Kevin, I have used a sealant that is called pro-seal. It comes in two parts that are mixed together and is grey in color. There are various numbers it goes by depending on how fast you want it to cure. It actually is a fuel tank sealer. Its easy to use but very messy, if its out and open i always get it on me somewhere but you cant beat it. Its a PPG product and is made by Prc-DeSoto International.
http://www.ppg.com/prc-desoto/main.a...=seal&menuID=3 I hope this helps
Tony Giantonio