#1 epoxy.
I know you didnt ask, but i'm offering this advice anyway so that hopefully you have the best chance at success, especially with a close to final size pc with not much room for error.
#2 and just as important, make sure that both pcs are center drilled before glueing back together. glue and wrap the hell out of it. Theres more than a better chance that when you glue and wrap it, the pcs. wont be totally true to one axis. so when still wet, stick it between centers and turn it slowly so you can see where its wobbling at the splice, bump the high spots with your palm until it looks like you have got it turning as true as possible. you can hold a marksalot up againts your tool post near the splice and just barely touch off...this will give you witness marks as to where the high spots are.
"other advice would be to make sure you don't have any excess epoxy all over it as the lathe will sling all over you and the lathe"