Reinforcing Your Boat: Patching Aluminum For Longevity

Aluminium boats are susceptible to leaks, which can be caused by rivets, corrosion, or damage from rocks or bullets. While welding is a common method for repairing these leaks, it can be costly and may not be suitable for all boat types. As an alternative, epoxy products have gained popularity for boat repair, offering a long-term solution that reinforces the boat's structure and aesthetics. This text will explore the process of using epoxy to patch an aluminium boat, ensuring a sturdy and seaworthy vessel ready to navigate the waters with confidence.

Using epoxy to patch holes

Epoxy is a great way to patch holes in an aluminium boat and can restore the boat to its original functional and aesthetic quality. Here is a step-by-step guide on how to do it:

Shape and Clean the Metal

First, get the hull back to its original shape by hammering out the torn aluminium or using an auto-body or bucking dolly. You can cut away torn edges to help the aluminium lie flat and, to reduce the chance of cracking, drill stopper holes at the end of each tear.

Then, soften the edges of the aluminium with 120-grit sandpaper and use a coarse bristle disc to remove paint, inside and outside, to create a sound bonding surface area. Finally, abrade the surface with 80-grit sandpaper. Now your surface is prepared for the repair.

Make the Patches

Cut a single piece of #743 280g/m2 Episize Glass Fabric for the outside and three pieces, in diminishing sizes, for the inside. Try to allow for two inches of overlap around the hole to give your materials space to bond.

Prepare the Canoe and Patches for Bonding

Brush both surfaces of the canoe with the G/flex 650 epoxy, taking care to work the adhesives into the scratches and dings. A thickened mixture of 406 Colloidal Silica with the residual adhesive can help to fill any small holes and cutaways you may have around your repair.

To prepare the patches for bonding, lay the pieces on plastic and wet them thoroughly with the G/flex 650.

Apply the Patches

First, apply the single patch over the outside of the hole and smooth it into the thickened mixture. Next, stack up the three inner patches, squeegeeing them to make sure no air is trapped, and centre them over the hole on the inside. Once the stack of patches are in place, squeegee over the area lightly to remove any air.

Finishing Touches

When you are happy with the placement and shape of your repair, leave it to cure overnight. The following day, ground the edges of the patches to remove any roughness and apply the mixture of G/flex 650 and 407 Low-Density Filler to fair the patches inside and out.

Finally, once the fairing mixture has cured, apply a mix of 503 Grey Pigment to help camouflage your repair. After letting your repair cure completely, you’ll be ready to test your canoe on the water!

Welding as a repair method

Welding is a reliable method for repairing an aluminum boat, especially when compared to epoxy, which is a temporary solution that may fail at any time. Welding creates a metal-to-metal bond that is strong and long-lasting.

Aluminum boat welding requires specific tools and expertise. It is important to select the right welding equipment, such as a MIG or TIG welder, to ensure a stable wire feed and reduce the risk of contamination. The welder must also be designed for aluminum to achieve solid and clean welds.

Before welding, it is crucial to properly prepare the aluminum surface by thoroughly cleaning it to remove any dirt, grease, or oxide layers. This step ensures a clean weld pool and prevents contamination that can lead to weak welds. Additionally, controlling the heat input is essential due to aluminum's high thermal conductivity. Using short welds and allowing the material to cool between passes can help avoid warping or burn-through.

For most marine-grade aluminum, filler materials such as 5356 and 4043 are commonly used. It is important to choose a filler that complements the base material to ensure compatibility and strength.

When it comes to repairing an aluminum boat, it is always best to seek the services of a professional welder or a specialized boat repair shop. They have the expertise and equipment to ensure quality results and can handle various metals and projects with precision.

Using a riveted patch

If you have a hole in the hull of your aluminium boat, one way to repair it is to use a riveted patch. This method is a proper way to repair the hole and can be a long-term solution.

First, you will need to source a patch of aluminium that is slightly larger than the hole. It is recommended to have a quarter or half-dollar-sized piece of aluminium. You will also need a permanent sealer, such as 5200, and some flat washers and a sealant if you want to add extra security.

To prepare the surface, you should clean and sand the area around the hole. This will ensure that the patch adheres properly. Cut the aluminium patch into the desired shape, allowing for a 2-inch overlap around the hole. Drill some stopper holes at the end of each tear to reduce the chance of cracking. Softening the edges of the patch with sandpaper and removing any paint with a coarse bristle disc.

Now you are ready to attach the patch. Place the patch over the hole and secure it with rivets. Make sure that the rivets are tight and not loose, as this could cause leaks. If you are using a sealant, apply it to the hole before riveting the patch in place.

As an extra precaution, you can also apply a layer of epoxy or marine putty over the patch. This will help to fill in any small gaps and create a smooth finish.

With this method, you can securely patch a hole in your aluminium boat, ensuring that it is safe and seaworthy for your next outing.

Temporary fixes

• Using a small piece of aluminium and JB Weld steel to fix the hole. This should hold for several years.
• Using epoxy putty to seal the hole. First, flatten the area around the hole with a hammer, then sand or grind the area and clean with acetone solvent. Mix the two-part, marine-grade epoxy putty by rolling equal parts of A and B together until the colour is uniform. Then, press and smooth the putty into the hole and the surrounding area, from both sides if possible.
• Using a nut and bolt with flat washers on both sides and some sealant.
• Using a product called Marine Tex, which is specifically designed for marine repairs.

For small holes, you can also use JB Weld or buy a pack of fibreglass fibre and a can of fibreglass resin. A little resin, a small piece of cloth, and some more resin over the hole on the outside and inside will seal it well.

Long-term solutions

Welding

If you can find an experienced welder who works with aluminium, they may be able to spot weld the holes shut. However, this method can be costly and may not be suitable if your boat has a lot of holes.

Marine Epoxy

Marine epoxy is a long-term solution for repairing holes in aluminium boats. It can provide a strong, permanent fix if applied correctly and can even help to camouflage the damage. Here's a step-by-step guide to using marine epoxy for boat repair:

• Shape and clean the metal: Use a hammer or an auto-body/bucking dolly to get the hull back to its original shape. Cut away any torn edges and drill stopper holes at the end of each tear to prevent cracking. Softening the edges of the aluminium with 120-grit sandpaper and remove paint with a coarse bristle disc. Finally, abrade the surface with 80-grit sandpaper to prepare for bonding.
• Prepare the patches: Cut a single piece of #743 280g/m2 Episize Glass Fabric for the outside and three pieces in diminishing sizes for the inside, allowing for a 2-inch overlap around the hole. Lay the patches on plastic and wet them thoroughly with the epoxy.
• Apply the patches: Brush both surfaces of the canoe with epoxy, working it into scratches and dings. Mix colloidal silica with the epoxy to fill any small holes. Apply the outer patch first, smoothing it into the thickened mixture. Stack the three inner patches and squeegee them to remove air, then centre them over the hole on the inside. Squeegee lightly to remove any remaining air.
• Cure and finish: Leave the patches to cure overnight. The next day, ground the edges of the patches to remove any roughness and apply a mixture of G/flex and low-density filler to fair the patches inside and out. Once cured, apply a mix of grey pigment to camouflage the repair.

Fibreglass Patches

Fibreglass patches can be used in conjunction with G/flex epoxy to repair holes in aluminium boats. Cut a single piece of 10 oz Episize Glass Fabric for the outside and three pieces in diminishing sizes for the inside, allowing for a 2-inch overlap around the hole. Wet the patches with G/flex epoxy and apply them to the inside and outside of the hull, smoothing them into the thickened mixture. This method provides a strong and flexible repair that can withstand the pressure and knocks that your boat may encounter.

Frequently asked questions