Depends what you are gluing! Epoxys are different, and can be very different. If you want laminations that don't delaminate, or a glued on riser for a board bow that won't lift, use the best quality. Some brands just don't cure hard enough and will cause problems. In their defence they were never designed for the stresses in bows, but more static purposes such as gluing up tabletops, or boatbuilding etc.
I have had a splice start to come apart with 24hr hardware store epoxies, most have been fine though. Also had a bow delaminate during the first decent bend when floor tillered, with a brand of boat building epoxy. Plenty of riser lifts with standard grade epoxies. There are so many different brands, and formulas, you want one that dries to a rock hard glue line, no rubberyness. Smooth On is reputed to be trouble free, for bow applications of all kinds. I have never used it because in Australia we have Techniglue, which dries rock hard and I have had no troubles with it so far.
