Scarfing the hull panels

I purchased the Mill Creek Kit, which consists of the plans and all the materials for the kayak itself. This means all the plywood, other wood solids, epoxy resin, fiberglass and other miscellaneous hardware and parts for the boat. All the panels are pre-cut by a laser guided cutter at the factory. This is great because this ensures that all the panels are cut correctly, which would be no easy task if you needed to cut out all these shapes yourself. Maybe I’ll try that on a future project. Since the kayak is 16.6 ft long, the plywood that is shipped in the kit is obviously in smaller pieces. In some cases, you need to join together up to three pieces of wood to form the resulting panel for the kayak. The kit uses joints called scarf joints for this. These joints are angle cuts with epoxy resin and silica mix to glue them together. Some packing tape is used to keep the appearance of the joints clean. The hull panels consist of a bottom panel and two side panels (sheer and bilge). There are panels for both sides, so the end result is 5 panels in total. The sheer and bilge panels each come in three parts, which are glued together with the scarf joints.

The panels should be laid one on top the other to ensure the joints are even and matching. Panel alignment is said to be “fair” when the joints are evenly spaced across the joint. My table was very helpful in this step. I was able to use a string line attached with screws at the ends of the table. I was also able to tack the panels down prior to gluing with the epoxy to ensure nothing could get out of alignment. The other option if I did not have the table would be to glue them on the ground. This would be more error prone if I attempted this on my concrete garage floor.

I’m going for an all wood or “bright” finish, so it will look like a nice piece of furniture. Due to this, I used packaging tape around the joints to prevent leak outs and getting my epoxy/silica mixture on the outside of the joints. This would show up in the finish.

I used some cinder blocks to hold down the joints during drying. The joints need a good 24 hours to cure. I tried to keep the temperature at least 70 degrees with my lights.

The bottom of the kayak is delivered in two pieces and must also be jointed together by scarf joints. The two sections resemble triangles that must be glued together on one of the sides. Since this is the bottom there are no sides to match like the hull panels. The key in assembling the bottom is that the two pieces are glued together in a perfectly straight, true manner. A string line is run ‘end to end’, ‘tip to tip’; of the bow to stern and used to mark the middle of the panels before the joint is glued. The end points are tacked down after you ‘dry fit’ the joint to keep it all true. As with previous scarf joints, packing tape is used to keep the epoxy in the joint and off the surrounding wood. This is not a clear epoxy so it would show on the finish. Things will look cleaner if I keep it in the joint. Plastic is used below to prevent the bottom from accidentally getting glued to the table. Another piece is used over the top to prevent the clamp board from getting glued on also. For this joint, a long scrap board is laid over top and used to clamp down on the joint. This is done by the use of screws to clamp down on the joint. This joint is considerably wider than the previous one’s I’ve done.