I am not sure when it spit, but I know I let the joint bond over several weeks before bending it on the boat. I don’t think any one element caused the failure, but here are my suspicions in order of potential culpability:
- Did not wet out joint with thin epoxy before adding the thickened.
- The joint may have been clamped too tightly thus squeezing out too much epoxy.
- Mixing ratios of the e-glue may have been off, it is tricky to measure 50:50 when the A and B parts differ so greatly.
- Position of scarfe. Why oh why did I put the scarf at the place of greatest twist and tension!? The stern quarter really kicks up on an NIS.
Regardless of what actually happened, such failures fill you with doubt. I have had great success with traditionally thickened epoxy; whilst mixing it seems to take an age, you can be sure it is mixed. This e-glue worries me.
I have spent some time researching my worries about the e-glue, and I have yet to hear a concern from anyone, so I have relaxed and continued to use it but with attention to the ratio and wetting out of joints first.