I make my own gaskets from garlock gasket material but after looking at some other materials after you brought this up I did find a neat read:
http://blog.parker.com/top-three-des...emi-protection

Thanks fellas...great info...I have a new tank that I will be installing at some point in the distant future on my MA... I'll keep all that in mind..already bought the cheap moeller sending unit with the rubber gasket so I'll try that sealer...good luck on the tank RC it seems that removal and inspection is in order ? I have a 25year old tank in my egret that I wonder about...however the tanks were built with .125 ga and triple coated epoxy so hopefully it will be ok for a while...

strick