How to properly varnish a wooden surface. Varnishing wood with a brush

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Coating wooden products with varnish is one of the most common methods of decorative processing of painted and unpainted surfaces. The use of varnishes is a universal finishing method, as it is suitable for most types of wood, regardless of the density of the materials and their texture. This finishing method is widely used in the manufacture of furniture, in the finishing of buildings made from lumber, etc.

When planning to purchase varnish to coat wood, you need to understand that the quality of the finished result largely depends on a number of conditions, including: the degree of preparation of the surface, the correct selection of varnish in accordance with the type of wood, and compliance with the technology for using paints and varnishes.

In this article we will talk about the features of the selection and use of varnishes in combination with the use of pigment compositions for wooden surfaces.

LMB selection

There is a wide range of paint and varnish materials on sale, but not all of them are intended for processing lumber.

The following types of paints and varnishes are used for application to wooden surfaces:

• Alcohol varnishes are transparent and translucent coatings that add shine and protect the rough surface from the negative effects of factors. external environment. A correctly selected coating, if applied correctly, can highlight the texture of the fibers and enhance the tone of the wood, which guarantees obvious advantages when finishing furniture.

Alcohol-based varnishes are complex solutions containing film-forming substances such as shellac, sandarac, copal or synthetic resins. Ethyl alcohol is used as a solvent.

A separate type of alcohol-based paints and varnishes is polish. Such compositions contain about 30% shellac resins and 70% ethyl alcohol.

Important: In order for alcohol varnishes to form a sufficiently durable coating, the strength of the alcohol used must be at least 90°.

• Oil varnishes, the price of which is low, are complex compositions consisting of a certain amount of resins and pigments mixed in oil.
  The finished varnish has a liquid or semi-liquid consistency, and therefore can be applied with a brush or roller. After application, the solution dries, forming a transparent film on the surface that is resistant to precipitation and mechanical stress. Therefore, oil-based varnishes for impregnating wood are an excellent means for finishing country furniture, which spends most of its time outdoors.

Important: Most oil-based varnishes have a characteristic yellowish tint that does not disappear after the applied layer has completely dried.

• Nitrocellulose varnishes (nitro varnishes)– these are compositions prepared on the basis of nitrocellulose diluted in organic solvents.

Important: Considering the toxicity of fumes when nitro varnishes dry, during their use it is necessary to use a respirator and work in well-ventilated areas.

Nitrovarnishes, regardless of how they are applied, form a smooth and hard coating that is resistant to UV radiation and mechanical stress. Nitrocellulose-based coatings take a long time to dry; in order to speed up the drying process, the content of organic solvents in the composition increases.

Due to the toxicity of organic solvents, the share of production of nitro varnishes is decreasing everywhere in comparison with the volume of production of similar alcohol- and water-based compositions.

• Water-based varnishes are compositions made using an acrylate base mixed in an aqueous environment. The finely dispersed acrylate base does not dissolve in water, but is suspended particles. Therefore, the product is thoroughly mixed before use.

Once applied to the wood, the varnish layer dries to form a dense, hard coating. After complete drying, the finishing layer demonstrates resistance to water, UV radiation and mechanical stress.

Water-based varnishes are widely used in the modern furniture industry, as well as in finishing the interior and exterior of construction projects built from lumber. A significant advantage of water-based varnishes is their environmental safety, and therefore finishing work can be carried out without a respirator.

So, we have looked at the main types of paints and varnishes suitable for processing lumber, and you can decide which varnish to coat a wooden door or other wooden surfaces with.

Drying time

In order to know exactly what varnish to coat a wooden table with, you need to have a general idea of ​​the drying rate. You can see these parameters in the following table.

Water-based varnish application technology

After we decided on the choice of product, it remains to figure out how to properly varnish the wood. As an example, let's look at the features of using water-based acrylic paints and varnishes.

The instructions for finishing work are as follows:

• At the initial stage, preparatory work is carried out, during which the surface is brought into an optimal state for applying paint and varnish.
  First, the surface is sanded to remove roughness and dirt, then the products treated in this way are brushed to remove dirt and dust.
  If there are areas affected by mold on the surface of the wood, it is necessary to use special bleaches and conventional antiseptic solutions. After graduation preparatory work It is necessary to keep the product indoors so that the humidity level is no more than 10%.
• At the next stage, thoroughly mix the varnish, bringing its consistency to a homogeneous consistency.

Important: All subsequent work must be carried out at an air temperature of at least +10 °C.

• Apply wood varnish using a brush or roller. We move the tool along the direction of the fibers in order to emphasize their texture.
  After one coat has been applied, wait the time required for it to dry to touch. Then we inspect the surface for uniformity of coating.
  If the layer is unevenly absorbed into the wood, wait until it dries completely, after which we apply the varnish again in a thin layer. It is allowed to apply paintwork in several layers until the optimal appearance of the coating is obtained.

Important: If finishing work is carried out on surfaces with a large area, the applied composition should be diluted to obtain a more liquid consistency and used in combination with a spray gun.

Using varnish in combination with stain

Coating wood with stain and varnish is a unique opportunity to give ordinary lumber the appearance of rare and, as a result, expensive wood species. The choice of stain depends on the type of varnish used.

As an example, let's consider the technology of applying a one-component water-based stain followed by applying a water-based varnish. The choice of finishing materials is not accidental, since water-based compositions are easy to use and can be applied with your own hands using a regular brush.

The instructions on how to properly coat wood with stain and varnish are simple. Dip the brush into the stain and apply it to the previously prepared surface along the grain. When applying the composition, rub it thoroughly with a brush so that it penetrates into all the recesses.

The stain, when absorbed into the wood, will give an uneven shade: it will be lighter between the fibers, and darker at the tops of the fibers. This is due to the different densities of wood.

In order to even out the shade, you can apply a second layer of stain. But, if you want the texture to be visible, it is better to do with one layer. After the stain has completely absorbed and dried, you can apply varnish.

Conclusion

Now you know how to varnish wood. Still have any questions? More useful information you can find it by watching the video in this article.

The choice of furniture in modern furniture stores is quite wide, as is the material from which it is made. But products made from natural wood have not lost their attractiveness. For example, a kitchen set made of solid wood. Such a product will be 2-3 times cheaper if you order it from a craftsman. You can try to assemble it yourself, even better. That parts for such furniture are also widely available in stores. But, we will talk about what kind of varnish to cover a wooden table so that the furniture is protected from all kinds of damage and is pleasing to the eye.

Varnish selection

Preferences in choosing a paint material depend only on consumers. Our task is to familiarize them with the properties of each type. Varnishes for table coverings are:

• Water-based are the most environmentally friendly. The substance is almost odorless and does not pose a health hazard to the consumer. Water-based varnishes are most often used for children's furniture. But professional craftsmen rarely use them, since after drying the treated surface becomes matte.
• Acrylic-based materials are affordable and quite easy to process. It is best for beginning craftsmen to start with these varnishes. If mistakes are made during the work process, they can be easily corrected. To do this, use white spirit or grind the surface.
• Polyurethane based and recommended for professional craftsmen. It is better to apply this substance by spray. In this case, the surface will look quite stylish. It is better to purchase such material in branded stores.
• For very expensive wood, specialized furniture oils are used. This composition is quite expensive, so it is rarely used. Apply only by hand using a swab.

For beginning craftsmen, a very important question is what shade to choose varnish for a wooden table. The customer must also put an end to this issue. You can not disturb the natural texture of the wood or cover it in the color of cherry or walnut. But you don’t always get the result you expect. To prevent this, you should familiarize yourself with some features:

• Colorless varnish will not always preserve the original appearance of wood. Most often it gives the wooden surface a yellowish appearance. Therefore, if it is necessary to maintain the original shade, it is better to use polyurethane materials. They eliminate the appearance of yellowness.
• When visiting branded stores, sellers will provide a large assortment of colors to choose from. To get the color that you prefer, it is better to take a color that is 2-3 tones lighter. After all, the desired gloss on a wooden surface is formed only after applying 5 or 6 layers. With each subsequent layer, the shade will become darker.
• In the case when 2-3 layers are applied and the result is the desired surface color, but the required gloss is achieved, then this problem can be solved with the help of colorless varnish.
• Varnishing should begin only after high-quality sanding has been completed.

Technology of varnishing a wooden table

Before starting work, you should figure out how to varnish a wooden table. First you should worry about how to protect your respiratory system. To do this, you need a dust respirator or mask. Also, work is carried out only in rooms that are well ventilated. To varnish a table correctly, we present some algorithm.

Preparing the surface

Surface preparation plays a very significant role in the quality of varnishing a wooden table. First, you should stock up on tools for sanding a wooden surface:

• sandpaper of varying degrees of grain;
• a piece of wooden block;
• a piece of rubber;
• long stick.

The wooden block must be wrapped with sandpaper and secured. This method will greatly facilitate the work and help make the surface perfectly clean. Using a block with sandpaper, smooth surfaces are processed.

If you need to process rounded surfaces, it is better to use a piece of compacted rubber and also wrap it with sandpaper. The holes are processed with a stick and sanding paper.

Correct processing is achieved by smooth movements along the grain of the wood. This method will prevent the formation of scratches on the table surface. You need to start with coarse sandpaper and gradually reduce the grit until you get to the minimum grit.

If scratches do form, the area must be moistened, allowed to dry, and then the sanding process repeated with fine-grained sandpaper.

Priming process

Before varnishing the table, the wooden surface should be primed. It is the primer that will close the pores in the wood and much less varnish will be required. The following compositions are used for priming a wooden surface:

• liquid wax;
• turpentine to which wax is added;
• a mixture of PVA glue and wood powder;
• a solution of wood glue and water.

The primer is applied to the surface using an aerosol can or brush. Then leave it to dry for a while and re-treat it with fine-grained sandpaper.

Important: before applying varnish to the table surface, thoroughly remove all dust.

Applying varnish

Painting a table with varnish consists of the following steps:

• Cover the table with stain in a small amount. At the same time, we do not allow the formation of greasy strokes and drips. After application, wait for the stain to dry completely.
• The second layer is applied after the one already applied has stopped sticking. Sometimes you have to apply several layers of stain. To give the surface a glossy finish, it is sometimes necessary to perform intermediate sanding.
• After the required shade has been achieved, they begin to open the surface with colorless varnish. The varnish should also be applied evenly, without smears or drips.

By following all the rules given in this article, novice craftsmen will be able to do their work easily and quickly. Read more about other options

From this article you will learn:

• Why varnish wood?
• What kind of varnish can be used to do this?
• What is the best way to varnish wood?
• What to do before varnishing wood
• How to properly varnish wood
• What mistakes to avoid when varnishing wood

Wooden products are considered one of the most exquisite and unusual. However, for a long service life, wood requires special protection. For these purposes, you can use paint, but if you want to emphasize the structure of the material, it is better to coat such objects with varnish. At first glance, the work process should not cause any difficulties, but, as in any business, there are some nuances. Read our article about how to varnish wood and still get a high-quality result.

What varnish to coat wood with?

Varnish is a universal means of coating all types of painted and unpainted wood. The manufacture of wooden furniture, accessories, as well as wall and floor cladding is rarely complete without its use.

Wooden surfaces need to be varnished for several reasons:

• it perfectly protects against moisture, insects and other aggressive influences, including mechanical ones;
• is able to highlight the unique texture and natural color of wood, therefore in some cases it is a tool for bringing design solutions to life.

Modern manufacturers offer a large number of varnish compositions that can be used to coat wooden surfaces, and each product has its own unique characteristics.

The most popular varnishes include:

1. Oily. They contain solutions of synthetic or natural resins, which allows the formation of a fairly dense yellowish layer on the treated surface. In most cases, such materials are used to cover walls and floors in private homes.
2. Alcohol. They are solutions of plant resins or polymers in alcohol, which are used for priming wood after sanding. The compositions in question are not intended to protect wooden surfaces from moisture, but with their help you can add shine to the wood and make it more durable.
3. Alkyd. Manufactured using synthetic resins with special solvents. Alkyd varnishes can be used to perform facing work in different conditions. They are often used to repair facades, walls and floors in private homes. They are resistant to moisture and increase the strength of wooden surfaces.
4. Nitrocellulose. They are made from nitrocellulose, which is diluted in special solvents using plasticizers. Such varnishes form an absolutely colorless layer on a wooden surface. Applying several layers helps increase the strength of wood by an order of magnitude.
5. Acrylic. The compositions under consideration are based on the action of acrylic resins. These are environmentally friendly and safe compositions that are durable and resistant to light. Such varnishes are used only for interior finishing work.
6. Polyurethane. They provide reliable protection for wooden products and are often used in the production of musical instruments and for floor varnishing.

Regardless of what type of varnish you use, work should be carried out exclusively in accordance with the manufacturer’s instructions. This way you will definitely get a reliable coating that will protect the wood from negative factors.

What is the best way to varnish wood?

After you select the appropriate composition with which you will coat the tree, you will have to carry out the work process. There are three main methods that allow you to coat a surface with varnish quickly and efficiently. The choice of a specific method depends on the surface area, its purpose and design intent.

• Application with a brush.

This is the traditional and most common method, since in most cases you can choose a suitable brush for any surface.

This tool allows you to coat products with high quality, painting over all the unevenness of the wood. The bristles of varnish brushes can be artificial or natural.

Try to pay enough attention to choosing the right brush, because the final result will depend on this. To varnish a flat surface (for example, a wooden table), it is better to buy flat brushes, and for surfaces with a lot of small details, it is recommended to choose small round ones. In cases where the product that needs to be varnished is very small in size, you can not use a brush, but completely dip it in the varnish composition.

• Application using a roller.

Another commonly used tool for covering wood surfaces is a roller. If you need to varnish a large area of ​​wood, a roller will help significantly speed up the work process. All such devices have individual characteristics, but for working with wood it is better to choose foam rubber or velor.

• Application with a spray gun.

This method is used mainly by professionals. It is indispensable when processing large work surfaces. The spray gun allows you to evenly apply the material over the entire area of ​​the wood being treated. When working with a sprayer, it is important to remember safety precautions: varnishing wood should only be done with special masks and in a well-ventilated area.

It is worth noting that small wood products can be covered with a foam rubber or fabric swab. But make sure that the material chosen for varnishing wood does not have long fibers, since there is a high probability that some of them will remain on the surface along with the layer of varnish composition.

What to consider before varnishing wood

1. Choose a well-lit and ventilated area.

Sufficient lighting will allow you to see and immediately correct defects in the work: bubbles, brush streaks, dents and bald spots. Fresh air in the work area is also very important, since many varnishes and solvents have a specific odor that can cause dizziness and nausea.

If you smell too strong a smell, immediately open a window or turn on a fan.

1. Choose a clean room.

The area where you plan to varnish the wood should not be dirty or dusty. Before starting work, it is recommended to sweep, vacuum or wet clean to avoid dirt getting onto the varnished surface.

1. Pay attention to temperature and humidity.

The optimal temperature for the workroom is between +21 °C and +26 °C. If it is too high, the varnish will dry out very quickly, resulting in air bubbles forming on the surface of the product.

And if the room is cold, the drying time of the varnish composition will increase significantly, and dust will have another chance to settle on the wet varnish.

1. Wear suitable protection.

Most lacquer compositions contain chemicals that can cause negative reactions when interacting with exposed skin or ruin clothing. Before starting the work process, it is better to put on safety glasses, gloves, and things that you don’t mind getting dirty or damaged. Respiratory organs can be protected with a dust mask or respirator.

Preparing the wood surface for varnishing

In order to properly varnish a wooden surface, it is necessary to carefully prepare it for the application of this material:

1. Clean the wood thoroughly, remove dust, dirt and remnants of the previous coating. Neglecting the described actions can lead to the coating becoming uneven and also losing its protective and aesthetic properties.
2. Apply a protective agent. It is selected individually in each case, depending on the characteristics of the operation of the surface to be varnished.
3. Treat with primer. This stage allows you to improve the adhesion of the varnish to the wood. If you plan to coat wood inside a building (house), it is better to choose compounds that do not contain toxic substances.

Don't forget about the right room, otherwise you risk getting results that disappoint you. The temperature in the room should be constant, without sudden fluctuations and equal to +20 °C. There should be no dust or dirt inside the workspace, as even barely noticeable dust particles can spoil the final result.

Before starting work, you should prepare necessary materials and tools:

• different types of sandpaper (fine-, medium- and coarse-grained);
• rectangular wooden block;
• rubber layer;
• small diameter stick.

Before covering wood with water-based varnish or stain, it is necessary to carefully prepare it: sand it, collect the resulting dust with a vacuum cleaner, and wipe it with a cloth soaked in a solvent.

The parts of wood to be painted should be pre-treated with an abrasive. First with coarse-grain sandpaper and then with fine-grain sandpaper.

For these purposes, you can use a block: wrap it in sandpaper and sand smooth surfaces. Just try to follow the correct wood processing technology: you should move the sanding along the grain so as not to injure the surface.

When processing volumetric parts, rubber is wrapped in sandpaper, and when processing holes, a stick is used.

In order to preserve all the properties of wood, before coating it with varnish or stain, it must be treated with impregnation. The latter is selected based on several factors: operating conditions of the wooden surface (indoors or outdoors) outdoors), temperature conditions and climatic features.

• Antiseptics.

Water-based antibacterial impregnations help prevent mold or mildew from appearing on wood. Their composition contains toxic substances, and therefore such mixtures should not be used for treating surfaces in residential premises.

• Fire retardants.

This type of impregnation not only reduces the natural flammability of wood, but also helps prevent the rapid spread of fire in the event of a fire. These products are used to cover wooden surfaces that are located close to fire sources.

• Insecticidal compounds.

Reliably protect wood from annoying insects. Such compositions must be used to coat wood products that will be located outdoors (garden furniture, benches, etc.).

• Water-repellent impregnations.

They are widely used to protect wood from swelling when wet, cracking and deformation when drying. The composition of the product penetrates deep into the material, clogs the pores of the wood and, after drying, provides a reliable water-repellent layer. The use of such impregnations is relevant for products that will be located in damp rooms and outdoors.

• Combined means.

They are called impregnations that combine several functions (for example, protect against insects and mold). They are used in cases where the surface will be exposed to several aggressive factors at once. Of course, you can sequentially use several products for different purposes, but this will require much more time and money to protect wooden surfaces.

The next stage is priming wood products.

The main purposes of surface priming are:

1. Additional leveling of the base. Even the finest grinding grain cannot make the surface perfectly smooth. All grains leave streaks on the wood, even microscopic ones. If you do not see them immediately, then after varnishing they may well appear. Plus, in order to properly sand a wooden surface, it takes a lot of effort, patience and time. Usually we always lack the last components.
2. Increasing the strength of the “adhesion” of varnish to wood. Despite the fact that wood is quite hygroscopic, it requires an additional layer before varnishing for a more reliable “adhesion”.
3. Reduced substance consumption. Everything is clear here. For a perfectly smooth surface, the thinnest layer of varnish is required. In most cases, it is enough to varnish the wood just once.

When choosing a primer, you should pay attention not only to the degree of toxicity of the liquid (do not forget that it is not recommended to use toxic agents for residential premises), but also to its composition. It must have a structure that is compatible with water-based stain or varnish. Otherwise, there is a risk of coating delamination and bubbles.

• Alkyd primer.

Most often it is used to cover wooden surfaces in rooms with high humidity or outdoor objects. This solution is used to treat floors and walls in baths (saunas) before painting. The main properties of alkyd compounds are filling the pores of wood and protecting fibers from swelling.

• Acrylic primer.

It penetrates deep into the material, does not contain toxins in its composition and dries quickly on the surface.

The acrylic composition can be supplemented with various components to improve the protective characteristics. For example, liquids for pre-treatment of wood can be added to them, which act as impregnation.

The water-based primer can be used for both exterior and interior work. Acrylic compositions have an insignificant degree of toxicity, but they all require careful and long drying (at an air temperature of +20 ° C, the surface will dry for almost a day). Acrylic primer protects wood from fungus, moisture and rot.

• Epoxy primer.

Epoxy resins in the primer make it possible to create a high-quality moisture-proof layer on wood surfaces. This composition dries quickly and has a high level of toxicity; therefore, surfaces can only be coated with it outdoors. A similar primer is often used in regions with high humidity and frequent precipitation.

The product in question has its own characteristics: it consists of two active components, which are mixed immediately before application.

• Shellac primer.

It cannot be said that it is used more often than others, since only raw wood can be coated with this product. The composition contains alcohol and other components that accelerate the drying process of wood, while simultaneously reducing its deformation.

It should be noted that wood varnish itself cannot radically change appearance processed product. However, you can pre-tint the wood, imitating a particular species. Before covering wood with toner, the composition should be heated to +50 °C. It is recommended to dry the treated wood naturally at a temperature of +20 °C (such products cannot be left in the sun). Once it's dry, you can polish it a little more.

You need to choose the right toner based on the type of wood:

• Walnut - pine, aspen, plum;
• Ebony - birch, pear, maple;
• Mahogany - linden, beech, walnut.

When tinting coniferous wood, you must first get rid of the resins. To do this, simply wipe the surface with acetone, soda solution or gasoline.

How to properly varnish wood: step-by-step instructions

1. Prepare the varnish for the first coat, if necessary.

There are types of varnish products that do not require preliminary preparation wood (for example, in the form of a spray). Some formulations must be diluted to apply the first coat. This helps seal the wood and helps prepare the surface for subsequent coats. After the first application, the varnish does not need to be diluted.

If you decide to coat a wood surface with an oil-based varnish, you need to dilute the composition with paint thinner (for example, turpentine). Keep the proportions - 1:1.

If you want to cover wood with acrylic varnish or a water-based composition, then water should be used as a thinner in a similar proportion (1:1).

1. Apply the first coat of thinned varnish and let it dry.

It is better to coat wood with varnish using a flat brush or foam roller. The surface should be painted with even strokes along the wood fibers. Drying time for the first layer is approximately 24 hours.

If you purchased varnish in the form of a spray, then it should be applied in a thin, even layer at a distance of 15-20 cm from the surface. Drying time is usually indicated on the packaging.

1. Sand the first layer and wipe it with a damp cloth.

The initial layer of varnish on the wood must be leveled. For these purposes, you can use 280 grit sandpaper, after which dust and dirt should be removed with a dry cloth.

Don’t forget to also wipe your work area so that dust particles do not interfere with further work.

After applying the coating, the brush must be cleaned in solvent (if you used an oil-based varnish) or in water (if you used a water-based composition).

1. Apply the next layer of varnish to the wood and wait until it dries.

To coat a piece of wood with a new coat of varnish, you can use a clean brush or a new foam roller. Remember that varnish should be applied along the wood fibers. For this layer there is no need to dilute the varnish. The drying time for a new layer is also 24 hours.

When working with wood varnish in the form of a spray, you must apply it in the same way as the first layer. Do not make the layers too thick, otherwise drops and smudges may form on the wood.

1. Sand the second layer and wipe the surface with a clean, damp cloth.

After the second layer of varnish has dried, it must be sanded with 320 grit sandpaper. Be sure to remove any resulting dust from the wood surface and work area.

1. Continue applying layers of varnish and sanding.

It is necessary to cover the wood product with two or three more layers of varnish. Remember that each layer of varnish must be thoroughly dried, sanded and dust particles removed before applying a new layer. The wood must be varnished along the grain. There is no need to sand the last layer.

You can determine the required sandpaper grit yourself, but as a rule, it is 320 or 400 grit.

It is recommended to wait two days before applying the final coat of varnish to the wood.

1. Wait until the varnish has completely hardened.

All varnish compositions require a certain time before complete hardening. During this period, it is not recommended to move the wooden product or use it for any purpose. Some varnishes harden within 24-48 hours, while others take 5-7 days. The specific drying and hardening time is always indicated in the manufacturer's instructions.

Typical mistakes in varnishing wood

The varnish does not dry out

Reasons:

• Substances (natural oils, resins, etc.) contained in the thickness of the wood prevent drying. This effect is observed when exotic wood is coated with varnish based on artificial resins.
• Old, wax-impregnated floor - the remains of this substance significantly increase the drying time of PU-, acid-curing and varnishes based on artificial resins.
• Insufficient amount of hardener or its complete absence (for two-component varnishes).
• Low temperature in the working room (does not reach +10 °C).
• High air temperature in the workroom at a low parquet temperature, which entails an insufficient flow of oxygen (difficulty in supplying fresh air).
• Use of an unsuitable hardener (for example, a hardener for PU varnish is added to an acid-curing varnish).

If the varnish composition takes a long time to dry due to specific substances contained in a certain type of wood, or low temperature, it is enough to simply increase the room temperature to +20 ° C and ensure a sufficient supply of fresh air (just do not confuse this with a draft). After some time, the drying process will be activated again and the varnish will dry completely.

If you mistakenly added the wrong hardener, then most likely the varnish will have to be washed off. Sometimes it is enough to apply a thin layer of pure hardener to a surface coated with an acid-curing varnish. But after hardening, the entire surface will need to be sanded.

Cloudy, white spots and tracks appear

Reasons:

• The varnish used at too low a temperature to coat the wood.
• The floor temperature was low and the air humidity was high.
• The overall humidity in the work area has increased (this is especially true for new buildings).

White spots on a varnished surface are evidence that excess moisture has condensed onto a fresh coat of varnish. In most cases, you can get rid of them by wiping them with a solvent (just remember to monitor the content of hazardous substances in the solvent). After these manipulations, you should cover the wood with another layer of varnish, having previously raised the temperature in the room to the desired level.

“Blistering” (swelling) of the varnish

Reasons:

• Incorrect combination of varnish and related materials (for example, solvent-based PU varnish is used with nitrocellulose primer).
• The tool for applying the varnish composition was soaked in cleaner and mixed with the varnish used.

If only part of the varnish layer is swollen, you can sand this area and cover the wood with another layer. But in the case when the entire layer is completely damaged, you should sand off the varnish and re-coat the wood with it.

Bubble Formation

Reasons:

• Too much low temperature varnish
• Very thick layer of varnish coating.
• Direct sunlight on the surface.
• Incorrectly selected tools for applying varnish.

Bubbles appear when a film has already formed on the surface of the varnish layer, and the lower part has not yet set. Solvent vapor rises and tends to rupture the coating, forming bubbles. You can get rid of this defect if you completely sand the outer side and re-varnish the wood.

“Scaling”, layering of varnish

Reasons:

• The temperature in the room or on the floor surface is much higher than permissible values.
• Excessive varnish thickness.
• The surface was varnished very slowly.
• Failure to comply with coating technology or incorrectly selected working tools.

Using a solvent, you can make any varnishing composition less viscous and more fluid. But in most cases, it is enough to simply change the pace of work, reducing the time for adhesion of the previously treated area to the new one. If you are going to varnish wood during the heating season, you should significantly reduce the temperature of the radiators. And try to avoid drafts!

Formation of "craters"

Reasons:

• Unsatisfactory condition of the working tool (especially for rollers).
• Incorrect solvent selected.
• Draft in the work area.
• Very low varnish temperature.
• The wooden surface is contaminated with silicone.

You can get rid of “craters” using thorough (matte) intermediate grinding and no less thorough surface treatment with a metal spatula. After this, the layer applied with a spatula should dry well. There is no need to sand it. Then you need to cover the wood surface with another layer of varnish.

“Craters” often form in drafty areas and in cases where the varnish has been stored for a long time at very low temperatures and is now difficult to distribute over the surface.

"Roughness"

These could be:

• Evenly distributed bubbles.
• Small particles of varnish film from the working container.
• Trapped dust particles.
• Incorrect sanding.

Few places provide comprehensive data on why the problem in question appears. In most cases, roughness appears due to dirt getting into the varnish layer or lumps of varnish from the working container, although it can be determined the real reason only possible with a magnifying glass. Before varnishing wood, make sure your work area, tools, and clothing are clean. If the composition contains solid particles, it must be passed through a sieve.

"Wrinkles"

Reasons:

• The previous layer has not dried sufficiently.
• Application of very thick layers.
• Unsuitable solvent.

This problem is often encountered when applying varnishes based on artificial resins (when they try to cover the wood with too thick layers or deliberately reduce the drying time of the varnishing material). If “wrinkles” have formed on the entire surface, complete sanding is indispensable.

Matte-glossy areas, formation of “clouds”

Most matte varnishes must be applied in layers of a certain thickness (up to 150 g/m2). If you cover the wood with a thicker layer, the matting substances will be distributed unevenly, settling in each fresh coating. This creates matte-glossy areas, especially in the “joining” areas. Intermediate sanding and further painting of the wood with a thin layer of matte varnish will help correct the situation.

Where to buy high-quality and safe paints and varnishes for wood

JSC Raduga has been operating since 1991 (formerly Tsentrmebelkomplekt, Decor-1). The company was organized to supply raw materials to enterprises that are part of ZAO Centromebel.

Today, the company's regular business partners are not only Russian manufacturers, but also leading companies from Germany, Austria, France, Italy, Switzerland, Finland, Poland, and Sweden. Our office is located in the center of Moscow, as well as our own warehouse complex with an exhibition hall of 200 m².

Our warehouses located in the near Moscow region always have a large selection of raw materials, supplies and components for the production of furniture and carpentry. The assortment includes more than 300 types of varnishes and 400 types of dyes, with an emphasis on the sale of varnishes and dyes with a dry residue.

Based on customer requests, our team produces polyurethane enamels in almost all colors in one or two days. We offer adhesives from five leading European manufacturers, natural veneer and lumber - more than 60 types of ordinary, exotic and exclusive species. Front and fastening fittings are constantly available - more than 4,000 items from manufacturers from Europe: Austria, Poland, Germany, etc.

Every month we process applications from more than 1,800 clients. These include both large furniture factories and private entrepreneurs.

Deliveries of goods are carried out throughout Russia. Our company delivers goods throughout Moscow for free. Products are shipped by road to all regions of Russia.

Our company takes the training of its own specialists seriously. Managers systematically undergo internships in companies producing finishing materials in Germany, Italy, Austria, and Finland. Our company employees provide technical assistance to clients.

We invite you to cooperate on mutually beneficial terms! We value our clients and try to find an individual approach to each buyer.

The final result will depend on how correctly the wooden surface is prepared for painting. How can I treat wood before coating it with water-based varnish or stain? What products are best to use?

The preparatory process before coating a wooden surface with varnish consists of:

1. Thorough cleaning of surfaces, removing dust, dirt and old paint. This stage is required, otherwise the coating made with varnish or stain will be uneven and will soon begin to collapse.
2. Applying a protective agent. Which product is best suited in each specific case is influenced by the conditions in which the object being painted will be used.
3. Primer treatment. This is required to improve the adhesion of the varnish to the wooden surface. For interior work, it is permissible to use only water-based products with a non-toxic composition.

Surface grinding

wood sanding

Work must be carried out in a room that provides optimal conditions for drying the surface. The temperature in the room should be constant, without sudden changes, approximately 20 °C. There should be no dust or dirt inside, since even the smallest particles of debris can spoil the coating and make it uneven.

Before you start work, you need to prepare all the necessary materials and tools:

• a set of sandpaper (fine-, medium- and coarse-grained);
• wooden rectangular block;
• rubber layer;
• stick of small diameter.

All surfaces that are planned to be treated with water-based varnish or stain must be thoroughly sanded, the resulting wood dust must be collected with a vacuum cleaner, and the surfaces must be treated with a cloth soaked in a solvent.
The parts of wood to be painted are pre-treated with abrasive. First, use coarse-grained paper, then sand the surfaces with fine-grained paper.

grater for grinding

To simplify the work, use a block - it is wrapped in sanding paper and smooth surfaces are processed. In this case, the wood processing technology should be taken into account: movements should be directed along the fibers so as not to injure the surface.

For large areas, wrap rubber in sandpaper, and for holes, wrap a stick.

Wood protection products

To prevent the wood from deteriorating, it should be treated with impregnation before coating it with varnish or stain.

You need to choose a product taking into account several factors: operating conditions (indoors or outdoors), temperature conditions and climatic features.

Antiseptics

Water-based antibacterial impregnations prevent the appearance of mold or fungi on wooden surfaces. Antiseptics have a very toxic composition, so it is not recommended to use them on products that are planned to be used in a residential area.

Wood protection products

Fire retardants

Such compositions significantly reduce the natural flammability of wood products, and if a fire occurs, they prevent its rapid spread. They are used for surfaces that are located close to fire sources.

Insecticidal compounds

They serve as reliable protection against insects. They are used to treat outdoor wooden surfaces, garden furniture and other items that will be outdoors.

Water-repellent impregnations

They are used to protect wood from swelling when wet, cracking and deformation when drying. Products of this type penetrate deep into the wood, filling the pores of the material, and after final drying they provide a reliable water-repellent layer.

Such impregnations can be used for surfaces of products used in damp rooms and outdoors.

Combined products

Liquids that perform two or more functions, such as preventing insects and mold. They are used in cases where surfaces need to be protected from several potential threats. Consecutive use of several products takes more time and effort, and is more expensive, and combined products in this case are the best choice.

Surface priming

There are soil fluids on different bases.

wood priming

When choosing a primer, it is important to take into account not only the degree of toxicity of the liquid (it is unacceptable to use products that emit harmful compounds in residential premises), but also its structure. The primer must have a composition compatible with stain or water-based varnish. Otherwise, there is no guarantee that the coating will not begin to peel or bubble.

Alkyd

It is recommended for use in rooms with high humidity or for outdoor work. Most often it is used to prepare the floor or walls in a bathhouse or sauna before painting. Properties of this type of primer: filling the pores of wood, protecting against swelling of fibers.

Acrylic primer

Its main advantages: the ability to penetrate deeply into the structure of the material, the absence of toxic substances, and rapid drying.

Water-based acrylic primers can be supplemented with various components to improve their protective properties. For example, liquids for pre-treatment of wood can be added to them, in which case there is no need to coat the surfaces with impregnation.

Water-based primer is used for both exterior and interior work.
It has an insignificant degree of toxicity, but requires careful and fairly long drying (at a temperature of about 20 C, the surface will dry for about 18 hours). Additional properties of the liquid are the protection of wood from fungus, moisture and rotting.

An alkyd primer should be used either in the warm season or under a canopy.

Epoxy primer

Primer liquid containing epoxy resins, creates a reliable moisture-repellent layer on the treated surface. Products of this type are toxic and quick-drying, so they can only be used outdoors. Suitable for areas with high humidity and frequent precipitation.

Using an epoxy primer requires some experience on the part of the individual as the coating consists of two components that must be mixed immediately before application.

Shellac primer

Such mixtures are used infrequently, since they are intended for processing raw wood. These primers contain alcohol and other components that speed up the drying process of wood and reduce its deformation.

After completing these works, the surface of the wood is ready to be coated with water-based acrylic varnish or stain.

Careful selection of protection products and the correct wood processing technology will help create a durable and durable coating.

Varnish coatings, which are well known to us, are used in construction for decorative finishing of the surfaces of walls and other elements of wooden buildings. These coatings reliably protect surfaces from destructive climatic influences, which significantly increases their service life. In addition, they provide them with additional attractiveness. The listed advantages of varnish coatings serve as good reasons for becoming familiar with how to properly varnish wood at home.

Let us immediately note that the technique of varnishing wood surfaces (including preparatory operations for sanding and priming them) is not something completely inaccessible to a beginner. To master it, you just need to strictly follow all the instructions given in the relevant sections of our article.

Preparatory operations

Before applying a varnish coating to a wooden surface, it is necessary to carry out a number of operations that ultimately determine the success of the activities carried out. To properly prepare such a surface for coating, you will need:

• a set of abrasive paper with different grain sizes;
• rectangular block;
• small rubber plate.

The wooden surfaces to be finished (as well as any other elements of the building structure) are first treated with sanding paper. To prepare for covering large surfaces, it is more convenient to use a rectangular block wrapped in a layer of abrasive paper. To process small parts of wooden structures, you can use a rubber plate wrapped in so-called “sandpaper.” Obtaining the required effect is achieved by smoothly moving the block along the wood fibers. Grinding is performed in several passes with gradual transition from coarse-grained skins to finer ones.

If you find small scratches on the surface to be finished, you need to slightly moisten the area and, after drying, treat it again with fine-grained sandpaper.

Padding

Priming the surface before coating it allows you to close small pores in the wood, thereby reducing the consumption of varnish material. For priming, you can use liquid wax, sold in small aerosol cans, or an industrial primer (such as KF 1, 2, etc.). In addition, the following compositions are quite suitable for these purposes:

• natural wax dissolved in turpentine;
• wood powder mixed with PVA glue;
• talc (chalk) diluted with water and well sifted, to which dye is added to obtain the required color.

Regardless of the composition you choose, the primer is applied to the work surface in the usual way and, after complete drying, treated with fine-grained sandpaper.

Application of varnishes of various brands

Currently, the following brands of varnish coatings are most often used:

• varnishes based on oil paints;
• alcohol varnishes;
• nitro varnishes.

Oil varnish is applied to the surface of the wood using a special brush with a bristle attachment. To avoid the formation of unwanted smudges, the brush should be dipped into a container with paint half the width, carefully shaking off excess varnish from it.

The coating is applied using smooth and leisurely movements of the brush, through which several layers of varnish are formed.

The waiting time between the first two applications should be about two minutes, while the third layer is applied no earlier than an hour later. It will take you from 10 hours to a day to dry the finished varnish layer.

Varnishes made on the basis of resins and ethyl alcohol (alcohol varnishes) not only reliably protect the surface being finished from wear, but also perfectly emphasize the texture and pattern of wood.

Before properly varnishing wood, you should apply two so-called primer layers, which are used to further level the surface being treated (filling microscopic cracks). After drying, the surface is once again treated with fine-grained sandpaper until complete removal varnish from the surface. After cleaning from dust, the finished surface is covered with another layer of alcohol varnish and left to dry for several days. After it dries, a final (final) layer is applied, to which dye is sometimes added.

Varnishes made on the basis of alkyd resins and solvents have a short drying time (about 15-30 minutes) and are used not only in furniture production, but also when finishing building surfaces made of wood (with the exception of floors). Nitrovarnishes are applied by spraying to form several working layers with intermediate polishing of each of them. Small surfaces can be varnished using a soft brush.

Video

For more information about the types of varnishes and the features of their use, see the following video: