About the coating processes

PREFA strips undergo surface treatment in a coil coating process in accordance with the ECCA (European Coil Coating Association). In the process, the strips go through up to 20 processing steps. After pre-treatment, primer is applied to both sides, and cured. 

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With a continuous temperature resistance of &#;30 °C to +80 °C, the product complies with the requirements of outside architecture. The coating layer is malleable and protected against general chemicals and weather conditions.

We use four different paint qualities:

• polyester
• PP99 (polyamide / polyurethane)
• PVDF 80/20 (polyvinylidene fluoride)
• P.10

Comparison of polyester and PP99

The difference between polyester and PP99 coatings lies in their different reactions to external weather conditions and UV rays. Long-term tests have shown that the gloss level of the polyester coating is less resistant than the PP99 coating. The polyester coating is also less resistant to chalking than the PP99 coating.

If you want to learn more, please visit our website chemical treatment for aluminium coil coating.

Comparison of PP99 and PVDF 80/20

The quality of the PP99 coating is broadly similar to that of the PVDF 80/20 coating. Long-term tests have shown that the PP99 coating in special shades (such as red, orange and yellow) is not as resistant to chalking as the PVDF 80/20 coating. However, the PP99 coating has high scratch resistance (an advantage during installation).

Comparison of P.10 and other materials

Since , the P.10 surface finish has produced a coating quality that provides countless minuscule reflections and colour stability through a special fold structure in the finish that only becomes visible under a microscope. In direct sunlight, the matte surface of the P.10 finish has an elegant appearance. The high-quality surface finish on PREFA products is malleable and is able to withstand temperature fluctuations and weathering.

How DIY Coatings Are Applied

Contractors can apply DIY coil coatings in the field, or in their shop. Obviously, shop-applied coatings are preferred, because of the controlled environment for temperature, humidity with no challenges from wind.

&#;Clean&#; and &#;dry&#; are key to a good coating adhesion. The first step mandates cleaning the coil with a foaming, non-acid, non-caustic coil cleaner and then thoroughly rinsing the coil. Many contractors believe that new coils are clean. However, most new coils have machining oil residue from the manufacturing process that must be fully removed for successful coating adhesion.

While contractor-applied coatings are designed for new units, if an older unit that has already been exposed to corrosion is being coated, it should be treated first with a purposely-formulated salt and oil removing coil cleaner.

Once the coil has been cleaned and is completely dry, the electrical contacts, moving parts, valves, compressors and other parts not to be coated, are masked off with blue painter&#;s tape, which doesn&#;t leave a residue and is easily removed. It might also be beneficial to coat the unit&#;s compressors and accumulator to minimize the corrosive environment&#;s effect on these key components.

The coating stream is sprayed approximately 4-inches away from the coil in similar movements to spray painting. Some coatings are clear, which allow the coil to appear aesthetically uncoated. Other coatings are blue, for when the applicator prefers to visibly track even coverage of the sprayed area. Drying times for touching is 10 minutes; handling is 20 minutes; recoating is 30 minutes; and a full cure typically requires 48 hours.

During use, the corrosive elements in the air will attack the coil&#;s coating instead of the copper and aluminum surfaces. For this reason, coatings may need a re-application every five to 10 years depending on the environment&#;s corrosiveness.

Coatings are essential for coastal areas, however engineers and contractors should also consider the prospect of coating coils in high air pollution areas such as urban centers and airports also. In any corrosive situation, coatings will help improve the efficiency of the unit and maximize the unit&#;s useful life.&#;

Have a question about coil coatings? Contact our HVAC business for more information.

*Photo courtesy of crttipster.com

For more information, please visit line 2 line coatings.