i dont post alot here although i have been here a long time, jus readin...but i feel like i should come to ur rescue..
go to home depot..when i go to lowes they never have it...
get epoxy putty..its cement color and has the consistency of play-doh/putty. if u use a small amount and try to refrain from it gettin into the chamber when the pieces are pushed together then u should be good to go..i use that stuff to hold pieces together for bong....

when i broke my bubbler i used epoxy gel, slightly thicker than the glue, its easier to work with but can still run....make sure again to no let any get in the chamber, a few dots of it should work really well...

so depending on wha the break is like, use one of those. for all my glass work i use the gel, but the putty is much more moldable..

hope i helped