At your local Home Depot, Lowes, or auto parts store you will find a apoxy made for fuel tank repairs. I have used several brands and they all seem to work well. Dont forget to rough the area up with sand paper prior to applying apoxy. JB Weld also works great. You may need to let the apoxy set for 10 to 15 minutes after mixing prior to applying. This will let it thicken so it wont dripp down.