Understanding and Tackling Microblistering in Marine Coatings

Understanding and Tackling Microblistering in Marine Coatings

Marine coatings are essential for protecting ships and other marine structures from the harsh marine conditions, including UV, salt water, corrosion, fouling, and abrasion. However, problems can arise with marine coatings over time or after application.

Microblistering is an issues that can be encountered with marine coatings and this article is designed to provide suggestions on how to prevent and address it effectively.

Microblistering

Microblistering: Is mainly caused by moisture trapped between layers of paint. The conditions that enable this to occur include high-humidity, dampness, unsuitable temperature and contamination during the application and curing process.

This causes diffusion of moisture through the paint film. The moisture accumulates between the layers of paint with the least adhesion, or where there is contamination and forms blisters.

How To Avoid

Make sure to apply the coating in the correct conditions, ideally in the spring and summer months of the year.

Make sure to avoid evenings through to early mornings, where humidity is likely to be at it's highest.

Minimum application temperature is 5 degrees centigrade and relative humidity should be < 80%, air temperature between 10 – 30 degrees, substrate should be a minimum of 7 degrees and at least 3 degrees above the dew point.

After sanding between coats remove any dust and contamination.

Make sure there is no salt or moisture on the surface before painting. 

Solution 

1. Clean the affected area thoroughly to remove any contaminants.

2. Carefully remove the paint in the area where the blistered are, take the surface back to sound. Use a scraper or sandpaper to expose the blisters without causing additional damage.

3. Allow the exposed area to dry completely. This step is crucial to ensure that moisture is eliminated from the damaged layers.

4. sand the area to achieve a smooth and even surface.

5. Apply a coat of Marine Primer Undercoat (if required). 

6. Apply one or two coats of Marine Gloss. 

*Be mindful of temperature and humidity conditions during the application and curing of the paint. Ensure that the paint has adequate time to cure properly.

 

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