Aluminum products are lightweight, strong and durable. But along with a lot of positive qualities, they have one negative property - they are difficult to paint. The presence of professional equipment and premises easily solves this problem. To process this metal, manufacturers use acid, aluminum paint and other special materials.
Painting aluminum at home is also possible. It is carried out in several ways. And strict implementation of all recommendations will allow you to create a surface that will last quite a long time.
Features of the material
An oxide film forms on the surface of aluminum, like any metal. On aluminum it has the following features:
- the surface is covered with a thicker layer than on other metals, regardless of the processing method and environmental conditions;
- the film prevents moisture from reaching the surface, so water-based paints do not adhere to aluminum;
- oil paint also peels off - slower from smooth parts, faster from shaped parts.
Surface particles of the material come into contact with oxygen from the atmosphere. As a result, aluminum oxide is formed, covering the product with a dense layer. The metal appears to be dusted with white dust and is slightly rough to the touch.
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The oxide film protects the metal from corrosion, but prevents paint from adhering. Therefore, it must be removed chemically or increased adhesion by sanding and priming.
Varieties of suitable paints for painting
There are four types of aluminum paints that meet the requirements to varying degrees. Coatings have their pros and cons, so when choosing, you should take into account the purpose of the part to be painted.
Aniline
The main area of application of aniline dyes is the textile industry. They are available in powder and liquid form.
Aniline is a toxic substance, but after drying the product is safe for health.
Epoxy
Resins form the strongest compounds.
Durable epoxy paints typically consist of two components—a base compound and a volatile hardener.
Acrylic
The paint base is a polymer that adheres firmly to the surface.
Aerosol paints are easy to use. The sprayer can be used to paint hard-to-reach corners and small elements. Acrylic paints are also more varied in color. White compositions can be colored.
Powder
Another advantage of powder coating is the absence of toxic emissions from the composition or solvent, more economical consumption. Most often, to fix the dye, parts are subjected to heat treatment in a special heat installation, so the technology cannot be reproduced at home.
Requirements for coloring compositions
Aluminum is used in the manufacture of façade and hanging structures, engine parts, and vehicle bodies. Products are destroyed by precipitation and ultraviolet radiation. Therefore, the requirements for paints for exterior use are the highest: resistance to mechanical damage, constant exposure to moisture and temperature changes.
Aluminum is also used in shipbuilding. The oxide film serves as a good anti-corrosion coating, but if its integrity is damaged, paint must perform the protective function. Therefore, the coating for aluminum boats must provide reliable protection against mold and algae. In technical rooms with a high concentration of steam, aluminum without an oxide film is quickly destroyed. The paint should prevent fumes from reaching the metal.
Self-painting with anodizing
Materials are prepared before painting aluminum using anodizing and aniline:
- baking soda and ash salt - for electrolyte solution;
- aluminum container;
- power point;
- sandpaper sheet;
- vinegar 9% and aniline;
- degreasing agent.
The electrolyte is being prepared. A solution of salt (9 parts) and baking soda (1 part) is mixed in a glass container.
Before painting aluminum, it is sanded with a sheet of sandpaper and degreased. An object is immersed in a liquid. You cannot touch it with your hands.
The electrolyte solution is poured into an aluminum container. The product to be painted is immersed in it. The power supply point is connected to it with the positive pole, and to the container - with the negative pole.
Everything is left in this state for 2 hours.
Next, aniline CM is used. Its components: liquid - 1 liter, vinegar, 9% - 1 ml, dye - 15 g. all components are mixed and heated to 75-80 degrees. Painting an aluminum profile immersed in the solution will take 15 minutes. The longer the item is in the solution, the richer the shade will be.
At-Home Painting Instructions
In addition to choosing durable paint, the method of painting aluminum is important. There are three main methods of painting a specific metal. The most durable result is obtained after anodizing - keeping the part in an electrolyte solution under voltage.
Anodizing technology
To increase aluminum adhesion you will need:
- salt or soda;
- distilled water;
- glass and aluminum basin;
- fine-grained emery;
- battery with a current of 2 Amperes and a voltage of 12 Volts;
- electrodes;
- acetone.
Surface preparation:
- prepare a concentrated solution of salt or soda in different dishes;
- leave the concentrate for 15 minutes and strain;
- mix part of the solution with nine parts of water in a glass container;
- sand the aluminum part with sandpaper;
- degrease with acetone;
- rinse in water;
- Do not touch the washed part with your hands so that stains do not remain;
- dip in each solution in turn for 30 minutes;
- connect the anode to the part, the cathode to the container, connect the electrodes to the battery;
- give voltage for 1.5-2 hours.
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To prepare the coloring composition you will need:
- 15 grams of aniline dye;
- 1 milliliter acetic acid;
- liter of water.
How to paint a part:
- mix dye and acid in water;
- heat to 80 degrees;
- lower the prepared aluminum part into the mixture;
- take it out after 15 minutes.
For intense coloring, the part is kept in the solution longer, and for light tinting - less.
The color of anodized aluminum can be changed by holding the product in chemical solutions. The following table shows how to prepare them and obtain a certain shade:
| Solution 1 | Solution 2 | Color | ||
| Name of salt | Dosage in grams per liter of water | Name of salt | Dosage in grams per liter of water | |
| Hexation-(II)potassium ferrate | 10-50 | Iron(III) chloride | 10-100 | Blue, light blue |
| Hexation-(II)potassium ferrate | 50-100 | Copper(II) sulfate | 10-100 | Brown |
| Potassium dichromate | 50-100 | Lead acetate | 100-200 | Yellow |
| Potassium chromate | 5-10 | Silver nitrate | 50-100 | Orange |
| Barium chloride | 10-50 | Sodium sulfate | 10-50 | White |
| Cobalt acetate | 50-100 | Potassium permanganate | 25-30 | Black |
The part is kept alternately in the first and second solutions for 30 minutes, and then washed with distilled water.
Powder coating
Dyes in powders harden at high temperatures. Therefore, for coloring you will need a baking oven. In this case, the part must be absolutely clean.
How to properly prepare the surface:
- clean old paint with solvent;
- sand with fine sandpaper;
- degrease with alcohol;
- rinse in water;
- treat with alkaline and acid solutions;
- wash off traces of alkalis with distilled water.
Painting is carried out in two ways:
- ionized gun;
- baking.
For the first method, the part is grounded. Using a gun, an electrical discharge is applied to the powder particles and they are attracted to the aluminum surface. Industrial heat chambers are used to bake the paint. Both powder painting methods require special skills and equipment.
Painting with special primers and enamel
The method involves applying the compositions to aluminum without electric treatment.
For coloring you will need:
- primer for aluminum, stainless steel or chrome;
- fine-grained sandpaper;
- zinc-aluminum paint for metal;
- acetone or white spirit.
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How to prepare the part:
- clean the surface with sandpaper;
- treat with acetone or white spirit;
- apply primer in one layer;
- After 5 minutes, apply a second layer.
For painting over primer, it is better to use spray paint. The dye should be sprayed from bottom to top from a distance of 30 centimeters. The second layer can be applied after 20 minutes. For strength, apply 3-4 layers.
The part will dry completely after 6 hours. Varnishing will help to further strengthen the coating. Car varnish is suitable for fixing.
How to paint aluminum?
Several types of solutions can be used to paint this metal.
A set of special compositions are produced for painting non-ferrous metals
Acrylic mixtures
They are made on the basis of acrylic, which plays the role of a polymer. The most effective option is in cans. Aerosols allow you to apply a more uniform layer, which is impossible to achieve with a brush or roller.
Such solutions have the ability to withstand various temperatures, mechanical influences and moisture. Their application is accompanied by preliminary priming.
Acrylic in aerosols is the most convenient and easy to use
Aniline dyes
Such products are used primarily for working with textiles, wool and leather. But also this composition, or rather its solution, is an excellent option for coating aluminum surfaces. The products are available in liquid and powder form. When diluting them, certain safety measures are observed, because the dye has a toxic effect. Once applied, the coating does not pose a health hazard.
With the right approach, aniline compositions for fabrics can be used to paint metals.
Epoxy composition
An alternative to acrylic paints are epoxy mixtures; they are made on the basis of resins. The composition allows you to obtain a reliable, resistant and durable coating. But it is difficult to work with such material without appropriate experience, since the process must occur quite quickly.
Two-component epoxy compounds are highly durable
Important! Aluminum paint is selected with special care; preference is given to trusted manufacturers. It is necessary to have the necessary certificates.
Powder paints
This promising type of coloring composition is a powder that is applied with a special sprayer after preparing the base. The coating is obtained by melting the applied mixture, which requires complex equipment.
Professional equipment is required to apply powder paints
What affects the effectiveness of dyeing?
All actions for preparing and painting aluminum structures will be effective if certified materials are used in the work. This is necessary both for self-dying and for specialized companies. Powder dyes from the international concern based in the Netherlands, Akzo Nobel, and a brand from France, Bichon, are in demand on the Russian market.
If you contact a company that organizes a full cyclical process, the painting of the aluminum profile will be done quickly and with the highest quality. Price for painting aluminum profiles according to the price list: from 189 rubles per 1 m2.
Many companies that sell paints and varnishes for metal offer them in an assortment of colors. Moskovskaya offers a wide selection of paints according to the RAL catalog. There is contact by phone or by mail
