Making a Plywood Kayak

Step 16: Finish Work

While you have a wet brush, apply a fill coat over the whole deck. Apply masking tape on the side of the hull about 1 - 1/2” down from the sheer (1/2” below the trimmed edge of the deck glass. Then brush on an even coat of epoxy over the whole deck. If you are more comfortable making an even coat with a foam roller, feel free to do so. The goal is to build up enough resin to fill in the weave texture of the fiberglass fabric. Apply the resin over the side on to the masking tape.
Let the fill coat cure for about 1 hour before removing the masking tape.
After the deck has cured, trim off the excess cloth around the coaming and sand it smooth. Apply a fill coat to coaming then flip the boat over so you can work on the bottom. We want to do a fill coat on the bottom as well.
If you have some gaps in the glass near the stem, now is your chance to patch them and even if you don’t it is a good idea to add some extra glass in this area.
Sand away any roughness at the “bottom” of the stem.
Run a strip of masking tape about 1/2” above the sheer line.
Paint on a good fill coat over the whole hull. Then cut a two 3” x 12” strips of bias-cut fiberglass. Lay these over the stem onto the bottom of the boat to protect this high-wear area. Do the same to both ends.
After the resin has cured for an hour, peel off the tape.
When the epoxy has had a couple days to set up hard it is time to start sanding. We over lapped the fill coats along the sheer where the edge of the deck glass made a little bump. This extra resin will make it easier to mask this edge.
Use 60 grit to sand the whole boat. The goal is to make the surface of the boat smooth and level.
Sand all surfaces, but do not sand the angles at the chine and sheer yet. It is very easy to sand through these areas and we don’t want to mess up our fiberglass work.
Strive to obtain an even, matte finish over the whole boat. If you start sanding into the fiberglass, stop sanding. You will see when you get into the glass because little whitish spots in the pattern of the weave will start to appear. If you start seeing the glass and you still have shiny spots in the area, you can apply another fill coat to the whole boat so you have more material to level out the surface.
Once you get an even surface you can come back and carefully hand sand the sheer and chines.
When everything is sanded evenly with the 60 grit sandpaper, go over everything again with 80 then 100 grit. You are now ready to varnish or paint.
You want at least three coats of varnish or enough coats of paint that the paint is opaque. Use a marine-style varnish with UV protection or a exterior enamel paint. Marine boat paint is good, but a good deck enamel will work also.