How To Paint Over Fibreglass

What Paint To Use On Fiberglass?

Follow our 3-step guide below on how to paint over fibreglass. For interior and exterior projects, with Zinsser Bulls Eye 1-2-3, Perma-White, and AllCoat products.

Note: this post has been updated with new information for painting over fibreglass.

Zinsser – The Benefits

Fibreglass can be tough to paint over as it needs to be suitably prepared and primed. This is so topcoats to properly adhere and stick to the surface. Zinsser’s Bulls Eye 1-2-3 is ideal for priming fibreglass as it provides a perfect key for topcoats.

Zinsser listens to contactors and develops new products, or adds features to existing products. This helps to meet their changing needs, delivering world class products that meet “real world” challenges. Zinsser provides tried and tested solutions to painting problems, such as painting over fibreglass.

 

Step 1. Surface Preparation

Prepare surfaces by ensuring they are clean and dry. Make sure they are free from anything that can interfere with the application or adhesion of materials and Zinsser products to be applied. Remove loose and failing material by scraping or brushing with a stiff bristle brush to a sound edge.

Feather the sound edges with a fine grade abrasive paper, removing all visible signs of organic growth and using Zinsser Mould Killer & Remover to treat areas (in accordance with the manufacturer’s instructions) before allowing them to dry.

 

Step 2. Priming

Use methylated spirit to ensure the surface is free from any contaminants and anything that could interfere with adhesion, frequently changing the cloth, before priming overall with one full coat of Zinsser Bulls Eye 1-2-3.

Apply the primer in accordance with the manufacturer’s instructions and allow a minimum drying time of 1 hour (in normal drying conditions).

 

Step 3. Decoration

Decorate interior surfaces with two full coats of Zinsser Perma-White Interior, in accordance with the manufacturer’s instructions, and allow a minimum drying time of two hours between coats.

Zinsser Perma-White Interior is available in Matt, Satin and Semi-Gloss finishes with over 4,000+ colours from RAL, NCS, and British Standard.

For exterior projects, decorate with two full coats of Zinsser AllCoat Exterior in accordance with the manufacturer’s instructions. Allow a minimum drying time of one hour between coats.

Available in water-based and solvent-based products, Zinsser AllCoat Exterior has Matt, Satin and Gloss finishes in a selection of over 4,000+ colours from RAL, NCS, and British Standard.

 

How to Paint Over Fiberglass: Mastering a Craft

Painting over fiberglass isn’t just about slapping on a coat of paint and hoping for the best. It’s a delicate process that requires a clear understanding of the material and its properties. Fiberglass is known for its durability and wide-ranging applications. However these same characteristics can make it difficult to work with when it comes to painting. Whatever you’re looking to update the appearance of – a boat hull, a shower stall, or any other fiberglass surface – the success of your project hinges on careful preparation and the right technique.

Understanding the Nature of Fiberglass

Fiberglass is a composite material made of fine glass fibres embedded in a resin matrix. It is often used because of its strength, lightweight properties, and resistance to water and chemicals. These qualities make it an excellent choice for various applications:  automotive bodies, marine vessels, and home fixtures like bathtubs and showers. However, the same qualities that make fiberglass so useful also presents challenges when it comes to painting.

Fiberglass surfaces are typically slick and non-porous. Unlike wood, which has a grain that can absorb paint, or metal, which can be treated to hold paint better, fiberglass doesn’t easily allow paint to adhere to its surface. The slickness of fiberglass means that paint applied directly to it is likely to peel or chip away over time. Especially important when the surface is subjected to stress, temperature changes, or moisture.

To effectively paint over fiberglass, it’s crucial to alter the surface texture so that it can hold onto the paint. This requires a series of preparatory steps that include cleaning, sanding, and priming, to ensure that the paint adheres well.

 

The First Surprise: Fiberglass Isn’t Indestructible

While fiberglass is often associated with toughness and resilience, these qualities can sometimes be misleading. It’s easy to assume that because fiberglass is so strong that it doesn’t need much in the way of preparation or protection. However, this very resilience is what makes painting over fiberglass so challenging.

Fiberglass’s strength comes from its composite nature, but this also means that it’s not a material that can easily be penetrated by paint. This is why a fiberglass surface needs to be roughened slightly through sanding before any paint can be applied.

The durability of fiberglass means that if the paint doesn’t adhere properly, it can peel or crack. This exposes the underlying fiberglass. Over time, this exposure can lead to further degradation. This is especially propblematic in environments where the fiberglass is exposed to moisture or UV rays. In marine environments, poorly adhered paint can lead to blistering, peeling, and even damage to the fiberglass itself due to prolonged exposure to water.

 

Why Preparation is Non-Negotiable

To paint over fiberglass successfully, preparation is absolutely key. It involves more than just a quick wipe-down and a coat of paint. Proper preparation includes a thorough cleaning to remove any dirt, grease, or wax. These could prevent adhesion, so sand to create a surface that the paint can cling to, and apply a primer specifically designed for fiberglass. Each of these steps plays a critical role in ensuring that the paint adheres properly and provides a long-lasting finish.

Skipping any of these steps can lead to the paint failing. If the surface isn’t sanded, the paint might look fine initially but could start peeling or chipping after a few months, especially if the object is exposed to the elements or frequent use. Similarly, without a primer, the paint might not bond well to the fiberglass, leading to poor coverage and durability.

Take the time to prepare fiberglass surfaces properly, ensuring that paint jobs look good when finished and stand up to the rigors of use and exposure. Whether painting a boat that will be exposed to saltwater; a shower stall that will see daily use; a decorative piece that needs to last for years. Proper preparation of fibreglass is the foundation of a successful paint project.

 

The Importance of Patience and Attention to Detail

When painting over fiberglass, patience and attention to detail are your best allies. Each step in the preparation process should be done carefully and thoroughly. Don’t rush through the sanding, and make sure every part of the surface is treated. Take the time to clean off all sanding dust and make sure the primer is applied evenly. When it comes to painting, multiple thin coats are better than one thick coat, these reduce risk of drips and ensure even coverage.

The time and effort you invest in preparing the fiberglass surface will pay off in the end. Not only will you achieve a smooth, even finish, but you’ll also extend the life of the paint job, ensuring that your work looks great and holds up over time. By mastering the craft of painting over fiberglass, you’ll be able to take on a wide range of projects with confidence, knowing that you have the skills and knowledge to achieve professional results.

 

More Information

If you require more advice on painting over fibreglass, leave a comment below for our technical team to review or give our technical team a call on 0113 2455450 (option 2) – or send a message to [email protected].

Posted: 23rd October 2019 | Updated: 10th September 2024