It is probably best to use a decent marine epoxy, not just any epoxy. There are a number of epoxies available: MAS, System 3, West System ...
For a small repair like what you are looking at I'd suggest getting a small starter kit like this one: West System Handy Repair Pack
or this slightly larger pack: West System Maxi Repair Pack
Some of the local hardware stores near me have begun to carry the West System products, so you might find these kits nearby.
West System also has a good diy instruction web page:
WEST SYSTEM | Use Guides