Ok, so what I have really isn't whiskey barrels but round wooden planters shaped like half barrels. Anyhow, taping up the liner seams with seam tape didn't work. It still leaks. So I'm giving up using liner sheets and going with a sealant. Anyone know where I might be able to get a product called "Pond Shield" locally? Seems perfect to seal my wooden pots with.
http://www.pondarmor.com/index.htm