I was getting a slow leak in my Alumacraft 1448 MV Jon. I filled the boat up with a hose and found one of the rivets was missing a head. I would prefer to replace the rivet, but it is under the middle bench seat and I am not going to take out the bench to repair. I have patched it with JB Water weld putty after doing some research. Have any of you had any experience with this product? Or any other sage advice on sealing the leak?

Thanks