Priming of metal surfaces

Priming is the operation by which the first film of material is applied to the metal surface, which is the basis for subsequent coatings.

The primer film has the role of making a good connection between the metal surface and the next film that overlaps the primer. This primer film can perform several functions: insulating the metal from the environment (through the binder), coloring (through the pigment) and anti-corrosion protection.

The priming process can be applied both on metal surfaces made of cast iron, steel or stainless steel alloys. As well as on non-ferrous metal surfaces (alloys of Cu, Al, Zn, etc.)

The following question often arises: „Why is it necessary to prime metal surfaces, is painting not enough?”

The answer to this question is given by the advantages that the primer presents:

– protects the metal from rust;

– helps the decorative layers (enamel or glossy paint) to stick better;

– avoid exfoliation and cracking of the enamel/paint film;

– gives the paint film a uniform, smooth appearance.

Priming of the metal surface – Methods of applying the primer layer:

– with the brush;

– by spraying;

– by immersion.

Each method can give good results if it is applied correctly. Immersion is the most efficient and economical method, obtaining a superior surface quality.

The primer layer can be used both for the protection of new metal surfaces and for the maintenance of previously painted surfaces, as follows:

– if the metal surface is new: remove the metal oxides, degrease the surface, then apply a layer or two of primer, respecting the drying times recommended by the manufacturer

– for metallic surfaces that have been painted before: remove the old paint that no longer has adhesion: mechanically or chemically, then follow the same steps as above

The primer is chosen according to the metal to be covered and according to the nature of the paint. Also of the varnish that is applied over the primer layer.

Types of primers:

– zinc-rich epoxy primer suitable for galvanized surfaces;

– primer that lends itself to rusty surfaces and is also weldable;

– quick-drying red, gray and black primers – is an anti-corrosive primer based on synthetic resin.

It is ideal for anti-corrosion protection of metal surfaces, metal parts, structures.

Most of the time, primers protect the metal surface against corrosion, but they also help to level the surface and improve the final paint.

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How do we protect the galvanized sheet

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