I have been spraying Thompson's Water
Seal on my dry flys it seems to repeal the water well, and really doesn't
effect the hackle. I got the idea when I saw a commercially made product
in the fly shop, but was way more expensive than a can of Thompson's. I
also have used it on the outside of my waders from time to time to stop the
leaks. I can't find any diffinate hole in the waders, but Thompson's works
some.