"Designed originally for boots worn by hunters and outdoor laborers (loggers, for example), Sno-Seal is a waterproofing product with a large following. It carries one drawback: If applied to the leather used in nearly all modern leather hiking boots, those boots cannot be resoled, says cobbler Dave Page.
"You just can't work on the boots after it's on the leather," Page says of Sno-Seal. "Most hiking boots today are made of dry-tanned leather that uses chromium salts and chromium sulfates. Modern uppers sit down on top of sole units and are glued on, not stitched. To get soles to stick to the glue line, you have to be able to get the leather absolutely clean.
"Sno-Seal, Mink Oil, Neatsfoot Oil are all products that work fine as waterproofing, but they're formulated for oil-tanned leather--leather from 60 years ago," Page says. "There's just something that's in Sno-Seal that gets impregnated in dry-tanned leather. I don't know what it is. Once it's in there you can't clean it out and the leather will just not accept adhesives."
Not every hiker considers resoling their backpacking boots. If you deeply love a pair of boots and anticipate a lifelong relationship with them, though, it's best to bypass Sno-Seal. "I think Sno-Seal is an awfully good waterproofing product," says Page, who does not carry Sno-Seal in his shop. "It works fine if as long as you put it on boots that you don't care if they ever get resoled."
Has anyone used Sno-Seal and tried having a pair of their boots resoled after using it? I'm curious, as I want to keep these boots for a long time to come.