Repairing Baked-On Paint: Restoring Your Boat's Hull

Boats have a tough life. They bake in the sun, get soaked by the rain, and are in a constant battle with plants and creatures that want to attach themselves to the hull. This can lead to baked-on paint on the hull, which can be repaired by following these steps:

- Clean the hull with a proper boat cleaner and remove any old adhesives or stickers with a release adhesive and sealant remover.

- Use a power buffer to buff the hull and restore its quality.

- Apply a fiberglass compound to remove oxidation and stains without affecting the underlying gel coat.

- Sand the hull with sandpaper to remove any remaining impurities and create a smooth surface.

- Apply a primer to the hull and allow it to dry.

- Choose a paint that is compatible with the primer and apply it to the hull using a roller and brush.

- Allow the paint to dry completely before lightly sanding for the next coat, applying a minimum of two coats.

Clean the hull with a boat cleaner and remove any old adhesives

To repair baked-on paint on a boat hull, you must first clean the hull thoroughly. This is a crucial step as it ensures that the paint will adhere properly and endure.

Start by washing the hull with water and a boat soap or boat cleaner. Boat soap will effectively remove any wax buildup and impurities that may cause the finish to bubble or look uneven. A boat cleaner will also help to remove any dirt, grease, grime, and stubborn stains. You can use a scrubbing brush, Scotch-Bright pad, or boat eraser for this step. Remember to also wash down your work area to minimise dust and airborne particles.

Next, you will need to remove any old adhesives or stickers. For this, you can use a product called Release Adhesive & Sealant Remover. Make sure to get rid of any old adhesives as they can compromise the new paint job.

Once the hull is clean and free of adhesives, you can move on to the next step of repairing baked-on paint: sanding the hull.

Use a power buffer to restore the quality of the fiberglass

The outermost layer of a fiberglass boat is usually covered in a special resin called gelcoat, which protects the hull and gives it its colour and shine. Over time, exposure to the elements can erode the gelcoat, leaving it dull and chalky. To restore the quality of the fiberglass, you can use a power buffer.

Firstly, clean the hull of your boat as you normally would. Adding a cup of detergent to a gallon of warm water and using a sponge usually does the trick. If mildew is present, add some bleach to your detergent solution.

Next, apply a strip of polishing compound onto the surface of the hull. Then, spread the polish with your power buffer, increasing the speed setting, and slowly moving it back and forth across the surface until glassy. Finally, wipe away any excess polish.

If the polishing compound does not provide the desired results, you can use a rubbing compound, which is more abrasive. Select a rubbing compound formulated for fiberglass and use it in the same way as the polish.

After polishing, apply a coat of wax to protect the surface and improve the gloss. Use your power buffer to spread the wax evenly. Wait until it dries and gets cloudy, then buff the surface to make the shine pop.

Sand the hull with 120-180 grit sandpaper to remove any gelcoat

Sanding the hull of your boat is an important step in the painting process and requires careful preparation. The first step is to select the appropriate sandpaper grit. For removing any gelcoat from your boat's hull, 120-180 grit sandpaper is generally recommended. This grit size is ideal for scuffing up the gelcoat and removing any stains without being too aggressive on the surface.

It is important to remember that gelcoat is a thin layer, and using an extremely coarse grit can quickly cut through it. Always start with a finer grit and only increase the coarseness if necessary. Sanding with 120-180 grit sandpaper will help create a uniform surface and provide a good base for the subsequent painting process.

When sanding, use a random-orbit sander for large, flat areas. This type of sander will save you time and effort. For smaller areas or hard-to-reach spots, a palm sander or trim sander with a triangular mount might be more suitable. Remember to work in well-ventilated areas and wear appropriate protective gear, including gloves and a respirator, to avoid inhaling dust and fumes.

After sanding with 120-180 grit sandpaper, it is essential to inspect the hull thoroughly. Run your hand along the surface to feel for any dips, grooves, or imperfections. You can also use a thin batten to check for any irregularities. If you find any problem areas, apply additional epoxy filler and sand again, this time using a longer board sander with 320-400 grit sandpaper. This step is crucial to ensure a smooth finish for your paint job.

Once you are satisfied with the smoothness of the hull, it is time to move on to the next steps in the painting process, such as applying primer and undercoat. Remember, taking your time with the sanding process and paying attention to detail will result in a better final finish for your boat's hull.

Apply primer and let it dry

Now that the hull is smooth, it's time to apply primer. Make certain the hull is clean and completely free of any dust, small hairs or debris. You'll also want to spray down the area around the boat to keep dust from flying in the air. Finally, you're ready to apply an undercoat.

The undercoat should be compatible with the paint you're using. As a rule, two-part paints like Interlux Perfection are much more durable than single-part paints. But for the DIY beginner, they may prove more difficult to work with. Roll or brush undercoat paint onto the hull.

Use the same colour undercoat or primer as the topside paint (especially when painting over a dark-coloured hull). Once finished, head back and let it dry.

Yes, you heard right: more sanding... using the 300-400 grit paper. Check the smoothness again. Find any dips or holes? Apply more epoxy or a second undercoat. Ultimate smoothness equals ultimate shine.

To avoid an orange peel finish—and there's nothing worse than orange peel unless you're dealing with an actual orange—clean the hull with a solvent to remove any oils from your fingertips and hands.

Apply the paint using the roll and tip method

The roll and tip method is a non-stop, fast-moving, two-person job. One person applies a thin coat of paint with a roller, and the other follows immediately behind with a brush to remove the roller stipple and smooth out the paint. The roller should be used in an up-and-down motion, and the brush should be used side to side. This method can be used to paint large surfaces, like a boat hull, and will give pretty good results.

The first step is to make sure you have the right equipment. Use a very short nap roller, and a quality brush. Badger Hair brushes are supposedly the best, but they can be expensive. A 3-4 inch brush is best, as it requires fewer strokes, but a smaller brush is easier to control. For the roller, use a 1/8-1/4" nap roller cover.

The next step is to prepare the paint. Make sure you have the right consistency—paint that is too thick will run, and paint with too much thinner will be too thin to coat the surface.

When painting, work in small sections, around 2 feet wide, so that the paint does not dry before it can be smoothed out. The person using the roller should apply the paint as thinly as possible, with 80% or better coverage. The person using the brush should only use the very tips of the bristles, dragging them as lightly as possible over the paint. The brush should not be loaded with paint, and it should not be pressed down onto the surface.

The roll and tip method can be done in different directions. You can roll and tip horizontally, roll and tip vertically, or roll and tip in a combination of the two. The most common method for hulls is to roll vertically and tip fore and aft. This is because, if you roll and tip horizontally, you will have to blend the paint at the edges of each section. If you roll and tip vertically, you will only have to blend at the edges once, at the end of the job.

Frequently asked questions