33860 0
Varnish for exterior woodwork is designed to protect products that are used outdoors from negative factors: ultraviolet radiation, pests, high humidity. Accordingly, special attention should be paid to the selection and application of compositions, because in stores they are presented in a huge assortment. How to choose and apply correctly wood varnish for exterior use, we will talk in this article.
Today there are many compositions for coating wooden surfaces, but varnishes have one serious advantage - they allow you to preserve the unique and inimitable structure for which this natural material is valued.
Paints and varnishes are divided according to several criteria, one of which is the conditions under which the wood will be used. Products that are under open air, are exposed to weather factors, due to which the tree constantly swells and contracts. Varnishes intended for treating external surfaces form an elastic film on the surface of the material, which allows the wood to withstand regular swelling and drying. Compositions for treating indoor surfaces do not have a sufficient degree of elasticity, so the film will quickly crack and begin to peel off.
Varnishes for external use are used to cover the following elements:
Compositions that are intended for such purposes must reliably protect surfaces from negative factors, mechanical damage, and also have good decorative qualities.
At their core, all varnishes are mixtures of substances that can form on the surface of the material. protective film. To extend the service life wooden products, the composition for outdoor work must have a number of important characteristics.
The composition of varnishes for external woodwork may include substances that protect the material from pests, components that give the surface a glossy shine or dullness, and much more.
There are several types of paint and varnish compositions that are used for exterior woodwork, and each of them has its own characteristics, advantages and disadvantages. The choice of a specific product depends on the characteristics of the material, the operating conditions of the product, as well as the final result that needs to be obtained.
The basis of such products are purified, heat-treated oils, which give the compositions the necessary properties. The quality of the varnish coating directly depends on the quality of the base, so saving on products is not recommended. The second component of such varnishes is synthetic or natural resins, and most of the compositions sold in stores contain synthetics. The drying time of the compositions is quite long, so it is better to carry out work on clear days at air temperatures above 10 degrees and average humidity.
Important: when varnishing oil based The surface of the wood may darken slightly.
Depending on the proportions of resin and oil, compositions are fatty, semi-fat and lean. For the treatment of external surfaces, exclusively fatty varnishes are used (2 parts oil and 1 part resin), as they are characterized by resistance to atmospheric influences.
Varieties of such compositions are yacht and polyurethane varnishes. The first option is used for surfaces that are constantly in contact with water. Yacht (urethane-alkyd) varnish creates an elastic film on the surface that maintains integrity even as the wood contracts or expands.
HELO YACHT - urethane-alkyd quick-drying varnish
Important: applying yacht compounds requires mandatory priming of surfaces and care when carrying out work. The film that forms on the surface must be solid and dense. If moisture gets under it, the wood will begin to deteriorate from the inside and the product will lose its original appearance.
Polyurethane compounds are easy to work with and provide high quality coating even if the master does not have the appropriate skills. They dry quickly and protect the surface well from abrasion, mechanical damage and ultraviolet radiation.
Compositions based on alkyd resins and solvent provide stable, durable and reliable coating of products. It is not influenced household chemicals, so the surface can be cleaned by any means. The disadvantages of solvent-based varnishes include a long drying time (about 24 hours) and the ability to change the color of the wood - after processing the material becomes yellowish. The most common alkyd varnishes are GF-166 and GF-177.
The basis of the composition is alkyd glyphthalic resin, modified with natural oils, with the addition of an organic solvent and substances that accelerate drying. Forms a transparent glossy film on the surface of products; drying time for one layer is 48 hours.
The composition and main characteristics of the varnish are identical to GF-166, but have a shorter drying time and require careful preparation for work.
This type of composition is produced on the basis of an aqueous dispersion (for example, acrylic) with a small amount solvent. Thanks to this, they do not have a pungent odor and do not emit toxic fumes, and work can be carried out even in indoors. Water-based varnishes differ great variety color palette and can give the material any chosen shade without masking the unique structure of the wood. Surfaces treated with such compounds are not susceptible to fungi, mold and microorganisms and have an attractive appearance.
Lucky on water based are divided into two types: they can contain only acrylic (one-component compositions) or acrylic with polyurethane (two-component compositions). Two-component acrylic-based coatings have improved performance properties and are not susceptible to negative environmental conditions.
| Varnish type | Compound | Average drying time | Strength |
|---|---|---|---|
| Oil | Oil and resin, and an increased amount of resin promotes rapid drying of the composition, but reduces the strength of the coating | 24-72 hours | High |
| Yacht (alkyd-urethane) | Alkyd resins, organic solvent, urethanes | 2-4 hours | Very high |
| Polyurethane | Base with hardener (two-component composition), base with hardener and solvent (three-component) | 4-12 hours | Very high |
| Alkyd | Alkyd resins, solvents (white spirit, solvent), substances that accelerate drying | Up to 48 hours | High |
| Water | Liquid polymer (acrylic dispersion), antiseptic, plasticizer | 24 hours, but it takes 10-14 days for the film to form | Average |
Important: alcohol compounds and nitro varnishes are not recommended for outdoor use. Alcohol-based varnishes are suitable exclusively for restoration and carpentry work, while nitro varnishes are characterized by low water resistance and are quickly destroyed when exposed to ultraviolet radiation.
The most popular manufacturers of paints and varnishes include the following companies:
Wood varnish
Correct application of varnish is the key to reliability and durability finishing coating. The main point that needs to be taken into account before applying the work is that paint and varnish materials have some features and application conditions.
The remaining varnish can be poured into small bottles or jars (so that as little air as possible remains between the surface of the substance and the edge of the container), close tightly and place in a dark place, temperature from 5 to 30 degrees. Under such conditions, the composition can be stored for about a year.
To correctly determine the amount of paint and varnish mixture that will be needed for processing certain area surface, you need to know the varnish consumption per square meter. This setting depends on technical characteristics material and composition itself.
On average, the consumption of paint and varnish mixture when applying the first layer is a liter per 8-10 square meters, and when applying subsequent layers - a liter per 10-12 square meters. m.
Varnish is applied using different instruments, preferably with a brush, roller or spray. Not only the consumption of the composition, as mentioned above, but also the quality of the coating depends on the choice of tool.
The cheapest, most common and affordable option. Most often in stores you can find brushes with natural, mixed or artificial bristles. Natural brushes are best suited for oil-based paints, but when working, you should squeeze out the bristles well - they have the ability to pick up and hold varnish, so drips and unevenness may form on the treated surface. Synthetic brushes provide a smooth surface and are practically not subject to wear. Mixed bristles combine the advantages of natural and synthetic bristles, and the brushes are ideal for outdoor use.
The tool is convenient for processing large areas: fences, facades, etc. Rollers for applying varnish are distinguished by the characteristics of the working surface of the tool, length of pile and size. Long pile can be deformed during operation, as a result of which the quality of the coating decreases. Large rollers reduce the processing time of products, but are inferior in terms of convenience, since small ones create a more uniform and dense film. The best option for outdoor work - a medium-sized tool with long, reinforced bristles.
A spray gun or spray gun is the most handy tool for painting fences and facades, since with its help you can easily treat hard-to-reach places. Spraying makes it possible to create a high-quality, smooth and uniform coating. Spray guns can have different tank volumes, engine power and performance - the higher these characteristics, the more expensive the unit, but it will work budget models not very convenient, as they quickly overheat and turn off.
Spray gun
For better adhesion of paints and varnishes and of proper quality future coating, the surface should be well treated. If you apply the composition to unprepared wood, the coating will quickly lose its attractive appearance, crack and peel off.
The old coating (if any) must be removed with sandpaper, a spatula or construction hairdryer down to a clean solid base.
If there are cracks or crevices in the wood, they must be removed using a special putty.
Clean the surface of the product from dust, small debris and sand it sandpaper. If there are stains of grease or resin, sanding should be done along the grain - thanks to this, small fibers will not pick up, and the wood will become as smooth as possible. Before further processing, the surface must dry thoroughly.
Some craftsmen do not consider priming, or coating lumber with special compounds, to be a mandatory processing step, but there are several objective reasons for their use:
The primer composition is selected depending on the characteristics of the material and the composition for the final coating. Alkyd primer well emphasizes the structure of wood and increases its wear resistance, water-dispersed compositions do not have a strong odor and are non-toxic, and shellac primers are recommended for coating poorly dried and damp wood
When choosing a primer taking into account the characteristics of the finishing coating, you need to take into account that for polyurethane-based paintwork materials, it is recommended to choose compositions containing a solvent. When using water-dispersed paints and varnishes, it is best to use an acrylic or water-based primer. For outdoor work, it is recommended to choose formulations that additionally contain components that prevent the appearance of rot, mildew and mold.
You can begin applying the compositions after preparation (the process is described above) and thorough drying of the surface.
Step 1. Prepare the composition (dilute according to the instructions) and mix it well. Pour it into a suitable container wide enough to dip your brush into.
Step 2. Apply the solution to the surface in an even layer, brushing or rolling along the wood grain. When processing a facade or fence, pay special attention to the lower part, as it is most susceptible to moisture.
Step 3. Wait until the first coat of primer dries well.
Step 4. Clean the dried layer with sandpaper; if the surface is uneven, use wood putty. Remove dust from the wood that has formed after sanding.
Step 5. Apply another 1-2 layers on top of the first layer, each of them should be allowed to dry thoroughly.
After the primer has dried, proceed to finishing– coating the product with a varnish mixture.
Impregnation for wood
Before applying varnish to wood, it is recommended to carry out an adhesion test. Cover with composition small area prepared surface, apply the composition, and after 2-3 days try to remove it with a coin or spatula. If the coating is difficult to remove, it means that the varnish has bonded well with the base. If a coin or spatula leaves clearly visible, deep marks, it is necessary to treat the surface again or choose a different varnish.
It is best to apply varnish to a horizontal surface, so if possible, the product should be placed vertically - for example, when processing doors, remove them from their hinges and place them on trestles.
Step 1. Prepare the composition (if necessary, dilute it with water or white spirit), mix well, pour into a suitable container.
Step 2. Apply the first coat of varnish to the wood. Apply the mixture onto a tool (brush, roller) and squeeze lightly to avoid drips. On horizontal surfaces the varnish is applied in stripes, and on vertical surfaces - in cross movements, uniform and smooth. Some compositions (for example, acrylic) set almost immediately, so you need to work quickly enough so that no brush marks remain on the surface. The varnish needs to be rubbed well and ensure that no bubbles appear on the surface - they can be removed by brushing along the grain of the wood. Special attention pay attention when working hard to reach places and corners.
Step 3. After applying the first layer, it should be allowed to dry. The drying time of the varnish differs for each type of composition: in the case of water-based paints and varnishes it ranges from 1 to 12 hours, for alkyd and polyurethane mixtures - 24 hours, so it is better to clarify it in the instructions for the product.
Step 4. Once the initial coating has dried, it is best to sand it with fine-grained sandpaper - this way the second layer of varnish will adhere well to the first.
Step 5. Apply a second layer of the compound, this time undiluted, and let dry.
Step 6. Evaluate the treated surface in good lighting, if necessary, apply another 1-2 layers of varnish.
When using high-quality compounds and correct application, two layers of varnish are usually sufficient for a good surface finish.
Tinted varnishes are usually used to cover inexpensive types of wood. When processing, you can solve two problems at once: protect the material from damage and negative factors, and also “ennoble” it appearance. The technology for applying such compositions is no different from applying conventional ones, but has a number of nuances.
Sheathing with imitation timber: step-by-step instructions Wood sealant
All photos from the article
If you need to protect wooden structures located in the open air, you cannot do without special compounds. At the same time, compositions for outdoor use differ from those used indoors, so it is important to understand their varieties and the main features of each option.
This is what this review will focus on.
This option has several main differences:
The main types of such varnishes are the following:
Another large group of products, which is also used quite often.
This option has its own differences:
Without a doubt, this is the most popular and sought after option today.
This group of compounds has a number of undeniable advantages:
Advice! There are other options: alkyd, alkyd-urethane, etc. - they all have their own characteristics, which are indicated on the label. Therefore, please read the information provided carefully.
Choose high-quality composition is very important, since not only the appearance of wood products, but also their durability depends on this. The video in this article will tell you useful information regarding the topic discussed ().
For exterior woodwork, a special frost-resistant varnish must be used. This composition can be used for decorative design and protection of wooden products that are located on the street.
Exterior varnish will extend the life of wooden surfacesIN winter time wood structures can be significantly affected negative temperature, which worsens the performance properties of the surface. For example, if moisture penetrates into the structure of a tree in winter, then when it freezes, the liquid can expand and lead to the destruction of the coating. Therefore, any frost-resistant varnish used for exterior work must have pronounced water-repellent properties.
Today, frost-resistant paint and varnish compositions are actively used for painting the following wooden surfaces:
All these surfaces need not only protection from moisture, ultraviolet radiation, mold and fungi, but also from exposure to extremely low temperatures.
Today the choice of varnishes is large, the main thing is not to make a mistake, and for this you need to know a number of criteria, which are given below Today there is big choice paint and varnish coatings for exterior use. Basically, all of them do not affect the natural wood texture and do not change the shade of the surface. Modern materials with a frost-resistant effect they can have an oil, water and organic base. Any of these compositions forms an elastic film after drying, which increases the resistance of the surface to mechanical impact at low temperatures.
In addition, paint and varnish material for external use contains various chemical additives that protect the coating from fungal attack, ultraviolet radiation, cracking and discoloration.
Key characteristics on which the effectiveness of frost-resistant coating depends:
The main types of frost-resistant varnishes depending on the composition:
Yacht varnish is frost-resistant, wear-resistant and highly durable Types depending on purpose:
Popular paint and varnish compositions are solvent-based coatings. The composition hardens after complete evaporation of the solvent. As a result, a high-strength film is formed. This frost-resistant varnish is ideal for outdoor use, as it is resistant to abrasion and the chemical effects of detergents. However, solvent-based coatings can change the color of the wood surface, adding yellow tones.
Frost-resistant varnish with a water-soluble base is not as resistant to abrasion. At the same time, such material is considered more environmentally friendly. In addition, water-based material dries faster than all others.
The most durable varnish is considered to be one created on an alkyd-polyurethane base. He has excellent performance characteristics. A feature of oil-based paints and varnishes based on natural resins is that they can change the color of a country floor or other wooden surface, making it darker.
Today, woodworking has become popular for outdoor work. This paint and varnish material has all the necessary qualities in terms of elasticity and durability that are required for such compositions. It has increased frost resistance, as well as pronounced water-repellent and dirt-repellent characteristics. In addition, frost-resistant varnish of this type is applied without any problems and does not leave smudges.
Frost-resistant varnish should only be used after the surface has been coated with impregnation. Paintwork It is recommended to apply in 2 or 3 layers. All work must be carried out at a positive temperature. Paint material can be applied using a regular brush, roller or pneumatic sprayer. If you are going to work with a sprayer, then it is best to dilute the paint and varnish composition. The solvent used must match the composition of the varnish.
Before applying each subsequent layer, wooden surface needs to be sanded to improve its adhesion. At the same time, the next layer should be applied no earlier than four hours after painting.
Thus, frost-resistant varnish is very effective for outdoor woodwork. It allows you to protect the wooden surface from the negative effects of low temperatures and other adverse environmental influences.
