| These recommendations cover the technology of steel sheet anticorrosion
protection, used to manufacture the products exposed to weather conditions,
including metal tile, wall panel etc.
Systems based on zinc-rich compositions ZFES and ZINOL are recommended
as anticorrosion steel sheet coating.ZINOL is one-package material on
high-molecular thermal plastic polymer and ultra-fine zinc powder base,
ready for use. ZFES is a two-package material, the ingredients of which
are ethyl-silicate binder and zinc powder, mixed immediately before application.
Viability of the prepared composition is 8 hours at least.
Coating schemes
ZINOL and ZFES coatings contain at least 90% of zinc in a dry film, and
it gives them the properties similar to those of hot-galvanized coatings.
Appearance of coatings - mat, grey. They may change the colour shade when
exposed to aggressive atmosphere because of zinc corrosion products of
white colour firmly stuck with the coating.To improve decorative properties
and to broaden colour range of the products, zinc-rich coatings are recommended
to be applied as primers followed by finishing by other paint-&-varnish
materials including aluminium-rich compositions ALPOL and PAES manufactured
by FMP or pentalphtaline, vinyl and other atmosphere-resistant enamels.
Aluminium-rich coatings are of silver colour, other enamels are produced
in a wide colour range.To reduce the costs of the coating it is allowed
to apply zinc-rich coating only to the external surface of the sheet which
contacts with open atmosphere.Protection scheme options of the sheet external
surface are given in the table:
| Primers |
Finishing |
Total thickness of the coating |
| ZINOL, 1 layer, thickness 30-40 µm |
ALPOL, 2 layers |
60-70 µm |
| ZFES#2, 1 layer, thickness 30-40 µm |
PAES, 2 layers |
60-70 µm |
Expected service life of the coatings is about 5-10 years depending on
the coating material, provided that the surface is prepared by blast-cleaning
to grade Sa 2,5 to ISO 8501-1:1988 and if application requirements are
observed. To prolong service life of the coating system it is advisable
to increase zinc-rich primer thickness up to 80-100 µm (2-3 layers).
Protection scheme options of the sheet internal surface:
- 1-2 layers of ALPOL coating or PAES with the thickness 10-30 µm
- 1-2 layers of atmosphere-resistant varnish, primer or enamel with
the thickness 10-30 µm.
Application method
- Unrolling the coil and cutting unto sheet.
- Sheet surface preparation for painting:
2.1. Surface degreasing;
2.2. Light sand blasting to remove oxides and scale or blasting with
electro-corundum up to grade Sa2 - Sa2,5 to ISO 8501-1: 1988 making
the surface a little rough.
This method is the most preferable oneSurface preparation must provide
the following coating characteristics: Adhesion by the lattice notch
method - maximum 2 points, impact strength not less than 40 cm. of the
coating used. When applying atmosphere-resistant varnish it is sufficient
to perform surface degreasing.
- Application of zinc-rich primer coat to the surface of the sheet.
- ZINOL and ZFES are applied to preliminary prepared surface with traditional
paint-&-varnish methods: pneumatic and airless spraying, with a brush,
with a roller. The drying time until tack-free in natural conditions
(at the temperature 20°C ±2°C) is approximately
20-30 minutes.
- Stamping the sheet for extrusion.
- Application of coating on the primed external surface of the sheet.
Application of coatings at the ambient air temperature (20°C
±2°C) and relative humidity of (65°C ±5°C)
% is performed in 2 hours at the earliest (for PAES, ALPOL) and 24 hours
for other coatings.The drying time can be reduced with induced ventilation
and (or) elevated temperature.
- Application of the protective coating to the internal surface of
the sheet. Drying.
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