. These include wood burning.

Why burn wood and how will this affect its performance? During the firing process, the fiber channels of wood become narrowed, as well as become clogged with resins and combustion products, which helps extend its service life.

In Rus', in order to burn wood, it was often simply thrown into a fire, which became a kind of prototype of the modern firing procedure. Often, only the lower part of the pillars, which were installed in the pits during the construction process, was fired, as well as joists and boards for the floor and roof. This phenomenon in Rus' was called “smoking.”

Benefits of charred wood

• Burnt wood can be made independently at home. To do this, it is not necessary to involve specialists; it is enough to familiarize yourself with the basic principles of firing and prepare the appropriate tools;
• Material prepared in this way acquires a high degree of fire safety, since re-ignition of wood is practically impossible;
• Due to the fact that in the process of burning wood, the destruction of cellulose components, which are a favorable breeding ground for bacteria and fungal microorganisms, occurs, its damage by insects, mold and bacterial microorganisms is practically eliminated;
• Burnt wood is characterized by a high degree of hygroscopicity.

Burnt wood photo

What is the firing procedure: types of firing

The appearance and decorative value of burnt wood may vary and directly depend on the firing technique and depth. Depending on the depth of firing, there are three degrees of wood processing:

• Full firing is a type of heat treatment of wood, which makes sense to talk about if we are talking about large-scale work. Complete burning of wood is carried out in vacuum furnaces at temperatures up to 400 degrees. Wood that has undergone a full firing procedure is used extremely rarely, since, despite its initially high strength, it not only decreases in size by almost half, but also loses its performance characteristics. However, this technique has found its application in the manufacture of furniture from burnt wood;
• Deep firing is a technology more often used for previously used lumber. Having subjected the boards and beams to deep firing, you will notice that the entire thickness of the material has warmed up qualitatively, and its surface has acquired a more expressive appearance - the shade of such wood ranges from iridescent graphite to coal-black, making it possible to imitate valuable species. Such a deep black color is almost impossible to achieve by treating wood with other methods, due to which the value of the material has increased significantly in the eyes of modern designers. Deep burning of wood is carried out in open kilns, and the permissible depth of burning of the top layer of material can reach 20 mm;
• Surface firing is the most popular method of heat treatment of wood in home and industrial conditions, the essence of which is to uniformly burn the material using a blowtorch or gas torch, burning the top layer up to 5 mm. Wood that has undergone the firing procedure is sanded, as a result of which it acquires not only its original texture, but also increased strength characteristics.

How to burn wood at home: a step-by-step guide

How to choose the right type of wood?

The first thing you need to decide on before starting work is choosing the right type of wood. The original Japanese wood burning technology Shou Sugi Ban involved the use of only cedar, but over time there was a gradual accumulation of experience in this technique, and views changed somewhat. Today it is believed that any wood is suitable to create the effect of burnt wood, but true connoisseurs of visual delights prefer species with the most pronounced and original texture. These varieties include soft coniferous woods - pine and spruce, characterized by a clearly defined pattern of annual rings.

Burnt beech and hornbeam wood, characterized by its increased density, will look no less original. This causes only the top layer to burn through, due to which the wood acquires original shades of gray and anthracite.

No less popular are valuable types of wood - maple, alder and poplar, which, after undergoing the firing procedure, acquire the famous elongated texture, as well as larch and walnut, on the surface of which fancy small textured patterns are formed. When preparing material for the construction and finishing of a bathhouse or sauna, pay attention to birch - after firing it becomes very porous, due to which it acquires a low heat capacity and does not burn the skin when it comes into contact with it after heating.

How to prepare material for firing?

The material to be fired requires careful preparation. It is important to ensure that its surface is clean, dry and smooth, paying special attention to the absence of moisture on the surface. The wood moisture content should not be higher than 13-15%, since otherwise exposure to high temperatures will lead to the formation of stripes and spots on the surface of the material, which will significantly reduce the quality of the work performed. It is also important that no traces of paints and varnishes (paint or drying oil) are found on the surface of the wood, since after firing they will take the form of spots and appear unevenly on the surface. However, this largely depends on the time of exposure to fire and the depth of development of the material.

Important! The ideal material for firing is freshly processed wood that has not had time to change its color and texture. Otherwise, it will need to be sanded again.

How to burn wood with a blowtorch?

Before you start firing, you need to wait until the nozzle of the blowtorch turns red and the fire acquires a uniform purple hue.

Important! Yellow fire cannot be used to burn wood, since in this case the surface of the material being processed will be covered with soot.

In order for wood burned with a blowtorch to meet all the required standards, during its manufacture the fire must be directed perpendicular to the board and held in such a way that only the end of the torch, where the temperature is highest, comes into contact with the surface of the material. During operation, the fire is moved slowly at a uniform speed, remembering that the latter depends on the temperature of the fire and the degree of dryness of the wood. In addition, it is necessary to monitor the uniformity and contrast of the pattern. To make work easier, it is recommended to place the material being processed on stools, and 4-5 boards can be placed on them at a time, close to each other. The fired boards are nailed to the wall in the same order in which they lay on the stool during firing.

Important! In accordance with fire safety regulations, it is prohibited to burn boards nailed to the wall.

Important! If you want lumber with a contrasting pattern, consider softwood.

After you have fixed the boards to the wall, they must be covered with drying oil or nitro varnish. You can also use urea-formaldehyde varnishes.

Remember that prolonged exposure to direct sunlight reduces the contrast of wood burnt with a blowtorch, and therefore it is not recommended for use for external cladding of house walls located on the sunny side. On average, the contrast of wood under such conditions will decrease after two months.

How to burn wood with a gas torch?

The gas burner is used only for surface firing of lumber. This is due to the fact that deeper aging of wood in fire, as a rule, is not uniform, which contributes to the uneven thickness and width of the product.

When burning wood with a gas burner, only the edge of the torch, which has a light blue tint, comes into contact with its surface. The movements in this case are similar in intensity, speed and scope to those during painting. The depth of firing during the processing of the material can be easily controlled by the degree of change in its color.

After the part has been fired, its surface is wetted using a hand sprayer. The time interval between firing and sprinkling should be the same for each section of wood, and therefore it is important to process each part consistently. After the wood has cooled, it is necessary to clean off the soot and carbon deposits formed during the firing process. To do this, use brass brushes, which will carefully remove soot without damaging the surface of the material. In the process of mechanical processing, it is possible to additionally artificially age the wood or so-called brushing.

Important! Color solutions for furniture and finishing materials made of burnt wood are distinguished by their diversity and are realized through the use of acrylic paint. If you prefer softwood, in particular pine, focus on ivory acrylic paint, which is applied along the grain.

After mechanical processing of the material, you can begin installation of products. The structure of burnt wood does not require additional protection, but, as practice shows, protective measures do take place, and they are carried out mainly to preserve the original operational and decorative characteristics of the material, such as color, contrast and overall appearance. Thus, it is recommended to coat lining made of burnt wood for interior decoration with linseed or hemp oil, which is applied in several layers. Facade wood and other materials for exterior finishing are coated with two layers of colorless nitrocellulose varnish with the addition of synthetic wax, which are applied using a spray gun or brush.

Important! To protect facade wood, it is necessary to use synthetic wax, in no case replacing it with natural wax, since the latter, due to its performance characteristics, will not lose its stickiness after processing. Before using technical varnish, it must be dissolved in turpentine heated to 40-45 degrees.

Burnt wood in the interior

The introduction of burnt wood into widespread production has made it possible to solve pressing issues in the design of interiors and exteriors. If the interior design involves the use of burnt wood for the manufacture of doors, interior partitions and floors, then the exterior line offers materials for the construction of pergolas, balconies, terraces and canopies. A furniture set made of burnt wood, including a table made of burnt wood and a set of chairs, together with finishing materials made of thermal wood, allows you to create a unique harmony in the area being designed.

Today, charred wood continues to be one of the fashionable trends not only in construction, but also in the furniture industry.

Modern designers have learned to use furniture made of charred wood in almost all stylistic directions with a striking aesthetic effect, and today it will become an organic complement to various design concepts, from classic to ultra-modern eclecticism.

How to burn wood video

Stages of work

How to carry out firing at home can be seen using the example of using a standard burner. Let's look at the step-by-step processing of a wooden piece with a gas burner.

1. The flame of the device must be kept calm, even, and bluish. But they don’t burn with yellow fire.
2. To process the wood evenly, you need to run the tool over the surface several times. The movements should be the same as if the board was being painted with a brush. It is more convenient to start from the top. The burnt board should be burnt 4 mm deep.
3. Use a brush or sander to walk along the grain of the wood, trying not to damage the structure of the material. At the same time, the flute is also used.
4. The cleaning process (you need to be prepared for this) is very painstaking and time-consuming. The detached soot must be completely removed. If you ignore this point, the workpiece will not look beautiful.
5. You can check the quality of the work you have done yourself: wipe the wood with a napkin and a soft cloth. To enhance the relief, you can once again use firing followed by brushing.

The result of this work is a relief surface, the shade of which can be from soft golden to rich chocolate. Sometimes a layer of aniline dye is placed on the surface.

How to process wood using Japanese pyrolysis technology.

1. It is necessary to remove the top ash layer from the wood. The boards must be washed in water and then thoroughly soaked in vegetable oil. This will help the wood become moisture-repellent, with antiseptic characteristics.
2. The finished material will become dark silver and shiny. In the old days, this effect was achieved by simply sending the wood into a stove or fire, but today they turn to a burner.

Japanese craftsmen who burned wooden surfaces in this way protected houses from fires. The ash layer is not afraid of fire, therefore the Japanese firing method is optimal for objects and objects located on the street.

Processing a wooden product with a blowtorch is carried out with an extremely heated tool. The fire must be directed only perpendicular to the surface. How long to act depends on the workpiece and the final purposes of firing. All manipulations must be performed measuredly, without haste. The surface should gradually acquire contrast. Then the product is sanded, treated with drying oil or the same varnish.

Types

There are at least 3 heat treatment options. Not only the shade, but also the properties of the wood depend on the type of treatment.

Surface

This option is used more often than others. You don’t have to spend a lot of time, you don’t need special training, and you don’t need to spend a lot of money. This kind of firing is carried out at home: take a blowtorch or gas burner. The wood is burned to a depth of no more than 5 mm.

Deep

This method is popular among those who want to artificially age wood. This type of firing is usually used to decorate timber. The shade of the wood will depend largely on the exposure time. The wood may become graphite, or maybe coal-black, that is, the changes will be dramatic. This dark wood is used to decorate panels and garden paths. The firing depth can reach 20 mm.

Full

And this processing method is less popular, but only due to the fact that it is not available to everyone. The fact is that you can burn wood this way only at a temperature of about 400 degrees. And for this you need vacuum ovens. Therefore, this type of processing will not be widespread. And there is no point in using it for large volumes of wood: they will be halved after processing.

Can a fire happen in a bathhouse at high air temperatures?

This is theoretically possible, but almost impossible. In order for wood to spontaneously ignite in a bathhouse, the ambient temperature must be about 200 degrees. Not a single bathhouse, and especially not a single person, is capable of this.

The record for staying in a sauna belongs to a Swede who was able to hold out for 17 minutes at a temperature of 110 degrees. For many people, a temperature of 90 degrees is considered the maximum possible. With such warming of the air, the load on the heart sharply increases and there is a chance of fainting.

It is still recommended not to leave a bathhouse or steam room heated to more than 100 degrees for a very long time for fire safety reasons. Although the ignition temperature of wood starts at 200 degrees, caution never hurts.

What is the combustion temperature of wood?

It’s hard to meet such a person who has not encountered wood burning in his life. Most people have gone on a hike at least once, which is not complete without lighting a fire. Some have a lot of experience in lighting house stoves and sauna stoves. Most people have tried wood burning at least once in their lives with a specialized device or a magnifying glass.

But not all people wondered at what temperature wood could ignite. Is there a difference between the combustion temperature of different types of wood? The reader has a unique opportunity to delve into these issues and obtain a lot of valuable information.

Fire safety when working with wood

Natural material easily catches fire. Any careless act can lead to an unpleasant or dangerous situation. Wood has different combustion temperatures. It depends on the breed. But they are not too big.

To maintain safety, you must do the following:

• use wet plaster;
• use fire retardant pastes;
• do cladding;
• use varnishes, enamels;
• apply fire retardant.

This will help protect yourself when working with wood.

How did man master fire?

Fire was known to people who lived in the Stone Age. People absolutely could not always make fire on their own. Man's first acquaintance with the combustion process, according to scientists, happened empirically. Fire, obtained from a forest fire or conquered from a neighboring tribe, was protected as a very expensive thing that people had.

Over the course of some time, people have noticed that certain materials have qualities that are more conducive to combustion. For example, dry grass or moss can ignite with just a few sparks.

Over the years, again empirically, people learned to make fire using improvised means. Historians call man’s first “lighter” tinder and flint, which produced sparks when they struck each other. Later, humanity learned to make fire using a twig placed in a special recess in the wood. The ignition temperature of the wood was achieved due to the intensive rotation of the end of the twig in the recess. Many Orthodox communities continue to use these methods today.

Much later, in 1805, the French chemist Jean Chancel invented the first matches. The discovery became widespread, and a person could safely draw fire if necessary.

Mastering the combustion process is considered a decisive factor that gave impetus to the formation of civilization. In addition, in the near future, combustion will remain such an argument.

How does wood burn?

Not all wood burns the same. Some of them disappear almost completely in the furnaces, leaving only a handful of ashes in their place. Others smoke for a long time and tediously, clogging the entire combustion space with the remains of their combustion.

The speed and completeness of firewood combustion also depend not only on the chemical reactions occurring in the open flame, but also on the design of the stove. High-quality stoves have a rather complex structure, which includes many elements, such as a spool and ash pan, a firebox and grates.

The completeness of combustion of firewood will also be affected by its species, as well as (to a very significant extent) specific humidity.

burning wood

But strictly speaking, when calculating thermal devices, they usually do not take into account the different characteristics of firewood prepared from different types of wood. For calculations, the average statistical value is taken, which is 3800 calories for wood

Which wood burns hotter than others?

In addition to the calorific value, which characterizes the amount of thermal energy released when burning wood, in the course of practical life we ​​may also be interested in heat output - that is, the maximum temperature that can be achieved in the firebox when burning one or another type of wood.

Different fuels and different types of wood burn in different ways. Some of them can produce an even and high flame, while others will demonstrate a low fire, but show a high temperature directly in the combustion area.

firewood heat output

There are two main points that affect the temperature produced by wood during combustion.

First of all, the combustion temperature depends on the intensity with which the oxygen necessary for combustion enters the firebox. This indicator is usually determined by the design of the firebox itself.

The design of the furnace itself also affects the temperature.

Stoves and fireboxes can be made from different materials. And each of the materials can have a special effect on the combustion temperature of firewood.

In a massive stone stove, the wood burns almost completely, but this process takes a relatively long time. On the other hand, a potbelly stove, that is, a firebox made of a thin steel sheet, cools down very quickly, distributing heat to the surrounding space. In this case, heat from the combustion zone is constantly transferred to the walls and further into the room. As a result, the firewood in such stoves burns with virtually no residue.

How to measure the burning temperature of wood?

You are unlikely to be able to measure the burning temperature of firewood with a regular thermometer. Moreover, it is completely lost to determine the combustion temperature “by eye”. In order to conduct such research, you need to stock up on a special device - a pyrometer.

But note that the highest burning temperature of firewood does not mean that firewood of this type can release more heat.

Please note that in good combustion devices, for example in closed fireplaces, it is possible to artificially reduce the supply of oxygen from the air to the burning wood, thereby increasing the combustion temperature and reducing heat transfer.

For comparison, you can look at another plate, which reflects the calorific values ​​of various types of fossil fuels.

calorific value

Consequences of heating wood

A process where an area of ​​rock is exposed to an external heat source and fire appears.
It could be paper set on fire with a match, or something else. What is the combustion temperature of paper? Paper can ignite if there is an ignition source on its own, releasing light and heat. At a temperature of 120-150°C, the wood begins to char. Self-igniting coal is formed.

When the degrees reach 250-350°C, the material will begin to thermally decompose into its components. The surface of the tree will begin to smolder, but the flame cannot be seen. Brown smoke will appear. The breed has already warmed up and is ready to move into a new stage.

Ignition

The initial stage of the combustion process in which thermochemical reactions are accelerated. Activates at temperatures of 460 degrees and above.

Ignition is affected by volume, humidity, external heat source, draft and other factors. If the rock is wet, the ignition process is difficult.

Additional energy is required to evaporate water. Also, thermal conductivity slows down. A massive round tree burns worse. Rectangular with a small cross-section - good. An unplaned wood surface is more likely to ignite than a smooth surface. It is also important that there is enough oxygen supplied. Otherwise you will have to wait a long time for the fire.

Self-ignition

The process is possible without the influence of external sources. For example, a certain area of ​​the rock is overheated. It starts to char. Charcoal reacts with oxygen. A flammable mixture appears above the surface.

High temperature ignites the formation. Smoldering charcoal appears on the fibers of the boards. To avoid spontaneous combustion, especially if the rock is located near fire sources, you need to remove uneven areas. Then the emergency will not happen.

Combustion products

In the process, gaseous particles and solid particles turn into smoke. Their composition depends on the type of wood. These are compounds of chemical elements with oxygen.

Combustion products are:

• carbon dioxide;
• water vapor;
• nitrogen;
• carbon monoxide;
• sulphur dioxide.

The listed products cannot burn in the future. Except for one exception. It is carbon monoxide. Particulate matter in smoke is soot. The composition of the products depends on the combustion conditions. It may or may not be complete.

If there is not enough air, acrid smoke appears. It is very dangerous for humans. Often inhaling it in large quantities is fatal.