There used to be a product called "Goodyear Plio_Bond". I had a gas tank that I chopped it to fit what I was working on. Back then someone suggested this stuff. It was impervious! . A friend of mine even used it on his custom oil pan for his car. He also had no problems with it. But I don't know the life of it and I don't know if it is still available.

!!! RIDE SAFE !!!

Keith in soggy Pa.
05 1200 custom "Lava"

 

It seems to me that as long as you keep your tank full during storage that all this tank liner stuff is unecessary, and by not using it, will save you bigger headaches down the road.

Thumper26