Cold crack repair

I recently purchased a royalex mad river courier with some cold cracks near the thwarts. The gunwale is vinyl and I was wondering if it’s necessary to drill out the rivets and remove the gunwales for a full repair. If so is if possible to reinstall the gunwales after or will the holes be too large to rivet?

The second option is to leave the gunwales on and chisel out the cracks and do the repair with epoxy.

I don’t plan on using any fiberglass reinforcement since the cracks are only 3-4 inches long.

Anyone have experience with either strategy? Thanks!

I would leave the gunwales in place. You should use West System G Flex epoxy for the repair.

To increase the bonding surface area for your epoxy you need to gutter out the crack on both the inside and outside surfaces. The instructions that come with the G Flex epoxy describe this process pretty well. I use a Dremel tool with an appropriate bit, but you can use a cabinet scraper, narrow wood chisel, or some other device if you don’t have a rotary tool.

If you have an electric drill and a hacksaw blade start as follows. At the bottom of the cold crack drill a hole about twice the diameter of the crack itself to terminate it. Using a smaller bit, drill a series of holes that abut each other until you have widened the crack sufficiently to get your bare hacksaw blade through it. Then you can run the blade up and down to uniformly widen the crack. Then gutter it out on both sides to an approximately 45 degree angle to the surface of the hull.

Clean the area well using denatured alcohol after washing. Back up the crack on either the inside or outside with clear packing tape. Turn the boat on its side and apply your G Flex to fill the crack on that side. Sometimes you need a second application to completely fill the crack. When the epoxy has cured to the point it won’t run or sag, repeat the process on the other side to fill any remaining unfilled crack. You can sand any overfill off fair and flush after the epoxy cures.

Find some paint that closely matches the hull color and paint the epoxy on both sides to protect it from UV damage.

Thank you! Project starts tomorrow!

If you do not already have G Flex, search for and buy the 650-K kit. Ignore the fact that it is titled “aluminum boat repair kit”. The kit comes with 4 ounces of unthickened resin and 4 ounces of hardener but also includes silica powder which you can add to your mixed epoxy to create a stronger “epoxy glue”. The kit also comes with a couple of dental syringes with drawn out tips which are useful for filling cracks. You can use them to inject a little epoxy into the crack where the gunwale covers it on the inside and outside.