daytripper writes:

Traditionally, it's called "ferrule cement". It comes in a stick, you heat it
up until its nice and gooey, smear a healthy amount on the rod then seat the
ferrule (or tiptop) and wipe away the squeezings before it cools down.

That it can be released via heat (using a small alcohol lamp) can be handy, if
you have to extract a broken piece of rod from within the ferrule/tiptop...

Sounds like exactly what I want -- thanks.