Corrosion occurs when metal interacts with moisture and oxygen. This process develops especially rapidly outdoors, in industrial premises with high humidity, near chemically active substances and with constant temperature fluctuations. Rust not only worsens the appearance of the structure, but also gradually reduces the thickness of the metal, weakens joints and shortens the service life of the equipment.
Paints and primers for metal are used for processing fences, pipes, tanks, frames, production equipment and other structures. Depending on the condition of the surface, conventional anticorrosive primers, finishing enamels, rust compounds, corrosion transducers or cold galvanizing materials can be used.
Primer and enamel perform different tasks
The primer layer improves the adhesion of the finish coating to the substrate and reduces the risk of corrosion under the paint. The enamel forms an external protective layer that takes on the effects of precipitation, sunlight, pollution and mechanical stress. In demanding conditions, a full-fledged system of compatible primer and enamel is more often used.
Primer-enamels of the "3 in 1" format can combine several functions: transformation of residual rust, priming and decorative coloring. However, such compositions do not always replace a multilayer system. The choice depends on the condition of the metal, the expected service life of the coating and the operating conditions of the facility.
How to choose a coating system
There is no universal composition for all objects. The material is selected taking into account the type of substrate, its actual condition, operating conditions and requirements for the finished coating. For example, the exterior metal structure and the equipment inside the dry shop need different protection schemes.
The selection takes into account:
- the type of metal or the brand of the concrete base;
- the presence of corrosion, cracks and old coatings;
- contact with water, oils or chemicals;
- Operating temperature conditions;
- estimated mechanical loads;
- requirements for color and appearance.
Compliance with technology is more important than the number of layers
The reliability of the coating depends not only on the chosen material, but also on compliance with the application regulations. It is necessary to maintain the recommended layer thickness, inter-layer drying intervals and polymerization conditions. Applying too thick can lead to prolonged drying and defects, while applying too thin may not provide the required protection.
Well-chosen paint and varnish materials and proper surface preparation help slow down corrosion, reduce concrete destruction and prolong service life.