I've used "Shoo Goo" with great success. I think the fact that it remains pliable helps maintain adhesion through the multiple thermal shock cycles better than a rigid epoxy.
Ya, you want an adhesive that is at least partially flexible. I've used urethane construction adhesive with good success and it's available at any home improvement store.
No don't use hot glue - temp cycles will definitely undo it fast.
I think I have seen a product called GOOP in the hardware stores that might work. But I might be tempted to try bathtub silicone (type 2).
GOOP is pretty similar to shoe goo and is a flexible and waterproof. Its usually sold in a blue tube and works great. I use this stuff on a lot of things, highly recommend it!