I've got a hole about the size of a #2 pencil in my aluminum boat that allows it to take on water at a pretty decent rate. My "fix" was to jam a plastic grub in the hole backed with an old rivet, but that is only a temporary solution.
I'd like to find a DIY solution for patching holes in aluminum that will last a good amount of time and not cost me a ton of money. My first thought was to try some soda cans and JB weld... but I know nothing about that stuff. My second thought was to use Bondo, but I just don't know.
We used to scuff up the aluminum real rough and put a fiberglass patch on it. It would probably work even better with today's epoxies. We actually patched the oil pan from a crane engine with fiberglass!
A #2 pencil size hole like a new pencil about 6 or 7 inches long !!!
Get a bolt that fits that hole, coat it with some 3m5200 and tighten it up.
For other holes or leaks we suggest that you re-buck the rivets and use gluvit on the rivets and seams. It is a penetrating epoxy designed for that.
For serious large holes get a piece of aluminum (fairly thick) something like a piece of an aluminum street sign (hint hint) coat it with gluvit and rivit it in place or use 3m5200.
Use only stainless steel bolts and aluminum rivets when working with an aluminum boat. Do not use regular steel or any pressure treated wood since they will react with the aluminum.