I strung David’s broken guitar tonight. Then I tuned it, all the while watching the epoxy joint. It held up just fine!
Unfortunately, I can still see where the crack is, so it’s not a perfect repair job. But it is fully functional now. I expect the repair job could be perfected if I were willing to sand down the affected area and refinish it, but I’m pretty sure that with my finishing skills (or lack thereof), that would make it look worse rather than better. It would benefit from a bit of steel wool though, because I did manage to get plenty of epoxy on the outside of the joint. I rubbed most of that off yesterday while it was still somewhat resinous, but since I didn’t get it all off, the finish is still a little dull. Still, you’d have to know that it had been broken to notice any of this, and in my book, that’s a successful repair.