Metal painting is a complex, time-consuming and painstaking process, as it is one of the most difficult matterials to paint. Quality painted metal will be protected from external influences and will not lose its commercial appearance. There are several ways of painting metal. One of the most widely used for protection of metals from corrosion is anti-corrosive paint.
Is it necessary to paint metals?
Corrosion is the decomposition of a metal due to chemical or physical interactions with the environment. Metal oxidizes and loses its characteristic properties. Rust spreads more and more over time and damages metal. Meanwhile, the painted surface is covered with a thin, oxygen-proof layer that prevents further corrosion processes. Unprotected metals can cause significant losses.
Operating environment of metal structures
Before painting, it is important to evaluate the degree of aggressiveness of the environment in which the metal will be stored. It is evaluated according to the international standard – EN ISO 12944-2. There are 6 main categories of atmospheric corrosion:
- C1 – very low;
- C2 – low;
- C3 – average;
- C4 – high;
- C5-1 – very high – industrial;
- C5-2 – very high – marine.
These categories are based in the reduction of thickness of metal samples, made of steel and zinc, kept in these conditions for a year.
Anti-corrosion painting of metals
One of the main ways to protect metals is to paint them. Anti-corrosion painting helps to prevent the undesired corrosion process, reduces the negative effects of various chemical elements and increases the resistance to abrasion. Finally, it gives the metals a better look.
There are 3 stages of anti-corrosion painting:
– Sandblasting of metal surfaces: This is one of the most effective surface preparation techniques. During sanding, the surfaces of the parts roughen and micro recesses are created, which ensures high-quality adhesion of the coatings. Sandblasting saves time when working even in hard-to-reach places. Metal, slag, quartz sand and a number of other abrasives are used for cleaning, they make the surface rough and remove old paints and varnishes.
– Priming: On a thoroughly cleaned surface, a primer is applied that dries and forms a surface to which the paint adheres perfectly. A second layer of primer is applied after the first layer. This double priming helps to protect metals from oxidation, high humidity, corrosion and ensures longevity.
– Painting: After careful scraping and priming, the surface can be painted. Metal painting can be done by choosing various paints adapted for this purpose. The most important thing is that they are of high quality and help to achieve the desired result. If the shelf life of the coating is shorted than the intended service life of the metal structure, the reniewal of the coating must be ensured.
Metal painting saves a lot of money and time for effective corrosion protection. Not sure which painting method to choose? Our team will provide detailed advice on the issues you care about.