Use shoe goo, not CA, not hot glue, it works great and holds up pretty good too.

I use a Deans Speed Jig to build my packs, it's the best jig out there and is fairly inexpensive too. Just goop the shoe goo on one side of the cell, and line them up in the jig. Once you're done soldering the bars on, they'll be held together tight enough to let the shoe goo dry in that position.