Darel,

I am working on my first build also. I believe that I have experienced exactly the same type of scarf joint failure, which you described. I was using Titebond II with WRC strips. When I examined the failed joints I determined that the failures were mostly due to glue starvation in the joints (as several other responses suggested). Although I have a fair amount of woodworking experience, I have very little previous experience working with WRC. WRC is a very absorbent wood species compared to most of the other woods that I have used, even more so when you are not dealing with end grain. Once I started adding more glue to the joints and giving the joints adequate drying time (say 12 hours), the problem went away.

I brace my joints (both butt and scarf) by placing a short section of WRC (about 3-inches long) coated with Gulf wax, over the front and back of the joints, and clamp it together with 2-3 spring clamps. The overlapped short waxed sections of WRC serve both to align the joints and keep the spring clamps from denting the strips. I have used this method for long sections off the boat (to make scarf joints on the garage floor), and for butt joints on the boat between station forms. Most of my strips were B&C, once these joints are surrounded (encapsulated) by the adjacent strips the joints become very strong.

Good Luck with your project and I hope this helps you out.

Greg N.