The subtleties of choosing oil paints

Among the many types of coloring compositions actively used in Russia, oil paints are invariably present. But even the long history of their use does not allow most people to consider their knowledge about these dyes complete. Meanwhile, behind the general name of the group hides a number of original technological solutions. Only knowing the exact features and specifics of marking, you can understand the range of paints and varnishes and make the right choice.

Oil paint, or drying oil, is always made from oils, in most cases from linseed and hemp, sometimes from castor. They do not differ in a high evaporation rate, and some species do not form volatile compounds at all at room temperature. Exactly because of this reason oil paints - both for indoor and outdoor use, characterized by a very long drying period... A layer of oil that occupies only tenths of a millimeter on the surface of the coating can completely evaporate only after a few months.

As a result, any oil paint can only be applied in a thin layer; in order to further speed up the process, driers, that is, catalysts, are added to the drying oils, but even with such additives, drying will be completed in at least 24 hours. In accordance with GOST 1976, natural drying oils should consist of 97% of processed vegetable oils, the rest of the volume is occupied by driers, and other additives are not allowed at all.

Composition drying oils "Oksol" according to GOST 1978 is as follows: 55% are natural oils that have undergone oxidation, 40% is a solvent, and the rest is occupied by a desiccant. Its cost is less than that of natural brands, but the presence of white spirit in the recipe does not allow the mixture to be considered safe. The formation of combined drying oils occurs from the same basic substances, but the concentration of the solvent is reduced to 30% by volume. The formulation of alkyd mixtures includes resins of the same name - glyphthalic, pentaphthalic, xiphthalic. Synthetic preparations are 100% formed by waste from oil refining and other complex industries.

Pigments for oil paints are always used of inorganic nature. They are divided into those with a pronounced color and black and white. Achromatic dyes include, first of all, zinc white, which is very cheap, but turns yellow under the influence of high temperatures. White color in modern oil paints is often given with the help of titanium oxide or lipoton, which are much more resistant to heat. Black tone can be achieved by using carbon black or graphite. As for bright colors, they are created like this:

• Yellow iron metahydroxide, lead crown;
• Red lead red lead or iron oxide;
• Blue iron azure;
• Dark red - chromium oxides;
• Green - with the same chromium oxides or cobalt compounds.

Manganese, cobalt or lead salts are used as drying catalysts (driers); it is very important that the concentration of the desiccant is not excessive, otherwise the film will not be sufficiently stable.

The main characteristic of any oil paints is the concentration of the substances that form the film. They should be at least 26%, since the strength of the created coating and its ability to remain on the surface depend on this indicator. But it is important to take into account that the more the compositions are saturated with film-formers, the worse they are stored.

Everyone who has had experience with oil paints knows for sure that they have a strong odor, which is especially harsh when heated from 20 degrees and above. Therefore, the share of volatile substances in the norm should account for a maximum of 1/10 of the total volume. Further, it is worth considering such a parameter as the fractional composition of dyes.

How quickly an oil paint dries depends on its viscosity; this indicator also affects the fluidity and how easily and easily the substance is distributed over the surface. Normally, the viscosity is not lower than 65 and not higher than 140 points, deviations in both directions clearly indicate the low quality of the material. Mechanical strength and water resistance can also be considered an actual technical indicator.

Manufacturers of oil paints convey basic information to the consumer through labeling. First, there are letter combinations: MA - mixed or natural drying oil, GF - glyphthalic, PF - pentaphthalic, PE - polyester. The first number denotes the use in external and internal decoration, the second emphasize the type of binder, and the rest are assigned to the index assigned by a particular enterprise. So, "PF-115" should be read as "oil paint on a pentaphthalic base with the addition of natural drying oil for outdoor use, factory index 5". MA-21 means a mixture based on a combined drying oil for interior use. MA-25 and MA-22 are also similar to it.

BT-177 is an oil-bitumen paint that can be applied to a bitumen surface. According to the GOST applicable to such a composition, it must be completely ready for use. Regardless of the specific brand of oil paint, it is possible to apply enamel or other type of paint and varnish materials over it only with a smooth layer that does not have any external defects.

Artists also actively use oil paints, and for them the typical shortcomings of these materials, which builders constantly complain about, are not significant. If oil forms directly on the surface, the paint must be stirred before each use. Only by mixing a few tones can you get a truly original color. A quick-drying artistic paint is considered to be Neapolitan yellow based on white lead. Tempera dyes are similar in nature to oil dyes. Each artist chooses what suits him best.

But for builders and people doing repairs, of course, other properties are in the foreground. In many cases, it is very important that the painted surface is oil-resistant; this requirement is relevant in industry, energy, transport and some other industries. For pipelines and radiators, resistance to high temperatures will come first. By the way, the disadvantages of oil paints in such an area far exceed their advantagesand no specialist will recommend them unless absolutely necessary. You can create a matte surface by adding a solution of laundry soap (40%) to the paint, while initially all oil compositions are glossy.

When choosing oil paints, there is always a contradiction between price and quality. So, compositions based on natural drying oil are invariably more expensive than those containing a synthetic base.Titanium pigments always cost more money than plain zinc white. It should also be taken into account that paints produced in the nearest regions will be cheaper than exactly the same ones, but brought from afar, especially those that have overcome customs barriers.

Initially, oil paints were used specifically for decorating wood and cans traditionally indicate their consumption per 1 sq. m. wooden surface. It should be noted that only perfectly clean and even, smooth surfaces are suitable for the application of oil paint.

Oil paints for metal in most cases are made on the basis of natural drying oils. They are able to withstand heating up to 80 degrees, which does not allow the use of such compounds on roofs and heating devices, for painting metal heating radiators. In addition, the low durability of the coating makes it difficult to apply outdoors, on a wrought iron fence or other fencing, for example.

Painting plastic with oil paints is quite possible, but the result is ensured only if the surfaces are thoroughly prepared. In artistic glass painting, oil compositions are used very often, but since they create a matte surface, this must be taken into account. The coating will not be sufficiently heat-resistant, but thinning the topcoat will protect it from water ingress. On concrete and plaster, a layer of oil paint lays down no worse than on wood or metal. If you cannot understand the differences between different paints for application on certain surfaces, it is better to seek professional advice.

When you choose paint for wood, be guided by GOST 10503-71, compliance with it guarantees the quality of the coating. Wood floors will need to be repainted every three or four years to compensate for the rapid wear of the layer.

It doesn't matter what specific material the oil paint is intended for, you may be faced with the need to dilute the mixture. Over time, it thickens or even turns into a solid. The only acceptable dilution method is to add what is in the base of a certain paint.

When the jar is not too long, the addition of drying oil helps to make its contents less thick. But it is important to take into account that drying oil is prepared using various technologies, and having made the wrong choice, you will ruin the entire product. And after a strong compaction (drying), you will have to use a solvent. With its help, you can make a primer from paint.

Natural linseed oil in the base of oil paints can be diluted only with natural compounds. And composite mixtures are required to be diluted:

• Turpentine;
• White spirit;
• Solvent;
• Gasoline.

First, the paint and varnish composition is moved into a container, where it can be interfered with and broken up clots. Then gradually add drying oil and immediately mix thoroughly. When the desired consistency is reached, the paint must be passed through a sieve, which retains small lumps.

When choosing a solvent, keep in mind that certain types of it can distort the physical and chemical properties of paints... Like drying oil, the solvent is added in small portions to maintain the basic ratio of the components. Simple white spirit will not work, you need to use only refined, which liquefies better. Turpentine that has not been purified can also not be taken - it delays the drying of the painted layer.Kerosene has the same effect, so it is used when nothing else can be used.

The cost of oil paint indicated on the labels is always average, designed only to estimate the volume of the material or reflect the coverage and the value of the dry residue. But it is important to know all the factors that affect the actual paint consumption. The base figure per 1 m2 is from 110 to 130 g, but the specificity of the base (the material that is painted) is not taken into account here. For wood, the normal range of values ​​is from 0.075 to 0.13 kg per 1 sq. m. When calculating, the following are taken into account:

• Breed;
• Heating and relative humidity;
• Surface quality (how smooth and smooth it is);
• There is a preliminary layer or not;
• How thick the tone is and what color you want to form.

For the calculation to be accurate, you need to pay attention to the type of metal or alloy, the general condition of the surface layer (primarily corrosion), and the use of a primer. The consumption of oil paints on concrete is determined primarily by how porous the surface is against the wall, floor or ceiling. For 1 sq. m sometimes you have to spend up to 250 g of the coloring composition. Simple plaster can be painted at the rate of 130 g / sq. m, but the embossed and decorative varieties are much more difficult in this regard.

The most consumed tone of oil paint is yellow, a liter is never enough for more than 10 square meters. m, and sometimes it is possible to paint half as much. Slightly better performance in white, although the ceiling is the same. A liter of the dye mixture allows you to create from 11 to 14 m2 of a green wall, from 13 to 16 of a brown wall, or from 12 to 16 of a blue one. And the most economical will be black paint, its minimum indicator is 17 m2, the maximum is 20 m2.

The general conclusion is simple: light oil formulations are spent more than dark ones. When there is already a layer of paint underneath, more material will have to be used. Sometimes it is more profitable to clear the base and prepare the plaster or ground layer, this will simplify the subsequent work. Of course, when painting in 2 coats, you will have to increase the standard consumption figures by 100%.

Much depends on the tool used. Using brushes, you will inevitably spray paint, it will drip onto the floor and accumulate on the pile. Determining the thickness of the layers becomes more complicated, as a result - more material will have to be consumed, and the likelihood that the work will have to be redone is quite high. The most economical among hand tools, perhaps, are rollers with silicone nap. And if we consider all the options, then the best solution is to use a spray gun. Extremely accurate numbers can be obtained using online calculators.

Approximate calculations refer only to a flat surface, painting pipes or other structures of complex shapes requires additional calculation of paint consumption. When work is done outdoors on a sunny windy day, the cost of oil paint is 1/5 higher than painting indoors at room temperature. The drier and quieter the weather, the better the coverage will be.

Although oil paint is not considered to be the most perfect, it is still produced by various manufacturers. First of all, you need to make a choice between Russian and foreign products: the first is cheaper, and the second is more prestigious, and modern technologies are used earlier in its production.

Consumers in corporation product reviews AkzoNobel note the high quality, the ability to endure up to 2 thousand cleanings. And adherents of the Finnish Tikurilla it is often chosen because this brand produces over 500 shades.

For an overview of Tikurilla oil paint, see the following video.

If you do not want to prepare the mixture, but immediately apply it, buy liquid formulations; unlike thickly grated, they only need to be mixed until completely homogeneous.To paint a tree, it is better to take the maximum amount and still leave a margin for tinting and rework.