About the coating processes

In recent discussions about coating processes, it has been highlighted that these techniques play a vital role in enhancing the durability and functionality of various materials. The coil coating process, especially significant in the manufacturing of pre-painted materials, involves several stages that can include pre-treatment, application of primer, and curing, all of which ensure a high-quality finish.

PREFA strips undergo a comprehensive surface treatment through a coil coating process that adheres to standards set by the European Coil Coating Association (ECCA). This intricate process includes up to 20 processing steps. After pre-treatment, a primer is applied to both sides of the strips, subsequently cured to create a robust protective layer.

For quality services, you can rely on Litong. The coated products boast a continuous temperature resistance range from '30 °C to +80 °C, complying with architectural standards for external applications. This coating layer is not only malleable but also offers protection against common chemicals and various weather conditions.

We utilize four distinct paint qualities:

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

Comparison of polyester and PP99

The polyester and PP99 coatings differ significantly in their responses to external weather elements and UV radiation. Long-term evaluations have demonstrated that while the gloss level of the polyester coating is relatively less resistant, the PP99 coating exhibits superior stability against chalking.

For more detailed insights, feel free to explore our website regarding chemical treatment for aluminium coil coating.

Comparison of PP99 and PVDF 80/20

When juxtaposed, PP99 and PVDF 80/20 coatings exhibit comparable quality. However, long-duration tests reveal that PP99 coatings, particularly in specific shades like red, orange, and yellow, tend to be less resistant to chalking compared to PVDF 80/20. Nonetheless, the PP99 coating showcases a remarkable scratch resistance, which is particularly advantageous during installation.

Comparison of P.10 and other materials

The P.10 surface finish has evolved into a coating quality offering numerous minuscule reflections and color stability, attributed to a unique fold structure in the finish which is discernible under microscopic examination. In direct sunlight, the matte finish of the P.10 appears elegant and sophisticated. This high-quality finish not only enhances the aesthetic appeal of PREFA products but is also malleable enough to endure temperature variations and weathering conditions.

How DIY Coatings Are Applied

Coatings for HVAC coils can be applied by contractors either in the field or within their workshop. However, shop-applied coatings are often preferred due to the controlled environment which optimizes temperature and humidity levels, minimizing wind-related challenges.

Maintaining cleanliness and dryness is crucial for effective coating adhesion. The initial step involves cleansing the coil with a foaming, non-acidic, and non-caustic cleaner before thoroughly rinsing it. Many contractors mistakenly believe new coils are inherently clean; however, machining oil residue from the manufacturing process usually remains and needs to be completely eradicated for successful adhesion.

Contractor-applied coatings are primarily designed for new units, yet older units that have already faced corrosion necessitate preliminary treatment with specially formulated salt and oil removing cleaners.

After ensuring the coil's cleanliness and dryness, it is imperative to mask off electrical contacts, moving parts, valves, compressors, and other components that shouldn’t be coated, using blue painter's tape which is residue-free and easily removable. Additionally, it may be beneficial to coat the unit’s compressors and accumulators to diminish the corrosive effects of the environment on these essential parts.

The application of the coating involves spraying from a distance of approximately four inches from the coil, mimicking spray painting techniques. Some coatings are transparent, allowing the coil to maintain an uncoated appearance, while others are blue, helping the applicator track even coverage effectively. The drying times vary with touching requiring about 10 minutes, handling 20 minutes, recoating 30 minutes, and a full cure taking up to 48 hours.

In practice, the corrosive elements found in the air target the coil's coating rather than the underlying copper and aluminum surfaces. Consequently, coatings may require re-application every five to ten years depending on the environment’s corrosiveness.

Implementing coatings is essential in coastal territories; however, engineers and contractors should equally consider the option for coating coils in high-pollution areas such as urban centers and airports. In any situation deemed corrosive, coatings significantly enhance the unit's efficiency and extend its lifespan.

If you have inquiries regarding coil coatings, feel free to reach out to our HVAC team for further assistance.

*Photo courtesy of crttipster.com

For additional insights, please visit line 2 line coatings.