Bulkhead 17 sits about a foot and a half ahead of the transom. I cut all of the framing members with the aid of a chop saw; this gave me a very precise fit. The top member is supposed to sit between the side rails according to the plans. I decided to make this piece a bit longer and join it to the sides using a simple lap joint, which is much stronger than the butt joint in the plans.

Here I am using a router to cut the lap joint. You notice that I have placed a clamp at the back edge of the routed-out cut. This is to prevent the router bit from tearing out a chunk of wood as it gets close to the edge. I was able to glue the other end back together with epoxy. Yes, another "oops."

My first lap joint ever--and it looks beautiful! I just wish I knew how to make these when I put together Bulkhead 11.

I bought a specially formulated cold-weather epoxy that mixes at a volume ratio of 4 parts resin to 1 part hardener. After I fit the pumps to jugs and primed them, I figured that it would be very difficult for me to measure out appropriate parts of each as these liquids are very viscous (thick). I had read somewhere that another builder used a scale to get accurate measurements, so I got myself a scale.

Here is the plan: Measure the mass of the container, then pump in the amount of resin needed and note the total mass. Subtract the mass of the container from the total mass to get the mass of just the resin. Multiply the mass of just the resin by 0.25 to figure out the 4:1 ratio to the hardener. Last, add the calculated mass of the hardener to the original total for both the container and resin. Set the scale to this final mass, which will cause the balance beam to bottom out. Pump in just enough hardener into the container (as it sits on the scale) to bring the balance beam up to level. You will now have the perfect 4:1 ratio.
NOT SO FAST, MISTER. Yes, I used this ratio for the epoxy on this bulkhead. However, when I started to get ready to work on the transom, I realized that the hardener was much thicker than the resin, and perhaps its mass relationship might be different. I called RAKA, the company that supplied the epoxy, and they reported that the correct mass relationship was 100:22. I can deviate on the plus side by 10%, and still get acceptable bond strength. I am only over that by 0.8%. Nuts. The important things to remember are that the mass and volume mixing ratios will most likely be different, and using a mass ratio is definitely more accurate (see transom for some craziness).

Now here is the typical boat builder's picture where everything is all glued and clamped up. Just like with Bulkhead 11, I used 1-inch stainless screws to fasten the fir to the plywood, pre drilled, of course. My collection of clamps has definitely grown. There is supposed to be a 6-inch high access slot cut across the lower part of the bulkhead. I'll wait until the transom is framed up before I cut this out.