Re: Fixing 3" tear on side of Aluminum boat
I like TD's JD Weld idea. The dried epoxy is a medium gray color that might not match the aluminum too well, but it you sand the shiny top layer off, it turns a light gray color that will blend much better with the aluminum if you are worried about aesthetics.
The aluminum brazing rods (Durafix) would work nice too, but you should practice a bit with them before attempting a repair like this, if you want it to look good. If you braze that area you should roll the boat over so the area is horizontal as the brazing rod goes from liquid to solid quickly,,, it will run and drip off a vertical surface. Maintaining the right temp is critical since the rod melts about 100* (or something like that?) less than the aluminum base material, you wouldn't want to melt a bigger hole in the boat. All you would need is the brazing rods, MAPP gas torch and stainless steel brush,,, MAPP gas to get that big of an area hot enough, all at once. Google Durafix and watch a few of the videos.
