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There is a very easy fix for something like this although not it is not "proper".
However it works.
To do the repair you need to be able to clean the metal all around the crack/hole a half inch or so. Once it's clean cut a piece of 100% cotton cloth (think Tee shirt material) in a shape that will cover the area. With your thumb and forefinger saturate the cloth with silicone caulk and cover the area pressing it on to make good contact but not squeezing out the silicone. The patch is best if it isn't thick but the material still needs to remain saturated with the silicone.
I've used this technique many times on many things and it works rather well. Matter of fact I did this on the upper tank of my AA close to ten years ago now and it is doing just fine.
If you use black cloth and black silicone it won't be very noticeable at all.