Aiming for corrosivity categories C3–C5?
Solutions for higher corrosivity categories
Many contributing factors
The quality, corrosion resistance and durability of a paint finish are influenced by a large number of individual factors/steps. The right material shapes (such as rounding), surface (such as sanding, blasting and/or chemical pre-treatment) and paint choices influence the achievable corrosivity category. However, it should be noted that quality is influenced by many other factors as well, such as the suitability and purity of the pre-treatment solution and the paint shop equipment, as well as adjustments, the skill of the painter, oven temperatures, etc. In other words, the choice of chemical and paint alone does not guarantee good paint adhesion and corrosion protection.
Corrosivity category C3-M (salt spray 240 t) covers 80% of the products painted in Finland in terms of the requirements set by the climate conditions.
The Finnish coastline is so low in salinity that the climate does not impose a general requirement greater than category C3-M for painting systems. In general, higher category C ratings are required in environments such as mining, transport and industry. Similarly, international companies, including the maritime industry, often require higher corrosivity categories.
Examples of Polarco Oy’s solutions for various corrosivity categories with typical painting systems
One-step Toran
– Polished steel + Toran + PE powder paint / C3-M
– Polished steel + Toran + EP+PE powder paint / C3-H
– Blasted steel + Toran + PU wet paint / C4-M
– Blasted steel + Toran + PE powder paint / C4-H
– Blasted steel + Toran + Zinc-based EP + PE powder paint / C5-H
– Aluminium + Toran + PE powder paint / C5-H
Pronortec
– Steel + pre-wash + Pronortec + PE paint / 600–1,000 h (C5-M)