You no longer need it to be water proof right? You can use 100% Silicone although you should wait a week or so before returning the snake to it.
An alternative is to heat the seam up with a hair dryer and use hot melt glue smooth it with a cold spoon back and you are done wait for it to cool down and return the snake it might only take 30 min or less. It is non toxic and no out gassing. Just a thought!
A