Blog – Paintings and Coatings

5 Important Reasons Surface Coatings Fail

A surface coating is only as good as the surface coating preparation and the environmental conditions throughout the process. Without the ideal coating materials and ambient conditions, the coating material might fall victim to corrosion or fail to adhere to a substrate correctly. Since premature failures are generally the result of preventable circumstances, knowing what to monitor and consider will help ensure a successful coating application, prevent timeline delays and avoid budgetary problems.

Why a Surface Coating Fails

Improper surface coating preparation: Even when using a coating that’s suitable for the intended environment, a substrate’s cleanliness affects the coating’s performance. The goal of surface coating preparation is to free the substrate of contaminants, such as:

- Weld splatter and fumes
- Oxidation
- Oil
- Dirt, dust, and other particulates
- Salts
- Welding burn-through
- Ionic species
- Moisture

The best method for cleaning a substrate depends on its composition, age, the contaminants found on its surface, and the type of coating that already exists on its surface.

Lack of monitoring: Successful coatings require constant monitoring and control of the ambient conditions from the moment that the surface preparation tasks begin to at least 48 hours after applying the final coat. If conditions do not remain ideal between the cleaning and coating process or between each coating, the surface is at high risk for contamination and oxidation.

Uncontrolled temperatures and relative humidity levels: In general, the best temperatures in which to apply a surface coating are between 56°F and 99°F, depending on the coating type and manufacturer’s instructions. Temperatures that are too hot cause coatings to dry too quickly, while lower air temperatures delay drying and curing times.

Inadequate surface temperatures: During the day, a surface may absorb heat, making it hotter than the air’s temperature—similar to a metal slide on a summer day. At night, the surface will radiate the heat that it absorbed. The temperature changes affect the coating’s adhesion and promote the formation of condensation. Resulting problems include catering, pin holing, blistering, and oxidation. Depending on the dew point, surface temperatures should match the manufacturer’s specifications and air temperatures, which should remain constant throughout the process.

Poor ventilation: A lack of ventilation leads to the accumulation and entrapment of solvents, which negatively affect coating applications. It may also promote oxidation and mold growth. It is best to use a forced ventilation system during the surface preparation and coating processes, and for at least 48 hours after the final coating application.

The weather is unreliable and HVAC systems cannot effectively provide adequate conditions for surface coating projects. The best proactive approach to meet deadlines, stay within budget and ensure the success of a surface coating is with Polygon’s temporary humidity control solutions. Specialists custom design the equipment for your exact needs to give you the ultimate control over ambient conditions and keep your crew productive. Get in touch with Polygon today to learn more and schedule a complimentary consultation. 

[Photo from Håkan Dahlström via CC License 2.0]

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