I was going to take my boat to a welder that has done some work on my boat in the past but I came across this aluminum brazing rod stuff. Looks to me like it would be a good fix and I wouldn't have to take my boat anywhere. I have a couple small leaks where I used JB Weld in the past.
Here's the website. What do you all think?
Repair & Weld Aluminum with Propane Torch - Aluminum Weld