Composition and properties of the anti-corrosion primer, rules of use

To improve the adhesion of the paint to the surface, as well as to protect the painted material from adverse factors, various types of anti-corrosion primer are used. It is only after a preliminary primer that the coloring composition or varnish can be applied to give gloss. It is important to choose a high-quality floor, use it in accordance with the technology, otherwise there will be a risk of destruction of the decorative coating, corrosion.

Anti-corrosion primer: composition and properties of the material

The anti-corrosion composition comprises:

• components for improving grip;
• solvent;
• varnish;
• a substance for hardening the applied composition;
• pigment, usually gray.

Anti-corrosion primer is moderately consumed, hardens quickly, provides good adhesion, is not sensitive to temperature conditions. The main property of the coating is the prevention of corrosion.

After application, a high-quality primer remains resistant to temperature fluctuations in a wide range, it is also waterproof, elastic, so you should not be afraid of cracking the upper decorative coating. It is evenly distributed over the surface, seeping into the smallest cracks and additionally protects against fungal infections.

Mechanism of application and protection against corrosion

Anti-corrosion primer is mainly used to protect metal from rust. Most often, large areas are covered with the composition, for example, the body of cars. The primer blocks the oxidation process that occurs when the metal surface comes into contact with moisture and oxygen.

Additional functions:

• increase the adhesive ability of the paint;
• alignment of the painted surface;
• removal of scratches and other surface defects;
• extend the life of a metal product;
• preventing the topcoat from cracking.

Primer is used both as an independent protective coating for metal, and as a substrate for painting or decorating with varnish. They can protect weld areas or other connections of metallic elements.

The primer applied to the surface is transformed into a dense film that does not pass water and air molecules. Its thickness - about 50 microns - is sufficient to reduce the number of layers applied.

Advantages and disadvantages of soil

An anti-corrosion primer has many advantages:

• reliably protects against corrosion;
• dries quickly;
• moderately consumed;
• provides good adhesion - adhesion of paint to material;
• does not smell strong;
• evens the metal surface;
• eliminates minor hardware defects.

When choosing an anti-corrosion primer, it is necessary to take into account its inherent disadvantages:

• use for metal only;
• the need for prior surface preparation;
• mandatory use of personal protective equipment and the presence of ventilation due to the content of toxic components in the composition;
• gradual decrease in the effectiveness of the protective coating, the need for re-application.

What are and how to choose an anti-corrosion primer for metal

According to the principle of action, anticorrosive soils are distinguished:

• The primer, also called primer, is a metal protector against corrosion, an adhesion activator. Apply in a thin layer without sanding.
• Secondary, also known as filler, is a surface leveling agent before applying a decorative coating. Eliminates scratches, creases.

In terms of composition, soil is:

• Monocomponent. It is implemented in a ready-to-use form.
• Two-component. It is a base compound applied in a dense coat to bare metal or putty surfaces. It is necessary to add a hardener to it before use.

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Based on the components, the anti-corrosion primer is:

• Alkyd. A versatile and sought-after look. The zinc phosphate in the formulation provides an excellent anti-corrosion effect. The primer dries quickly and is not sensitive to significant temperature increases.
• Epoxy. The active ingredient it contains is iron oxide. The thin film formed after drying is elastic, moisture resistant, absolutely waterproof.
• Polyurethane. In terms of the principle of protection, it does not differ from the previous primer, but it is only suitable for application on a perfectly even product.There is a variety of this floor with a filler in the form of crushed polyurethane; before using such a composition, you do not need to thoroughly clean the surface.

When priming a car to protect it from corrosion, it is permissible to apply the composition not only to the metal itself, but also to adjacent plastic parts, where rust is most likely at the level gaskets.

According to the effect on the material, the floor is:

• Engraving. It divides the structure of the surface layer of the metal, making the surface more convenient for painting.
• Firming. It forms an impermeable film that prevents the metal from undergoing oxidation.
• Actually anti-corrosion. Protects against rust.

Ranking of the best brands

There are many manufacturers of anti-corrosion primers, among which there are many worthy and proven companies:

• Tikkurilla is a quality product from a Finnish manufacturer that can safely be placed at the top of the list.
• German brand Ceresit.
• Russian brand KUDO.
• Russian manufacturer VGT.
• Yaroslavl Paints and Varnishes Factory.

Subtleties of use

Before applying the anti-corrosion primer, the surface must be prepared in a special way. Thoroughly mix the primer until smooth, if necessary pour in a solvent to reduce viscosity and prevent premature solidification in the working container. Failure to do so will result in uneven primer deposit, peeling or blistering of the paint after drying.

Surface preparation for primer

Before applying the primer, the surface should be cleaned of old stains of paint and rust, go over it with emery paper or a metal bristle brush. If the old paint is not scraped off, you can go over it with a construction hair dryer and then scrape it off again.

The dust particles remaining after cleaning must be blown out by a compressor unit. The surface must remain perfectly clean. The preparation of the metal is completed by degreasing. To remove greasy stains, the following are optimal: industrial alcohol, gasoline, thinner.

Tools required

You can apply the primer with any handy tool. For large flat surfaces, a paint roller or a wide paintbrush of about 10 cm is optimal. If the metal surface exceeds 2 m², it is better to use a spray gun. And for small rooms, corners, narrow pipes, a brush up to 5 cm wide is suitable. Primer in spray cans is universal.

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Calculation of consumption and preparation of the working solution

The most common anti-corrosion primer comes as a thick liquid in plastic buckets. The one-component anti-corrosion primer contains only a 5:1 thinner. In a two-component primer, add the hardener first in a 4:1 ratio, then the thinner.

This form of anti-corrosion primer is not very practical to use. Therefore, an aerosol primer sold in cans is becoming increasingly popular.

The aerosol primer is ready to use, just shake the can. The composition is easy to apply, does not require special tools, forms a smoother layer, ideally masks minor surface defects.

What will be the thickness of the layer, what will be the consumption of the soil, depends on the method of application:

• when working with a brush, the primer is heavily consumed, per 1 m² requires 300-400 g;
• when using a paint roller, 250 g is enough;
• working with a gun, you can reduce consumption to 150 g.

The above values ​​​​are relevant for a soil layer with a thickness of 40-50 microns.

Application of a primer coat

As the anti-corrosion primer forms a dense film, 2 to 3 treatments are generally sufficient. If the first layer is applied with a roller or brush, then the last is best done with a spray gun, it will be more accurate.

Apply an anti-corrosion primer to two types of surfaces:

• On bare metal. A primer coat is necessary, as the metal surface has little adhesion compared to paints and varnishes. Without a primer, the paint will simply peel off.
• On the putty. In this case, the anti-corrosion primer is applied first, followed by a specific primer for paint adhesion. It is impossible to paint over the anti-corrosion layer, the paint will begin to bubble.

It is necessary to work with soil outdoors on a clear day when there is no rain, strong wind, heat or frost. The optimum air humidity is 80%.

Metal can only be painted after the primer is completely dry. Otherwise, paint consumption will increase or the finish will be uneven.

Drying time

Each manufacturer creates a primer with an original composition that affects the speed of drying of the coating. Typically, the anti-corrosion primer dries completely in 12 hours at a temperature of about +20 ° C.

The amount of dry anti-corrosion primer from a specific manufacturer is indicated on the label. It also contains instructions for the correct operation of the composition.

To speed up the drying of the floor, you can use special devices: heat up to + 60 ° C with a heat gun or turn on the infrared lamp at a distance of at least 0.7 m from the covered surface so that the layer of primer does not bubble.

Another option is to purchase an anti-corrosion compound with components for accelerated drying. Some primers dry so quickly that paint and varnish can be safely applied after 10-15 minutes.

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Precautions and safety measures

Before using the primer, you should carefully read the instructions so as not to spoil the work. Be sure to use personal protective equipment: respirator, construction goggles, rubber gloves.

Before starting work, cover the surfaces adjacent to the area to be painted with polyethylene, masking tape or a thick cloth so that they do not get dirty. If a primer is planned for the car, then you need to protect the headlights, windows, mirrors and wheels.

Allowed errors and additional recommendations

To achieve a high-quality result, you need to follow all the recommendations for the primer, take into account all the nuances of the work.There are several requirements that apply to almost any type of floor:

• cannot be primed outdoors in freezing, rainy and foggy weather;
• the final decorative coating must be compatible with the primer, preferably of the same brand as the latter;
• after application of an anti-corrosion alkyd primer, the final coating can be omitted, as this composition is resistant to external influences;
• the areas most sensitive to stress, it is advisable to treat the floors with automotive sprays;
• the primer should be diluted in the amount necessary for work, it should not be left for several days, otherwise it will lose its quality characteristics;
• not the slightest untreated area should remain on the metal surface, otherwise it is from this place that rust will begin to spread.

Storage rules

In most cases, the shelf life of primers indicated by the manufacturer is 18 months, but it all depends on the specific brand and composition. Some manufacturers sell floors with a longer storage period, up to 2 years or even more.

This shelf life is only possible if the soil is stored in the right conditions. But the date indicated on the label does not mean that after this time the composition will instantly lose its working properties. The expiration date only indicates that during this time the soil will be stored without losing the quality characteristics declared by the manufacturer. And then the quality will gradually deteriorate. Therefore, for some time after the expiration date, the primer can still be used.

In order for the anti-corrosion primer to remain suitable for longer, the following storage rules must be observed:

• not to violate the tightness of the factory container so that the composition does not change under the influence of external factors;
• during use, do not pour the primer into another container;
• do not store the composition where it can freeze or overheat.

When expired soil becomes unusable, you can tell by its appearance. Signs of a composition that has lost quality:

• heterogeneity, clot formation, lumps;
• tighten the soil with a film;
• the appearance on the surface of spots, spots;
• strong thickening;
• separation into layers - liquid at the top, solid particles falling at the bottom;
• an unpleasant, pungent smell, reminiscent of a swamp or a muddy puddle.

Expired primer should not be used. It must be recycled. Its quality characteristics - drying time, protective and adhesive properties - no longer meet the standards of these products.