I fixed my aluminum jon boat that had rivet leaks with 2 hammers,an 8lb. sledge and a 4 lb sledge. I had tried everything to put over the rivets to fix the leak and nothing worked. If you can get to both sides of the rivets hold the 8 lb on one side(just hold it against the rivet don't brace it) and tap the other side a couple of times with the 4lb. It works I used to just keep my minners in the bottom of the boat now I have to use a bucket.