Quote Originally Posted by yodofizzy View Post
I can attest to the effectiveness of this method. About a year ago I made a backpacking tarp that I used nylon fabric to make. It wasn't waterproof, though, so I used a mixture of gasoline and silicone caulk to waterproof it. The gasoline does in fact evaporate and leaves behind a slightly heavier, waterproof, silicone impregnated nylon tarp. The nylon was not adversely affected in any way, and I am pretty sure this works for wool too. (I tried it on a few other fabrics and one of them was a scrap from an old wool blanket)

Hope this helps
I did the exact same thing with a nylon tarp I made for my camping hammock setup. It's a fairly easy process, although it must be just "just so" in order to be effective. The end result is a sort of thin rubbery silicone coating that will shed water.

Unfortunately, I don't think this would be at all advisable on a wool kilt.