Epoxy is NOT going to hold a surface that has not been 'prepped', as in roughing it with an abrasive of some kind. And that means ALL surfaces to be bonded, ferrule, shaft, and inside of hosel. Shafting epoxy is not wood glue, where the glue penetrates fibers and actually becomes part of what has been bonded, when cured/dried. Strip the paint from the shaft completely, equal to the depth of the hosel + (min.) 1/2 the inside of the ferrule.
For total geeks, nerds, and those that want to know "why did my head fly off the shaft", "why did my ferrule creep"..............( gawd, I just hate exposing this side of me😉)
http://www.mereco.com/resources/ask-the-doctor/what-makes-epoxy-resins-good-adhesives-why-do-they-bond-so-strongly-to-surf
The surface energy of the substrate may be changed (raised) by careful surface preparation, e.g. roughing, chemical etching, solvent cleaning, plasma treating.
I might add that I only use Brampton's quick set epoxy! iirc, I've built over 16 different golf clubs in my lifetime😉 and may have had 1 creepy ferrule, mainly due to the fact the ferrules were a bit oversized to begin with(DTG). But they were prepped according to Hoyle. Cannot ever recall a flying head, of my own clubs, nor of anyone that may have acquired a club from me.