Protecting Your Boat: Best Sealants For Wooden Surfaces

Wooden boats need to be sealed to protect them from the elements and keep them looking new. The sealing process should take into account the type of wood the boat is made out of, as some woods are more resistant to rot than others. One of the most important functions of a sealer is to protect the boat from UV damage, which can cause the wood to fade and crack over time. A good sealer will also protect the boat from water damage, as water can cause the wood to swell and rot. The sealing process typically involves cleaning and sanding the wood, applying a sealer, and then applying a topcoat for additional protection. While there are various methods and products available for sealing a wooden boat, it is important to use a professional marine-grade sealer to ensure the strongest barrier and the longest-lasting protection.

Sanding and painting

Before you begin, ensure you have all the materials required for waterproofing your wooden boat and place them in an organised manner in your work area. Cover the floor with a tarpaulin to avoid making a mess.

The first step is to clean the wood thoroughly. Use a clean rag or paper towel with acetone to remove any contaminants like oil, grease, wax, and mould. It is important to do this before sanding to prevent further contamination. Remember to wear a mask and safety gloves and work in a well-ventilated area when handling acetone.

Next, use a fan, hairdryer, heat gun, or heat lamp to speed up the drying time of the wood. Be cautious of temperature changes when working outdoors, as condensation can occur.

Now, you are ready to start sanding. Sand both sides of the wood to eliminate any flaws that could become issues later. Start with a coarse grit and work your way up to a finer grit to achieve a smooth finish. Use a sanding block and work with a circular motion to ensure an even finish. Pay special attention to the edges and corners, and be sure to eliminate chalking, blistering, and flaking. Once you are done sanding, clean the surface to remove any remaining contaminants.

After sanding, it is time to apply the sealer. You can use a brush, roller, or sprayer for this step. Follow the manufacturer's instructions carefully and allow the sealer to dry completely before moving on.

If you are using an epoxy coating, you will need to mix the epoxy resin and hardener. This step can be messy, so be sure to have rags or paper towels on hand to clean up any drips or spills. Apply the epoxy in the middle of the wood and work your way out, making sure to get into all the nooks and crannies. Start with a thin coat and ensure it is watertight. You will need to apply multiple layers, allowing each layer to dry completely before adding the next. Inspect each layer for runs and make sure they are consistent for excellent waterproofing.

Once all the layers are dry, lightly sand the final application to create a smooth surface for the paint to adhere to. Clean the surface again to remove any dust or contaminants.

Now you are ready to start painting. Typically, four coats of paint are needed to shield the epoxy from sunlight and maintain its colour. Apply the paint with a brush, roller, or sprayer, following the manufacturer's instructions. Allow each coat to dry completely before applying the next and inspect for runs, sanding again if necessary.

By following these steps, you will have a waterproof and pristine finish on your wooden boat, protecting it from water damage and prolonging its lifespan.

Using a marine sealer

When choosing a marine sealer, opt for a professional-grade product specifically designed for marine use. These sealers provide the strongest protection and longest-lasting results. Additionally, select a sealer that reflects UV rays rather than absorbs them to protect your boat's wooden surfaces from fading and cracking.

The application process for a marine sealer typically involves several steps for the best results:

• Preparation: Gather all the necessary materials and tools, and cover the work area with a tarpaulin. Ensure the wood is clean and free from any contaminants, such as oil, grease, wax, or mould. Use acetone with a clean rag or paper towel for effective cleaning, and remember to work in a well-ventilated area while wearing a mask and safety gloves.
• Drying: Before applying the sealer, ensure the wood is dry. You can use a fan, hairdryer, heat gun, or heat lamp to expedite the drying process. Be cautious of temperature changes to prevent condensation.
• Sanding: Sand the wood on both sides to create a smooth surface and remove any flaws. Start with a coarse grit and gradually move to a finer grit. Use a circular motion for an even finish, paying close attention to edges and corners. Remove any chalking, blistering, and flaking. After sanding, clean the surface thoroughly to remove any remaining contaminants.
• Mixing and Application: Mix the epoxy resin and hardener from your chosen marine sealer according to the manufacturer's instructions. Apply the mixture with a brush, working from the middle outwards and ensuring you reach all nooks and crannies. Start with a thin coating and make sure it is watertight.
• Curing: Allow each layer of epoxy to dry completely before applying subsequent layers. Curing should be done in a dust-free room to prevent particle contamination. Depending on the product, curing times can vary from 16 to 20 hours or longer for stronger sealants. Avoid direct sunlight during the curing process, as epoxy is not UV-resistant.
• Final Sanding: Once the epoxy has cured, use sandpaper with finer grits (10-grit, 150-grit, and 220-grit) to lightly sand the coated surface. Pay extra attention to edges and corners to avoid damaging the epoxy layers. This step removes any shiny coating that may interfere with the epoxy's adhesion.
• Painting: Apply a waterproof paint designed for marine use, such as those recommended in the previous section. Typically, four coats of paint are needed to provide adequate protection and maintain colour. Allow sufficient drying time between coats and inspect for runs, sanding again if necessary.

By following these steps and choosing the right marine sealer, you can effectively waterproof and protect your boat's wooden surfaces. Remember to re-apply the sealer as needed, typically every 20 years or when signs of wear or damage appear.

Varnishing

One of the key functions of a sealer is to protect the boat from UV damage. The sun can cause the wood to fade and crack over time, so it is important to choose a sealer that will reflect UV rays rather than absorb them. A good sealer will also help to protect the boat from water damage, which can cause the wood to swell and rot.

The first step in sealing a wooden boat with varnish is to clean the surface of the wood and sand it down to create a smooth surface. You can use a variety of different grits of sandpaper, starting with coarse grit and working your way up to fine grit.

After the wood is sanded, you can apply the varnish. This can be done with a brush, roller, or sprayer. It is recommended to apply a thin coating first to ensure that it is watertight. Once all layers are applied, check for runs and make sure each layer is consistent for excellent waterproofing.

The number of layers applied will depend on the type of wood and the intended use of the boat. For porous wood, more layers may be necessary to prevent the wood from absorbing water. In general, it is recommended to apply four coats of varnish to shield the epoxy from sunlight and keep its solid color.

After the varnish has dried, it is important to inspect the wood regularly for any signs of waterlogging or rot. Depending on use and conditions, the wood may need to be resealed every 20 years or so to maintain its condition and prevent future water damage.

Using epoxy resin

Epoxy resin is a standout choice for sealing wood on boats due to its versatility and durability. It is a versatile adhesive made from a mix of resin and hardener, boasting high strength, excellent adhesion, and resistance to water, chemicals, and impact.

When using epoxy resin on wood, it is important to ensure the wood is dry and free of any oily or waxy contaminants for optimal adhesion. The epoxy resin can be applied as a coating on its own or combined with reinforcement materials such as fibreglass to create a stronger, more durable bond.

One of the key advantages of using epoxy resin is its ability to cure quickly. Marine epoxy becomes touch dry within 24 hours and reaches a rock-hard cure 48 hours after pouring. However, it is important to note that epoxy resin is temperature-sensitive and will take longer to cure in cooler temperatures. The ideal curing temperature is between 70°-80°F (21°-27°C).

Epoxy resin is an excellent choice for sealing wood on boats as it provides a durable, maintenance-free finish. It does not shrink after curing and can be used for bonding, laminating, and coating. Additionally, it is a versatile, waterproof material that can be used on boat hulls and other items frequently submerged in water, providing long-lasting protection.

When using epoxy resin, it is important to calculate the correct amount needed for your project. Epoxy resin is typically sold in starter packs or larger quantities, depending on the size of your project. By following the instructions and allowing for adequate curing time, you can ensure a proper seal and protect your boat from water damage and rot.

Sealing with oil

Another option is to use an oil/varnish mixture, often referred to as "Danish oil". This mixture offers the aesthetic benefits of oil with greater durability. You can make your own by mixing equal parts oil, varnish, and turpentine. Apply with a rag, wait 20 minutes until it becomes tacky, then rub off any remaining finish. After 24 hours, apply another coat. Four to five coats applied over a week will result in a soft, lustrous finish.

It's important to note that oil finishes are the least labour-intensive but also the least durable. You can expect to need to reapply an oil finish every few months. Additionally, while some decay-resistant woods such as teak, cedar, and oak can be left unfinished, most boat owners prefer the enhanced grain sheen of an oil or film finish.

Frequently asked questions