Professionals can identify a good product just by using it. Their expert eyes can see immediately whether the surface appearance is developing uniformly and whether the coating will withstand mechanical stress.
Metal is a versatile, highly stressable material. This is why it is used in many different forms in construction. But although metal components have outstanding static properties: only lasting protection from corrosion guarantees maximum value preservation and optimal durability. Ferrous metal (F-metal) and non-ferrous metal (NF metal, e.g. zinc) require different coating build-ups. First of all, it is important to check what metal the surface is made of:
F-metals must have corrosion protection. Otherwise they would quickly oxidize and eventually lose stability. Reliable, lasting and high-quality corrosion protection therefore starts with careful pretreatment of the substrate. DIN EN ISO 12944 defines the criteria for creating a coating that is as impermeable as possible. It stipulates that the required minimum thickness depends on two factors: the corrosiveness category, i.e. the protection duration to be achieved, and the bonding agent of the prime coat. Multi-Primer 227 and MP Thick Film 229 have proven effective as a corrosion protection system for iron and steel components.
It is important to inspect the coatings carefully before application. Due to the relatively low solid content in water-based paints, substrate roughness is tendentially less well leveled than with solvent-based alkyd resin enamel paints. The choice of the abrasive also has a significant impact on the quality of the surface. To prevent normal sandpaper from clogging: Treat acrylate surfaces with a paper that contains dust-repelling materials in the size coat. With a nonwoven abrasivel, on the other hand, the gaps are sufficiently large and therefore do not clog as easily. Our professional tips for checking the substrate:
Be cautious when using a factory-made prime coat or a coil coating. Conventional substrate testing methods such as scratch tests and cross-hatch adhesion tests may initially provide good adhesion data. Flaking may nevertheless occur after coating. The new coating should therefore always be matched to the existing old coating. 2C-Epoxi-Varioprimer is particularly suitable as a prime coat for coil coatings, powder coatings, and two-component coatings. In individual cases, the suitability must be checked on-site with a test coat.
Window and door frames, but also facade and balcony paneling, are often made of hard PVC. This can be coated for design reasons: to improve the appearance of components that have been weathered, for example. Or to create a different color design. However, the coating system must be specifically suitable for use on plastics. Silicones or waxes used as mold separating agents during plastics manufacturing also make adding a subsequent coating even more difficult. Our recommendation for a particularly durable prime coat: 2C-Epoxi-Varioprimer.
Our professional tips for checking the substrate: