Hello, David. Here are some thoughts that may help. First, I make sure I am using a quality golf club epoxy. Anything from GolfWorks is fine. Second, epoxy works best on clean, abraded surfaces so I make sure both the hosel and shaft tip are abraded, clean and dry. When I use acetone, I make sure the surfaces are dry. Another very important factor is the temperature in the workshop when you are mixing and applying the epoxy. The warmer the better. Most epoxy bottles say not to use below 60 degrees, but I’d recommend no less than 70 degrees. Plus, if your shop is cool in the morning and then you heat it up, remember that the epoxy in the bottles isn’t getting as warm right away. Finally, I make sure to give plenty of cure time, usually 24 hours, and again, in a warm place. If I mess up just a little bit on any of these things, the epoxy will be vulnerable.
One more thought. I have learned that it’s important to make sure there are no burrs in the hosel. They wreak havoc on graphite shafts and will cut them in two in a short time. That’s not an epoxy problem, but the head can come flying off if I haven’t made sure to remove them as part of the hosel prepping process. Long answer, but I hope it’s helpful! Michael