Big Jim nailed it…. I’ve been using G-10 for I beams for many years, and I have had more than my share of slight separation or cracked finish. This happens at the back of the shelf mostly, but has happened in other locations too. But…. The stuff is incredible for strength, and I refuse to stop using it.
Even when your wood is bone dry, shipping it to a different climate than it was built, humidity can and will cause the wood to move and no finish you use makes a difference. I’ve had most my issues sending bows to very dry climates like Utah, Co, AZ, NM…. Also Australia is seriously dry climate. Etc…etc… from Oregon. The wood in my shop stays right at 12% year round. Sometimes dropping to 10 in late summer. I lay up most my risers ahead of time and let them dry in my spray booth that I keep heated and dry.
I’ve had my best luck staying below 10% on the I-beam lay up, and then hanging it in the spray booth at 90 degrees for a couple days after it’s been shaped and before I finish it. If it’s going to separate a wee bit, it typically does so prior to finish and the crack can be filled with epoxy before finished. I seldom have issues doing it this way…..but I still have them come back for refinish now and then. But…. I can live with it, and my customers love the mass weight and the non flex riser.
All the bows I built here with G-10 in the riser that stays in Oregon, or the west coast, I’ve never had an issue…. Kirk