Well, i had the joy of being 4th in line for SF camp. and here are the exact spawn times from time of death to respawn:
28:44, 29:15, 32:22, + 36:15
Maybe from Server reset it's possible 19 hours, but from my experience and most everyone else on 7th hammer he's a 26-38 hours spawn. no one has seen him pop at 19 hours, and we maintain a pretty solid list, and it's respected by most. Most being operative. After Server reset whoever was on camp gets to keep it. Again, the 19 hour spawn time seems to be bogus. If anyone since LoY release has seen him pop at 19 hours, post here. Thanks