Hair spray, contains, a lacquer, or something like that. that is why, hair is stiff. when sprayed with it. I have used it on my fletching, years ago, when I bow hunted.
A Friend of mine used it, and it worked pretty well. Where I hunted at the time, was interspersed with thick brush, and semi open areas. In the early morning, the bushes where soaked with heavy dew. Don't know how it would work on bow strings, but at first it would, till the string was flexed, and the lacquer cracked.
Wayne