Galvanized sheet painting - paint and tools

The polymeric coating on the corrugated board protects it from corrosion. The painting of the profiled sheet has a different texture, color, imitates natural materials. The surface of the facade or roof made of colored professional metal looks aesthetically pleasing and beautiful. Previously, they used galvanizing without polymer paint, the surfaces served for 20 - 25 years. Modern polymers work without degradation for about 45-50 years.

The need to paint corrugated board

Painted and galvanized profiled sheet is produced in the same way, the differences appear at the finishing stage. A layer of paint does not replace galvanizing, but complements its properties. Galvanized sheets without a polymer layer are used in temporary structures, outbuildings.

Painting the corrugated board increases the useful characteristics:

• hides scratches, chips;
• protects from precipitation, destruction, ultraviolet radiation;
• increases resistance to mechanical stress;
• protects against cracking at temperature extremes.

Decorative coloring of the profiled sheet is used to give a realistic surface to the walls of buildings. The facades look like massive structures made of stone, timber, brickwork.

Production types of coatings

Polymer film on the plane of the corrugated board increases the cost of the material, but the costs are justified by the additional qualities of the roofing and facade coating.

For painting in industrial conditions, the following types of polymers are used:

• Acrylic. Synthetic fiber is combined with particles of acrylic polymers, the coating burns out and is short-lived, 25 microns thick.
• Polyester. Retains color longer, but is easily damaged during transportation, thickness 25 microns.
• Plastisol. Hard to damage and scratch, 200 microns thick. They make an embossing under a stone, wood fibers.
• Pural. Contains polyamide, acrylic, polyurethane, thickness 50 microns.
• PVDF (polydifluorionate). The most durable and expensive coating of all, durable.

You can paint the corrugated board in a matte color or with a gloss. Matte is rougher, reflects more UV rays, therefore more durable than shiny.

Possibility of painting galvanized corrugated board

Plain zinc sheets without a polymer layer can be painted independently at home. Before starting work, the surface is degreased with special compounds, treated with an anti-corrosion primer. Epoxy and latex primers are more commonly used.

Each next layer is applied after the previous coating has completely dried. If you follow the technology exactly, you get high-quality, durable protection of an attractive look. Attention is paid to security measures.

Diy compositions for painting galvanized corrugated board

Paint for a profiled sheet must withstand temperature changes, not lose elasticity over time.

Types of paints are used:

• Alkyd, polyester and epoxy polyester enamel. Over time, small cracks appear on the plane, which significantly reduce the protection against corrosion. Elasticity does not suffer, such sheets can be bent.
• Acrylic compounds.Water-based paint in which an acrylate dispersion is combined with additives. The product adheres well to the surface, it is evenly applied. Over time, acrylic coatings fade a little, the color becomes less intense.
• Latex paints. The coatings are elastic, do not deteriorate over time, do not lose their original shine and shade. The plastic layer is difficult to damage and does not crack. The coating tolerates frost and UV rays well.

State standards are set out in GOST 24.045 - 1994, here the requirements for profiled steel panels are regulated, questions about the quality of coatings are raised. In the appendix under the letter "B" are indicated the standard coverings of the corrugated board and the recommended list of other compounds used for protection.

Paint for corrugated board is presented on sale in a variety of about 200 colors and shades. Standards can be viewed when purchasing paint in the German RAL catalog, the Finnish RR color scale, the Swedish PRELA color grid.

Green, brown colors are used for fences, roofs, facades are trimmed with gray, beige, chocolate, deep blue, red, burgundy are used for roofs.

Tools for easy application

To paint over chips, scratches received during installation, use paint for dyed profiled sheet, which is sold in cans, you can use spray guns. This is how the ends are tinted after cutting the profile to size during installation.

For self-painting, tools are used:

• brushes;
• rollers;
• spray guns.

It is not very convenient to paint profiled flooring with a roller, it can be used on protruding parts, then paint over hard-to-reach places with a brush.

It is most convenient to use pneumatic spray guns that supply paint under air pressure. Such units can be rented to quickly and efficiently apply a protective layer.

Technique for staining profiled sheet

The surface is preliminarily freed from rust, moss is removed, degreased, primed. Strongly rusty spots are cleaned with emery, phosphated with special agents. Degrease with soap solutions or acetone-based solvents. The remains of alkaline preparations are thoroughly washed off the sheets, dried, then other layers are applied.

Airless painting technology

A pneumatic spray gun with a special tip is used. The method is an application in which the paint is sprayed with the dispersion of a jet of paint and varnish composition.

Features of the method:

• The design of the nozzle allows you to reduce the pressure of the jet, therefore, a rarefied area of ​​coloring fog is obtained above the surface of the corrugated board or metal tile, the pressure drops to atmospheric values.
• This method is more suitable for flat surfaces, and on the profiled flooring you will get unpainted places, and you will need to repeat the procedure.

The result is not a very high-quality coating on the corrugated board.

Pneumatic spray method

Most often used at home when painting profiled metal on roofs, facades and fences. Spray guns are used, while paint particles are supplied to the surface under pressure and adhere well to it.

In this method, factors play a role:

• torch configuration and features of its design;
• the ratio between the size of the working plane and the pressure of the jet;
• speed of movement of colorful particles, their molecular weight.

Paint with a spray gun from a distance of 30 - 50 cm to obtain an even layer without drips. The disadvantages include the inefficiency of spraying, the toxicity of a foggy cloud around the place of work.

The combined method of painting corrugated board

The technique consists in the fact that for the movement of the emulsion and the formation of the torch, an increased air pressure is used. A stream emerges from the tip, which is similar in intensity to the airless method.

Painting features:

• Due to the special configuration of the nozzle and the action of compressed air, the particles of the coloring composition are additionally atomized.
• It turns out the ideal shape of the escaping torch.

The method is well suited for painting profiled sheets, since the result is a layer with optimal parameters. The method requires the use of expensive equipment, and is rarely used in small volumes in the private sector.

Powder coating

It is used more in industrial conditions, since high temperatures are required to melt the base of the powder composition.

Work order:

1. the area of ​​the sheets is degreased, primed and dried;
2. powder composition is applied with special spray guns;
3. the panels are polymerized by heating, while the paint is evenly melted on the surface.

The most commonly used pigments are rubber. The thickness of the layer plays a role; with an increase in this indicator, you can not only make a drawing on the surface, but also add embossing to increase the reality of perception.

Electrostatic method

A special spray gun is used that can generate an electromagnetic field. The equipment achieves maximum efficiency and operates economically. For corrugated board, they are rarely used, only if the waves are of a small height. Refers to modern technologies that allow painting the surfaces of fences, facades, roofs without loss of materials. Particles of paint receive a certain electric charge, move along the lines of the magnetic field that occurs between the tip of the unit and the surface of the profiled sheet.