Painting System

Most painting systems consist of two or more coatings, each having a different function. Basically, a complete paint system is composed of three major components/layers:

  • Primer or sealer
  • Undercoat
  • Finishing coat

Primer is the first coat of a painting system on ferrous metals and wood. It is required to enhance adhesion, to prevent absorption of subsequent coats by the porous nature of the substrate, as well as to prevent corrosion on metals. Sealer, on the other hand, is the first layer of a painting system on a cementitious substrate such as concrete and plastered walls.

The undercoat is the intermediate coat between the primer/sealer and the finishing, aimed to impart opacity and to add film build to the total paint system. In addition, it also promotes intercoating adhesion.

The final coat of a paint system is called a finishing coat. Besides being the frontline in protecting the substrate from adverse environmental conditions, it also provides the decorative function for the paint system, providing colour or gloss to the substrate. A textured finish can also be selected for a unique appearance, adding the attractiveness of the finished work.

KCC provides full range of products for use in different application and paint systems.

Selection of a Paint System

A suitable paint system must be selected for different requirements or substrates. A wrongly selected paint system may cause defects and may reduce the lifespan of the paint system.

KCC provides a wide range of selection for application on different substrates:

Woodwork or Timber :

For application on woodwork, it is essential to ensure that the moisture content of the wood is lower than 15%. It is also required to smoothen out the woodwork by sanding with fine or medium glass paper, and to seal up all joints, cracks, nail holes, etc. with wood putty. The woodwork should be primed with a coat of aluminium wood primer (e.g. KCC Alkyd 151AL), followed by an undercoat (e.g. KCC Alkyd 131UC), and finally finished with two coats of finishing top coat (e.g. KCC Koramel H2O).

Steelwork :

When painting over metal surfaces, ensure that all rust and dirt are thoroughly removed by scrapping and chipping, followed by sanding and solvent cleaning. The surface should then be primed with a coat of metal primer (e.g. KCC Metal-Prime 213ZP) and finally finished with two coats of finishing top coat (e.g. KCC Hi-Gloss Enamel). However, when painting over galvanized or non-ferrous substrates, it is essential to apply a coat of etching or wash primer (e.g. KCC PolyEtch 100) before applying the undercoat and the finishing top coat.

Masonry :

New concrete or plastered wall should be allowed to cure for at least 4 weeks. The moisture content must be lower than 12% as measured by a protimeter. To obtain the maximum performance of the paint system on the masonry, it is important to make sure that the surface of the concrete or plastered wall is clean, free of loose particles, and dry. On new masonry work, it is important to apply a coat of alkali resistant wall sealer (e.g. KCC Wall Sealer 500). On exterior wall surfaces, it is recommended to apply two coats of weather resistant finishing coat (e.g. KCC Korever). For a textured surface, a spray texture coating (e.g. KCC TextCoat 404) can be selected. For internal wall surfaces, high quality internal wall paint (e.g. KCC Spotless All-in-1) is recommended.

For old surfaces or repainting jobs, it is essential to remove dirt and old paint film with high pressure water jet. If there are algae or fungi growth, it is recommended to apply KCC fungicidal solution after the high pressure water wash.