Alkyd paint: material characteristics

Gusevsky Andrey Anatolyevich

Alkyd paint on wood, metal, and plastered surfaces

In terms of component composition and structure, oil and alkyd paints have much in common, since both are made from oils. It’s just that in oil paints it is a natural drying oil, and in alkyd paints it is a modified drying oil, obtained by heat treatment of oils with alcohol and acid.

Alkyd based paints have many advantages over their opponents. They are applied easier and dry faster, and the paint film lasts much longer - so their higher price is justified.

Having called for help the video in this article, we will tell in detail about their properties, characteristics, applications, as well as the compatibility of alkyd paints and enamels with other types of substrates and decorative coatings.

Scope of paints of alkyd type

Due to the presence of organic substances in the composition, alkyd-oil paint is characterized by the best adhesion to the base - even if it is a smooth metal. In addition, it performs not only protective functions, but is also able to suspend the corrosion process that began at the base. This is especially true for metal with traces of rust, which can be coated with alkyd paint-primer without cleaning the surface.

So:

• There are options specifically oriented for metal work (seeHow is metal painting performed?), which are used in everyday life for painting galvanized roofs, fences, gutters, communication pipes and radiators. Some compounds are designed for woodwork, and can be used for painting carpentry, plank claddings, surfaces of timber and log walls, exterior decoration of frame houses.

DIY fence painting

• Some compositions, one of which is presented in the photo at the beginning of the article, which are truly universal. They can be applied not only to metal and wooden surfaces (seeWhat paint is better to paint a tree: we make a choice), but also on plastered mineral substrates, which include various types of masonry, concrete screeds. In any case, the manufacturer’s instructions on the label clearly outline the scope of the paint, and you need to carefully read it.
• The only disadvantage of alkyd paints is their toxicity, which is why they are practically not used for interior decoration, preferring water-based paints. However, they are not able to provide the strength that is needed, for example, for flooring.

Two-component enamel primer with rust converter

• For painting wooden and concrete floors (seeHow to paint a concrete floor: make a choice) Alkyd-urethane paint is best suited. Thanks to the polyurethane resin introduced into its composition, a wear-resistant and durable glossy coating is obtained.

In enamel primers intended for painting metal, it also contains compounds called corrosion inhibitors, the presence of which slows down its corrosion. Antiseptic substances that provide biological protection to the material are usually added to wood paints.

Alkyd enamels and paints: distinctive features

Everyone knows that in a wide range of paints and varnishes there are such concepts as paint and enamel, but what exactly their difference is, no one really knows.Many people think that if the coating is matte, then it is paint, if glossy - then enamel. In fact this is not true.

• In both cases, it is pigmented white, or mass already tinted by the manufacturer in a specific color. It is either in a liquid state, or is a thick paste that needs to be brought to a working consistency immediately before use - and this is where their similarity ends.
• By the way, the answer to the question: “How to dissolve alkyd paint?”, Depends on its type - this information is usually indicated on a can of paint. We will talk about this further, but for now we will consider how the paint differs from enamel. First of all, this is the composition: alkyd paint is a film-forming substance diluted with an organic solvent.

Alkyd Pentaphthalic Enamel

• The composition of enamels is much more complicated. Firstly, not only drying oil, but, as in the case of urethane-alkyd enamel, polymer resins, and even aqueous dispersions can act as a film educator. Enamels also contain varnish, fluorides, metal oxides, and they have the best protective properties.
• Alkyd varnish, which is pentaphthalic and glyphthalic, is the main component of enamels. In accordance with the type of varnish, enamel is classified. In finishing work, PF enamels are more often used, since they create the most durable coatings.
• As for enamels, their main advantage is the drying speed, which is extremely important during installation. Therefore, to protect metal structures, pipelines, machine mechanisms, mainly glyphthalic enamels are used.

Alkyd white paint on glyptal basis

• Thanks to their quick drying, they are also great for interior work: painting windows (seeHow to paint plastic windows: do it right) and doors; skirting boards; wood cladding and wall panels; suspended ceiling from lining or drywall.

Note! In general, not only the polymerization rate of the coating, but also its hardness, as well as the degree of gloss, depend on the fat content of alkyd resins, and it is regulated by introducing desiccants into the composition. How much this or that type of paint dries is indicated on the label - but in any case, enamel coatings harden faster.

Batteries can also be beautiful.

Despite the strength of the film, its excellent resistance to temperature changes, and other atmospheric influences, alkyd paints are rarely used for painting facades. The reason for this is their low vapor permeability, which is very important when it comes to the outer walls of heated buildings. Here the advantage over silicate and siloxane paints.

Alkyd Emulsions

Since the use of alkyd paints for internal use is rather limited due to the toxic odor, manufacturers began to develop technologies to replace highly aromatic solvents with water. Some of them managed to create a water-based alkyd emulsion, which at the same time retains all the advantages of alkyd resins.

This is a new word in the manufacture of paints and varnishes, and the key factor that distinguishes alkyd emulsion, for example, from acrylic emulsion, is the mechanism for its production. Of course, solvents are also present in them, but in very small quantities, which significantly reduced the toxicity of the paint.

Option for painting the interior of a timber house

However, due to a decrease in the organic component, the water-repellent abilities inherent in ordinary alkyd paints and enamels are significantly reduced, and yet testing has shown that these indicators are still better for alkyd emulsions than for acrylic dispersions.

Material benefits

In fairness, I must say that water-dispersion paints, which include alkyd emulsion, are poorly flowing.Conventional oil and alkyd paints have a higher viscosity, which increases with solvent evaporation.

• However, this process is reversible, and when applying the second layer of paint, the solvent in it interacts with the first polymerizing layer. Thus, its defects are easily corrected, which allows you to get a beautiful smooth film.
• When applying water-soluble paints, a sharp set of viscosity occurs during the evaporation of water. In this case, the polymer particles form fractions that cannot be dissolved by water, and the defects resulting from the application of the first layer can no longer be modified. Traces from the brush almost always remain, therefore it is better to apply water-soluble paints with a spray gun.

The beauty of a wooden floor with stains based on alkyd emulsions

• But since alkyd emulsions still contain a small amount of organic solvents, they are devoid of this drawback inherent in other water-soluble paints. They have good fluidity and the ability to align themselves, which not only makes it possible to obtain a uniform smooth film, but also provides it with brightness and a high degree of gloss.
• Manufacturers pay special attention to the decoration of natural wood, which could not hide, but rather emphasize the advantages given to it by nature. Alkyd emulsions make it possible not only to preserve the beauty of the tree, but also provide it with maximum biological protection.

Since the emulsion consists of substances of a very fine dispersion, it not only forms a film on the surface, but also penetrates deep into the structure of the tree, giving no chance to the fungi and woodworm bugs. Therefore, in addition to covering paints and enamels, impregnations and stains for wood are also made on the basis of alkyd emulsions.

Work with alkyd paints

So, we found out that the properties of oil and alkyd paints are determined by their main component - this is oil, and mainly linseed. In oil paints it is in its natural state, and in alkyd paints it is modified. Therefore, the answer to the question of how paint coatings of this type are diluted lies on the surface.

Note! If it is a thick-grated paint, that is, it has a pasty consistency, then it is simply diluted with drying oil. To dilute thickened enamel, you need to use white spirit, since other organic additives are also present in it. But the removal of the old alkyd coating, you need to use special washes.

Alkyd paint wash

The process of polymerization and hardening of the film occurs due to the addition of a catalytic effect, as well as exposure to warm, oxygenated air. Low temperatures and dampness not only slow down the drying and hardening of the paint, but also significantly degrade the quality of the coating.

The film shrinks under such conditions, ripples appear on its surface. Therefore, it is so important that the air humidity when working with alkyd paint is normal, and the ambient temperature when performing and drying the coating does not fall below +5 degrees.

In summer, alkyd paints dry for a day or a little more, which depends on the number and thickness of the layers. Enamels take no more than 6 hours to dry each layer.

What to consider when applying

To apply an alkyd coating, as, however, and any other, should be on a dry primed base. It is only important that the primer is made on the basis of the same substance as the paint. That is, if gliftal enamel, then the primer should be labeled as GF.

By the way, not only paints, but also alkyd-based primers can be water-borne - that is why they must be selected to each other.

So:

• Alkyd soils are most often pigmented.therefore perfectly cover the base surface and create an ideal base for applying a decorative coating.This is especially important when the work is carried out on highly absorbent substrates, which include wood and sheet materials from it, gypsum screeds, some types of wallpaper for painting.

Waterborne Alkyd Primer

• In principle, you can not even buy soil separately. Make it yourself, using the same paint, only diluted to a more liquid state - and than to dilute the alkyd paint, we have already said. This approach will be technologically correct, since in the first layer, due to which the absorption of the base is reduced, there should be less binder than in the subsequent one.
• Alkyd type paints can be applied not only to wood, metal, plastic and concrete, but also on enamel, as well as on old paintwork oil, polyvinyl acetate, butadiene, and polyurethane coatings. The main thing is that they hold well on the base, otherwise, the old paint needs to be washed off.

Primed painting

• When working with alkyd paints, you need to remember that they can not be applied to fresh cement plaster, or a recently poured concrete structure, since they still retain an alkaline reaction. In this case, it is first neutralized with fluorosilicate, and then, after drying and priming, coloring is performed.

Alkyd paints and enamels can be applied both manually and by means of a spray gun. Only in the second case, it is better to use a low-pressure apparatus, which does not create fog from spray paint. It should be remembered that its consistency, when applied with a spray gun, should be more liquid.