Using Adhesive Sealant on an Aluminum Boat

When patching leaks in the hull of an aluminum boat, adhesive sealant is required to make sure the patch doesn’t leak. Below is a list of tools and materials you will need to patch holes up to three inches in diameter in an aluminum hulled boat.

Required Tools and Materials

All of the required tools can be purchased at your local hardware store, along with the aluminum stock, while the sealant will come from your local boating supply store.

  • Drill
  • 1/8 inch drill bit suitable for metal
  • Pop rivet gun
  • One package of 1/8 inch pop rivets
  • 100 grit sandpaper
  • Tin snips
  • 3m 5200 Adhesive/Sealant™
  • Cleaning compound or solvent

Step 1: Surface Preparation

The process of sealing a leak in the hull of your aluminum boat is easy. It involves placing a piece of thin aluminum stock over the opening and sealing it. Both surfaces must be ready to accept the sealant. Read the label on the container and use the recommended cleaning solution to remove any grease, oils or other contaminants from the surface of the hull. Use the 100 grit sandpaper to rough up the surface of the metal surrounding the hole.

Step 2: Drill Holes for Rivets

Using the tin snips, cut the aluminum stock large enough to overlap the leaking area by a minimum of one inch. Hold the patch over the hole or leak and drill holes one and a half inches apart all around the patch and through the hull. As an example, a one inch hole will require a minimum patch size of two inches square. Each side of this patch will require three holes, one at either corner and one in the middle.

Step 3: Apply Adhesive/Sealant to Both Sides

Once the rivet holes have been drilled, remove the patch from the hull and coat both the patch and the hull with the adhesive/sealant product. Make sure that the adhesive applied to the hull covers more area than the patch to ensure a good seal. For added strength of the bond and the seal, coat the rivets prior to installation as well.

Step 4: Apply the Patch

Once the hull and the patch are well coated, apply the patch to the hull and line up the holes for the rivets. Make sure the rivets are well coated and install as many rivets as required to maintain the one and a half inch spacing.

Step 5: Overcoat Patch and Rivets

Once the patch is riveted in place, you need one more coating of sealant to make sure you have a strong seal. Liberally coat the joint area around the patch and all rivet heads. This will ensure the strongest seal that will last as long as possible.

Step 6: Allow to Cure

The final step, and possibly one of the most important, is to allow the adhesive to fully cure. If you don’t allow the sealant to cure, it could wash or peel off and the leak will continue. If the leak is allowed to continue, serious damage may occur to your boat.