Metal paints for outdoor use

Exterior metal paints provide long-lasting protection for metals with economical paint consumption, high adhesion and resistance to weathering. Constant exposure to the environment thins the top layer. This causes it to crack, peel off and the gradual development of under-film corrosion. It is possible to increase the thickness of the coating, but this is not always practical. In addition, applying more coatings increases the consumption of corrosion protection agent.

If special products for outdoor use are used, the coating will not need to be renewed for at least 10-15 years. These include zinc primers which offer double corrosion protection. They can be applied at sub-zero temperatures and must first be cleaned of ice on the metal.

They are used as standalone coatings or as part of a complete protection system. In this case, the finishing coat is an aluminium paint or coloured paints. They reinforce the corrosion barrier by giving the metal a shiny and coloured appearance.
 

Coating systems for exterior applications

A combination of zinc-based primer and paint provides maximum protection. The system "primer + top coat" is recommended for structures operated in difficult conditions or aggressive environments. These coatings have a longer shelf life because the properties of the primer and topcoat are added. Complete systems are also used in the restoration of products to give them an aesthetic appearance. The primer coat itself has a grey matt colour, while the topcoats give the surface a glossy, textured or different shade.

1. Primer. Zinc-rich paint Zincor or Zincor-Spray is recommended as a primer coat. The zinc content is maximum for compositions of this class (up to 96%). The primer provides electrochemical protection and creates an external barrier layer. After application of one coat (40 µm) maintains anticorrosive properties of zinc coating for up to 10 years. Compatible with aluminium paints and coloured paints.

2. Finish coats. Protective and decorative paints are used for top coats. They contain aluminium powder or polymers with corrosion inhibitors. The colours can form glossy, textured or coloured coatings. Their service life is up to 5 years.

• Zincor-Aluminium. Paint with aluminium, designed to give metal surfaces an aluminium colour and gloss. The decorative effect is similar to hot-dip galvanising. Suitable for painting industrial and construction structures, for restoration of vehicles and agricultural machinery.

When choosing a system for exterior metal treatment, you should pay attention to its specifications. These always indicate the optimum application temperature. Zinc primers have a wider range and range from -30°C to +60°C. Protective and decorative paints can be used at temperatures from -20°C to +30°C.
 

Paint application in sub-zero temperatures

Low temperatures can last for several months in most parts of Russia. Zinc-containing paints for metal allow for corrosion protection in any season of the year. These compounds do not lose their properties at temperatures as low as -30°C and do not make outdoor cold galvanising more difficult. However, the durability and quality of the coating also depend on the application technology. There are a few important nuances to consider when working with paints and primers.

• Zinc-rich primers can be applied to damp surfaces (no big drops of water). In winter, however, moisture will form ice that must be removed from the metal. When painting during precipitation, the structures must be protected against rain and snow.
   
• Corrosion protection products contain different solvents. Zinc paints are used with non-aqueous solvents. As the temperature drops, their viscosity increases, so a thicker mixture is formed.
   
• At sub-zero temperatures, the curing time of all coatings increases. This also applies to anti-corrosive cold galvanising paints. The lower the temperature, the longer the polymerisation and curing time will be.
   
• When choosing the packaging, the application conditions must be taken into account. For example, using a spray in high winds can make painting difficult. Paint in buckets is more suitable for the winter season, especially if the area to be treated is large.
   

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