I need help from the post whore thread. I have a bunch of steel gas cans that I want to fill while the gas is cheap, however, most of them weep around the bottom seam. Not enough that it leaks off the shelf and onto the floor, but enough that if I fill them my garage smells like gas fumes. I know there is a product that you can pour into a tank to fill cracks. I used it on a motorcycle tank when I was a kid. I know probably half the people that post in here know what I should use. I don't something that gets rock hard if I can avoid it though. Any tips?