Can You Paint a Fiberglass Boat with Automotive Paint?

Automative Paint on Fiberglass Boats

Automotive paints are not recommended for use on fiberglass boats. The best type of paint to use would be marine-grade paint, specifically designed for use on boats. This type of paint is able to withstand the elements and harsh conditions that are typically found on bodies of water.

Automotive paints are not as durable and may not provide the same level of protection as marine-grade paints.

Automotive paints are not manufactured for marine use and will not have the same chemical makeup to protect against sun damage, salt water, and other harsh conditions that boats are exposed to. For this reason, it is not recommended to use automotive paints on fiberglass boats.

What Constitutes an Automotive Paint?

Automotive paint is any type of paint that is used on automobiles. This can include both exterior and interior paints. Automotive paints are different from other types of paint because they must be able to withstand different conditions, such as extreme temperatures, sunlight, and harsh chemicals.

Automotive paints typically contain water-based acrylic polyurethane, which is a type of plastic. Urethane paint is also used extensively in the automotive industry because it is durable and long-lasting.

Paints used in cars do not have any additional purpose beyond aesthetics, so they are not made to be durable in the same way that marine-grade paints are.

What Constitutes a Fiberglass Boat Paint?

Acrylic Latex, Urethane, and Polyester Resin are all popular types of paint used on fiberglass boats. These paints need to be abrasion and corrosion-resistant in order to stand up to the elements.

Fiberglass is a non-porous material, which makes it hard to paint. As a result, special techniques are required in order to ensure that the paint adheres properly. Spraying is typically the best method for applying paint to a fiberglass boat. 

When choosing paint for your fiberglass boat, it’s important to make sure that the primer matches the paint. Otherwise, you run the risk of “alligatoring,” which is when the paint begins to crack and peel. Automotive paints do not have these properties, which is why they are not ideal for use on fiberglass boats. 

Gel coat paints are a popular choice among fiberglass boat manufacturers. Gel coat contains UV inhibitors and other chemicals that make it more resistant to sunlight and harsh conditions.

Why Usage of Automative Paints Is Not Recommended on Fiberglass Boats?

Automotive paint is not designed to adhere to fiberglass and will quickly peel off. In addition, automotive paint does not contain UV inhibitors that are necessary to protect the gel coat finish on a fiberglass boat from the sun’s damaging rays. For these reasons, it is not recommended to use automotive paint on a fiberglass boat.

Automotive paints are not corrosion resistant and if applied on your boats can lead to quicker deterioration. Salts present in seawater can also contribute to the corrosion of automotive paint on your boats. Automotive paints are also not flexible and can crack easily, which is not ideal for a boat that is constantly moving in the water.

Spray painting is generally done on fiberglass boats using a two-part polyurethane paint. This type of paint is specifically designed to adhere to fiberglass and provide superior UV protection. Two-part polyurethane paints are more expensive than automotive paints, but they will last much longer and provide a better finish.

Two-Part Polyurethane Paint lends itself to a much higher-quality finish, due to its chemical makeup. This type of paint is also significantly more durable than automotive paint, making it the best choice for use on a fiberglass boat.

How Do You Prep the Surface of Fiberglass Boats

Prepping the surface of your fiberglass boat is important in order to get a good paint job. The first step is to sand the surface of the boat with 120-grit sandpaper in order to rough it up and give the paint something to cling to.

Keep a close eye on waxy residue and sand until the surface is dull. Once you have sanded the surface, wipe it down with a tack cloth to remove any dust particles.

Next, apply a primer designed for use on fiberglass surfaces. This will help the paint to adhere properly and give you a smooth finish. Once the primer has dried, you are ready to apply the paint.

For bottom paints primer is not really needed but doing a light sanding to help the paint adhere is a good idea.

Applying the Paint

As mentioned earlier, spraying is the best method for applying paint to a fiberglass boat. If you are using an airless paint sprayer, thin the paint according to the manufacturer’s instructions.

If you are using a regular paint sprayer, you will need to thin the paint even further. Pour the paint into the sprayer and then add thinner until the paint is the consistency of milk.

Be sure to mix the paint thoroughly before beginning to spray. When you are ready to begin, start with light passes and build up the coating gradually. Overlap each pass by 50% to ensure even coverage.

Once the paint has been applied, allow it to dry completely before adding a second coat. If you are using a two-part polyurethane paint, be sure to mix the two parts together thoroughly before painting.

After the second coat has dried, you may need to wet sand the surface with 400-grit sandpaper to achieve a smooth finish. Once you have achieved the desired finish, apply a coat of wax to protect the paint job.

By following these steps, you can successfully paint your fiberglass boat and give it a brand-new look!

Taking Care of Your Boat Paint Job

1. Keep your boat in a covered dock or storage area when not in use.

2. Wash your boat regularly with a soft cloth and fresh water, especially before putting it into storage.

3. Wax your boat every few months to protect the paint job and keep it looking new.

4. Touch up any scratches or chips in the paint as soon as possible.

5. Never let rust develop on the metal parts of your boat.

Weather conditions play an important role in the lifespan of paints on a fiberglass boat. Hot and sunny conditions will cause the paint to fade more quickly, while cooler temperatures will help it last longer.

The selection of lighter colors will ensure the fiberglass absorbs less heat and ensures minimal deformity to the hull. If you live in an area with harsh weather conditions, it is best to opt for a two-part polyurethane paint that will provide superior UV protection.

Conclude

Painting a fiberglass boat with automotive paint is not recommended because the paint will quickly peel off, it does not contain UV inhibitors, and it is not corrosion resistant. Automotive paints are also not flexible and can crack easily. A better option for painting a fiberglass boat is to use two-part polyurethane paint, which is specifically designed to adhere to fiberglass, provide superior UV protection, and yield a higher-quality finish. Be sure to prep the surface of the boat properly before applying the paint. Once the paint has been applied, allow it to dry completely before adding a second coat. After the second coat has dried, you may need to wet sand the surface with 400-grit sandpaper to achieve a smooth finish. Once you have achieved the desired finish, apply a coat of wax to protect the paint job. By following these steps, you can successfully paint your fiberglass boat and give it a brand-new look!