Powder coating of metal products - do-it-yourself painting technology. How to paint metal without unnecessary difficulties? Metal coloring

Painting metal products is a fairly common thing. After all appearance has quite great importance. But here it should be understood that every metal is painted differently. Yes, and dyes are also used not the same.

Today we will tell you how metal painting is done, which dye is better to use and how to do it all yourself. Also on the video and photo you can find additional and necessary information.

Recommended for use with oil-based paint. But now the twenty-first century and therefore, there is big choice many other options are better, you can even paint with acrylic paints and those that are diluted with water, or others from various compositions.

Attention: The main thing to consider is that the paint contains rust additives, and preferably those that create a dense coating. These types of paints are more expensive, but they are durable, which is much better. And over time, such paint does not change, because it is elastic.

If you choose the right paint for a certain type of metal, then the end result will be perfect. metal parts in the most common cases, they are made of "black iron". This steel is covered with rust in a short time and it must be painted without fail. Mainly used for this oil paints.

Attention: To better protect the surface, it is necessary to use a primer with a high content of zinc compounds.

Before the advent of roofing material, galvanized sheets were used to cover roofs because they resist rust much better. This roof covering option lasts up to fifteen or more years, and if you also paint (see How to paint a galvanized roof: choose and do it right), the service life will only increase.

And the roof will be more beautiful and useful:

• Non-ferrous metals are rarely dyed. Because according to the rules they need to be covered with varnish liquids, and not painted.
• You can buy varnishes, which are characterized by multifunctionality and versatility of application. Do not forget to read the instructions that come with each paint. It is written about all the nuances and rules of application.
• We also pay attention to where the painted part will be located.. If it is a street, then you need to purchase a dye for exterior surfaces. If indoors, then a dye for interior surfaces is suitable.
• If the dye will be heated, then you should pay attention to alkyd and oil paints. They can withstand temperatures up to 80 degrees. And if you're painting sheet metal on the roof, then this option is completely suitable. It will withstand the heat from the sun. Also, these dyes are suitable for painting heating radiators.
• If the heat is higher, then heat-resistant dyes are suitable for you..

Paint application process

First of all, you need to prepare workplace. If the paint can spoil the parts that will not be stained, then we cover them with paper or cellophane.

If painting is done on metal structures at a height, then we prepare the place. Lead you will have to move freely. Painting of metal structures snip involves next order conducting work.

Preparing metal for painting

How to paint metal correctly now we will consider in detail. The dye should last for a long time and just this depends on the quality of the preparation of the base plane. To do this, the plane must be completely cleaned of excess, including rust.

• First you need to clean the debris from the coating. Then you should clean the corrosion and falling paint (see How to wash off the paint without problems), it is more convenient to do this with a scraper, sandpaper or iron sponge. Wash dirty stains and grease, as well as other contaminants from dust.
• Not recommended for use chemicals, it is better to take ordinary soap. Then wash with normal clean water and leave to dry. If you need to paint some large and massive object, then it is better to use a special burner. From the fire of the burner, the paint will burn, and everything that is not needed will disappear due to corrosion products and the difference in the values ​​​​of thermal expansion of metals.
• As an option, you can use a corrosion converter, but this is already hopeless and advanced cases. This is a liquid made with the addition of phosphoric acid. The surface is smeared with this solution and left for a short time, most importantly at least three hours, then washed with water and dried.
• To remove dyes from sinks, a grinder with a metal brush is perfect. It will fit through any hole. But sometimes it can partially "lick" the dye. And the remnants will have to be removed by a grinder with an envious circle.

Attention: There are cases when the rust is not removed at all. Then you don’t need to be upset (if you don’t need to make a high-quality and perfectly even coating), but you can simply apply paint to the surface that you could achieve. But the paint must be with anti-corrosion additives.

Metal primer

After the surface is thoroughly cleaned, it is necessary to carry out priming. Primer, it's protection from environment and is also used as a corrosion converter. Also, priming creates good adhesion final cover.

Primers are different types. The instructions on the package will tell you how and why this composition is used.

• Primers with good adhesion are perfect for non-ferrous metals, and for black primers with anti-corrosion coating.
• Primer application methods are different.(pouring, roller, spraying, brushing and many others). Choose the one that suits you best.
• Before applying the primer, it is necessary to degrease the plane. Almost any solvent will work for this.

Attention: When priming, smudges should not be allowed. If they are, then the dye will repeat them.

Metal painting technology

Now consider how to paint the metal and apply the dye. First you need to test the paint on a small area, leave to dry. If it lies well and looks good, then you can continue the main staining process.

• If the surface is curved, it is recommended to use a brush. The more complex the surface, the thinner the paint layer should be. Basically, the paint is applied in two or three layers, if you reduce the thickness of the painting layer, then it is possible in five or six layers. Moreover, each subsequent layer is applied after the previous one has completely dried.
• The painting tool is essential. It has already been written above how it is recommended to choose the right paint tool.
• If the surface is small or needs to be touched up small plot, then a spray can is ideal. From it, the paint will be applied in a thin layer, it is recommended to apply only at a distance of about twenty centimeters. In this method of painting, there should be at least four layers. After each layer, you need to wait twenty minutes.

• The roller is best used when painting flat and large surfaces. When using a roller, you need to dilute the paint by ten percent with a thinner. The edges can be tinted with a brush. When painting with a roller, two or three coats are sufficient. · Ideally wait between two coats of paint to wait thirty minutes, but not more than three hours, otherwise the paint will harden. If the paint hardens, then you can’t paint further, it will be possible in about a month or two. The thickness of all layers must be more than one tenth of a millimeter.

If you want to apply a quality coating and give it a beautiful and modern look heed these tips.

What is powder coating

Powder coating is a dry finishing process. Appeared this species in America more than fifty years ago and as a result instantly spread throughout the globe.

This type of metal painting has become famous for its advantages. Items dyed using the dry finishing process are more durable and last longer, and therefore more beautiful.

Also powder coating used for protective purposes and in decorative trim, exists in a huge range of colors.

Advantages powder coating:

• Applied in one layer. This is an advantage, because liquid paints need to be applied more than two or three layers.
• Powder paint helps get rid of rust. Great for covering metal jewelry.
• The use of this paint is economical. The paint can be turned back into powder and used again. Also at home, you don’t need a professional for this, because painting is elementary. And another good factor is that no solvent is needed.
• Such paints do not need to be diluted, and they do not need to be brought to a certain viscosity. They can be used normally.
• Painting requires fewer helpers.
• The quality of such paint is better, the coverage for many years, and the surface with such paint has best properties in operation.
• Environmental friendliness, which is not unimportant. It does not contain harmful organic substances. The substance hardly ignites. The paint has no toxic odors.

How powder coating is applied

Powder coating under the metal is applied in three stages:

• Surface preparation. This is the most difficult and long process. It is not considered important, although the quality of the coating depends on it. This includes dirt removal and rust protection. Cleaning is possible chemical or mechanical.
• Application of powder paint. After the surface is cleaned, the object is placed in a special chamber in which powder paint is applied.
• The third final stage is polymerization. The paint is melted, it hardens and then cooled. Hardening takes place in a special oven.

Attention: In order for everything to turn out evenly, it is necessary to maintain a certain temperature in the oven.

• The surface is then cooled in air. And the painting is complete. The powder used for painting is made on the basis of polymer resins, with the addition of hardeners, various pigments and completely incomprehensible additives. All components are mixed, cooled and processed into a homogeneous powder, similar to flour.
• You can still apply the mixture using a special gun (sprayer). Paint particles pass through the gun, are charged with a charge and adhere to the surface to be painted (with the opposite charge). Be sure to degrease the surface before painting and still carry out chemical treatment.
• When powder paint is on the surface of the product to be painted, it is placed in a special oven where the paint particles are melted and hardened. When painting large objects, use special system. With its help, painted objects move from one stage to another without difficulty. They are served on a special gurney on rails or on a suspension. This system simplifies the painting process and improves productivity.

Attention: Powder dye is not so cheap to apply, but it is quite durable and the price is justified.

Now you know how to paint metal. There is also metallic paint, it is used for painting cars. But there is a separate article on this topic on our website, because its application is quite complicated.

Quality painting metal products implies a number of operations that are mandatory, since the quality as a whole depends on them.

Product pretreatment

The product to be painted must be properly prepared. Rust, dirt, old paint - all this should not be! It must be perfectly clean, only then it is suitable for further use.

Chemical degreasing

Proper painting of metal products with a powder suspension is impossible without degreasing. Even if there is no dirt or corrosion on the surface, it is necessary to carry out chemical degreasing and achieve perfect cleanliness.

Coloring

Direct painting begins with the fact that the object is placed in a specialized chamber where the powder is sprayed.

After that, the part with the applied paint moves to another chamber, where the paint is fixed (polymerized). Under the influence electric field the powder turns into a polymer film that penetrates even into the pores of the metal and covers it with an even layer.

Quality control

Good coloring of metal products is impossible without careful quality control. The part with paint cools down and with the help special device checking how even the layer was applied.

powder coating price

Base price

Aluminum profile painting

Painting of galvanized and sheet metal

Picket fence painting

Painting accessories and hardware

Prices for the manufacture of a picket fence

The cost of the service includes loading and unloading, standard surface preparation (degreasing), as well as packaging of painted products. In addition, the price of powder coating depends on the volume, specifics of the work, as well as on the features of the metal products themselves. The nature of the surface and area, weight and size, the need for additional processing and other factors.

In particular, the price in one direction or another is formed by such features as:

1. flat or corrugated surfaces;
2. flat or bulky products;
3. length of molded products (pipes, profiles, etc.);
4. configuration of small products (the price depends on its complexity);
5. urgency (urgent coloring is possible on the day of treatment).

The need also affects the cost. pre-treatment and preparation (cleaning of oxides, drilling of process holes, etc.). The extra charge is applied for urgent works, metallic, antique, wood grain, lacquer painting, as well as for painting in two colors (for example, car rims).

What influences the choice of powder coating

Paint based on polymer powder is characterized by several parameters:

• chemical composition (on a thermosetting and thermoplastic basis);
• type of film former (epoxy, polyester, polyvinyl chloride, polyethylene paints);
• appointment.

All three parameters determine where and what kind of paint is suitable for obtaining best result. For example:

• Epoxy paints - provide excellent adhesion to the metal surface mechanical strength and resistance to aggressive environments. They are a good dielectric. However, UV resistance is lower than other varieties. They are recommended for indoor use. Apart from decorative effect they provide metal products with reliable anti-corrosion and chemical protection.
• Polyester paints - have high resistance to abrasion, precipitation and, unlike epoxy, to sunlight. However, unlike them, they are less resistant to alkalis and have lower dielectric values. Widely used for painting products that are outdoors under the influence of precipitation. They have a high decorative effect (gloss).
• Epoxy-polyester - they combine many of the advantages characteristic of epoxy and polyester paints: resistance to moisture, salt solutions, dilute acids and alkalis. Primary use - for products used indoors.

Areas of use

This dyeing method is used only for materials that are resistant to the temperature at which polymerization occurs. The lion's share of such products is precisely metal (made of steels, alloys, aluminum, cast iron, etc.) and their list is almost endless. Due to their characteristics and coloring results, powder coatings are widely used in various fields.

• Construction and Decoration Materials- doors, window profile, blinds, fences, gates, roofing materials And so on.
• Home Appliances — gas stoves, dishwashers, dryers, refrigerators, water heaters, washing machines etc.
• Metal furniture, plumbing, kitchen tables and chairs, office and warehouse racks, office partitions.
• Electrical equipment - electrical cabinets, transformers, motor and housing windings, junction boxes, connectors, etc.
• Transport and special equipment - cars (wheels, etc.), motorcycles, excavators, forklifts, etc.
• Sports equipment and more.

The company "Deline" provides in Moscow services for painting all of the above and other products using advanced Austrian Henkel technology. We not only guarantee the excellent quality of the result, but we give an extended warranty on the work.

18.07.2018

The modern offer of metal casting and metal rolling allows enterprises using these materials in their production activities to choose them desired color and forms. However, it often happens that in the process of manufacturing a particular design, it is necessary to adjust the configuration or color metal billet. This happens, for example, when a product is manufactured according to individual project. Today we will talk about one of the most common and popular technological operation in the field of metalworking - metal painting. It is used to give the finished part or structure the desired look and improve its operational properties:

• increased resistance to ultraviolet radiation and aggressive chemical substances(solvents, chemicals, etc.);
• resistance to mechanical stress and abrasion;
• improved resistance to humidity and temperature changes;
• providing protection for hidden edges and corners.

Preparation for painting metal

Depending on the specifications and features of the surface of the workpiece, as well as its purpose, apply various technologies colors and types of dyes. Before using any of these methods, it is imperative to carry out cleaning and degreasing procedures. This is a rather long and laborious process, so it is often neglected. But just from high-quality cleaning depends on the durability of the coating.

Cleaning can be mechanical and chemical, perfect option is a combination of these two methods. Mechanical cleaning is done with steel brushes or grinding discs. After that, the product is washed with aqueous detergent solutions. Greater efficiency gives subsequent sandblasting. It is especially necessary if you need to create a perfectly smooth painted surface or with increased requirements for the adhesion of the paint layer. Degreasing (chemical metalworking) is carried out mainly with alkaline, acidic or neutral solvents. After that, anti-corrosion treatment is carried out: conversion protection or phosphating the surface with a layer of inorganic paint is applied. If necessary, apply a primer layer.

If it is necessary to change the geometric shape of the products, then this is done before painting.

Types of coloring of metal products

All methods of painting metal can be divided into two groups:

• liquid;
• powder.

At liquid method choose mainly the following types colors:

• Oil. Used for indoor parts.
• Alkyd. She paints galvanized products.
• Acrylic. The best option for structures used outdoors.
• Polymer. They give the product additional electrical insulating properties.

Currently gaining more and more popularity powder coating. The essence of this technological process comes down to the following. A polymer-based powder coating is applied to the surface of the part. In the course of sputtering, the powdered substance is electrically charged. external source or due to particle friction. Through the resulting electric field, the smallest particles of the coloring agent are transferred to the surface of the product with the opposite charge. Elements not settled at the same time are captured by the installation. They can be used for re-painting, which ensures the highest quality of painting and the most economical use of materials. Then the part is placed in the polymerization chamber, where the powder layer melts and becomes solid.

As you can see, in terms of technology, powder coating is more complicated than liquid. But powder coating has a number of significant advantages, which explain its wide distribution:

• durability of the polymer layer, providing corrosion resistance;
• economy. At this method lost 1-4% coloring material, with liquid - 40%;
• higher resistance to any impact;
• lower toxicity, environmental and fire safety;
• long-term preservation of the original appearance;
• the ability to imitate any material, antique styling, overflow effect and create other decorative coatings.

Modern furnaces have different dimensions and configurations, so they allow you to paint parts of almost any shape and size.

O polymer coatings, many have heard today, but not many know how the application process takes place, especially when you consider that these are not liquid paints familiar to everyone, but a powder that is sprayed onto metal under the influence of electricity. In this article we will talk about what powder coating of metal products is and how it happens in large industries and in small private workshops.

The composition of the polymer powder is a complex chemical formula, which does not make sense to dwell on in this article. Let's put it simply - it is a heat-resistant, electrically charged powder for painting metal, which does not require dissolution in active solvents.

Today, this dye is increasingly used to paint cars and their individual parts, which are most exposed to negative effects.

Interesting! Painting metal with powder paint is not a cheap pleasure, and after all the work has been done, the price of the product can rise several times.

Theoretically, powder coating of metal can also be done in a garage or mini-workshop, but one cannot do without buying specialized equipment.

As we said above, painting occurs under the influence of electricity, that is, the spray gun must not only blow the powder through the nozzle, which in itself is an impossible task for simple tools, but also charge the paint with a positive charge of energy. Moreover, the product to be painted, in turn, must be energized, but have a negative charge, commonly called "mass".

It is this technology that makes it not easy to color a metal product, but also to introduce a coloring pigment into the molecular structure. If we talk about the advantages of this method of staining, then it will take a very long time to list them.

Therefore, we will focus only on the most significant, which are directly related to the quality of the coating:

• High adhesion with any metal surfaces.
• Resistant even to significant temperature changes.
• Completely insensitive to moisture and corrosion.
• Elasticity and resistance to mechanical damage. The product coated with a powder polymer does not lose a layer of paint during deformation, which is bent in the form of damage.
• The texture of powder paint is able to cover small flaws in the surface of the product.
• Powder paint is not only decorative coating , but also complete additional protection products from all kinds of influences, both natural and mechanical.

Of course, this paint cannot be called an ideal coating without flaws, but they are all associated with technical side question, that is, applying and removing:

• If flaws were made during the staining process, they will subsequently be very difficult to remove.
• As a rule, powder polymers are applied in three layers, which naturally affects the cost and speed of application.
• As mentioned above, for applying powder paint you will need special equipment, to do without which, it will not work out. Therefore, if you need to paint one product, then doing it yourself is unprofitable.
• Despite the fact that powder paint practically does not spread during application, the instructions for working with it require some experience and hardness of the hand.
• Only powder coating of metal products is possible, since other materials do not pass current, and therefore there will be no result.

As can be seen, the ratio of positive and negative qualities powder paint is almost the same, but despite this, its popularity is growing from year to year.

Coloring process

Despite quite high cost, powder paints for metal, have one interesting feature, namely, minimal losses during staining. This is relevant both for large factory workshops equipped with everything necessary equipment, and for do-it-yourself work, when the paint is applied not in a special sealed chamber, but in a garage or other small room.

The secret is that despite the rather high pressure, which the compressor produces, the powder is blown out of the spray gun very slowly, and the coloring occurs at a close distance from the metal, which prevents the paint from escaping in different directions. If we talk about specialized workshops, then powder coating of metal structures is carried out in sealed chambers, with special ventilation and a filter system.

Filters in this case perform two functions:

• Do not allow small particles of dust and flying debris to penetrate inside the chamber.
• Capture paint particles that have not come into contact with the product and store them for future use.

Important! When painting in a self-made workshop, you need to take care of complete sterility and tightness, since dust particles flying in the air can not only spoil the appearance of the product, but also disrupt the adhesion of the dye to the metal.

And you can clearly understand the whole process of working with polymer powder dyes by watching the video in this article.

Polymerization

Another feature of powder dyes is that after application, they need polymerization, which takes place in another chamber under the influence of high temperatures.

Moreover, the temperature level directly depends on which layer of the dye is polymerized:

• soil layer- polymerization at 160 degrees for 15 minutes.
• paint layer- polymerization at 180-190 degrees, for 20 minutes.
• Surface, decorative lacquer- polymerization at 200 degrees for half an hour.

Heat treatment is necessary for powder dyes, as they melt and seize even more tightly with the metal. Another plus of the polymerization process is that during the melting period, the paint spreads throughout the product and penetrates into those places where the spray gun could not penetrate.

The chamber itself is a sealed compartment equipped with automation and thermocouples, of which there must be at least two. Since one measures the temperature at the bottom of the chamber, and the second at the top. Sensors and automation analyze both indicators and issue middle level warming up.

In addition, automation controls the temperature increase and keeps it at required level within the given time.

By the way, it is quite possible to build a polymerization chamber on your own (see We make a do-it-yourself powder coating oven), for this you need to have some knowledge in electrics in order to calculate and install heating elements. Also be able to deal with welding machine to build a frame.

Important! It is strongly not recommended to use one chamber for painting and polymerization, since the paint deposited on the walls will come into contact with the metal and create wall insulation, as a result of which the temperature on the sensors will differ significantly from that which is actually in the chamber.

The painted product is placed in the polymerization chamber after each layer is applied and the required time is maintained, after which the heaters are turned off and the chamber is allowed to cool to a temperature of about 100 degrees, after which the product is removed and the final cooling occurs already at room temperature. Then you can move on to the next layer of paint or decorative varnish.

Summing up

As you can see, the process of working with polymer powder paints is quite complicated and time-consuming, but given all positive characteristics such coverage can be compensated most costs, since the painted product not only takes on the original appearance, but also receives additional corrosion protection, which no other types of paints can boast of.

Now, in the height of summer, let's talk about metal paint. Indeed, in warm summer weather, it is most convenient to paint metal structures - both in the city and, of course, in the country.

Gas and heating pipes, radiators and railings on balconies - in modern apartment there are many structures made of metal. AT suburban construction metal is used even more actively, appearing in the form of fences, gates, window bars, benches, swings, arbors, etc. There is nothing particularly surprising here. What other relatively affordable material can boast of similar strength, ductility, resistance to high and low temperatures? However, it also has weaknesses: without care and periodic processing, metal products are susceptible to corrosion.

Corrosion, or simply rust, occurs as a result of oxidative processes on the surface of the metal. The impact of the environment - rain, water vapor in the air - leads to the fact that the structure of the metal begins to collapse, and if measures are not taken in time, the product will not only lose its appearance, but also become unusable. This is the reason for the appearance in the construction industry special formulations protecting metal constructions from the influence of unfavorable external factors.

How to protect metal from rust?

There are two main approaches. The first is the use of a system of anti-corrosion primers and enamels, among which the most common option is alkyd materials on solvents. For example, in the USSR there was a popular primer GF-021 and enamel PF-115. Today, these materials are produced, as a rule, in the budget segment, although "expensive" manufacturers also have similar products.

The second option is the use of "3 in 1" materials, that is, such compositions that combine the properties of a primer, corrosion protection and enamel.

Enamels "3 in 1" are positioned as a product that can be applied to rust. Of course, this does not mean that the surface to be painted does not require preparation at all. Loose rusty layer, crumbling old paint, oil stains and other contaminants must be removed. Sometimes for this it is enough to pass over the surface with a stiff metal brush and degrease it with a solvent, more difficult cases a drill with a special brush attachment, sandblasting method, etc. can be used.

The surface is painted with a brush, roller or spray gun in at least 2 layers.

Enamels for painting metal directly on rust are usually produced in ready-made colors, unified with the standard colors of the metal profile (according to the RAL catalog). A popular type of product is hammer enamel (or hammer effect enamel), which, after staining, forms a light textured pattern on the surface, masking roughness and minor defects.

The main advantage of 3 in 1 enamels is the ability to get desired result using just one product, which saves a lot of effort and time. And it should be understood that in this case, price and quality are directly proportional to each other: the cheaper the paint, the less its reliability and service life.

Good to know…

1. Examining metal surface intended for painting, it is worth finding out which paint was used earlier. The danger is paints based on natural drying oil (oil), although today they have been almost completely replaced by synthetic enamels. You will not be able to repaint bituminous paints, which can be distinguished by a black glossy, even oily, surface (if you encounter them, it means that someone really wanted to save money on the initial painting). Paint that is not compatible with the newly applied compositions must be removed.

2. When choosing a paint, you should pay attention to following parameters:
The speed of drying "from dust" should be no more than 2-3 hours. In other words, the painted surface should dry as quickly as possible to such a state that dust and litter floating in the air do not stick to it, because metal painting is often done outdoors.
The period after which the next coat can be applied is important for the same reason: if the work takes place outdoors, it is better to complete it as soon as possible. short time so as not to become a victim of our changeable weather. Do not forget that to obtain a high-quality result, the enamel must be applied in at least two layers.
Paint consumption.

3. A separate issue is the coloring of galvanized surfaces. The main recommendations are not to paint "fresh", shiny galvanized steel and to use only those materials that expressly indicate that they can be used on galvanized steel.

Painting of heating radiators

Modern bimetallic and aluminum radiators usually not painted as they are factory powder coated and regular paint will not adhere well to them. All other batteries in the house can be repainted.

Contrary to popular belief, special heat resistance of the paint is not required. Any dispersion paints temperatures of +90C are maintained, alkyd enamels+120C, batteries never reach this temperature, otherwise it would be unsafe. But there is another problem: ordinary paints turn yellow over time under the action of elevated temperature(especially for solvent-based materials). Therefore, for the right paints, special binders and pigments are used. What to choose, water-based paint or solvent-based enamel, everyone decides for himself. The former are more environmentally friendly, dry quickly and practically do not smell, the latter have somewhat better performance properties. If desired, you can tint the material to give it a shade.

Before painting, the battery must be turned off. It is undesirable to paint hot batteries, since too fast drying of the material will affect the quality of the coating. If there is no other way out, apply the paint as thinly as possible.

For painting batteries, it is better to take special brushes that are curved at the end, and for painting pipes it is convenient to use semi-circular brushes at the end. Both those and others are sold in specialized stores.

The article was prepared by an expert from the CAPAROL ACADEMY.