link to this "blue-tac"?
Could you spray on that with no worries? Surely cutting out the letters isn't easy either?
Cutting the letters is easy with a sharp Stanley blade. That liquid mask is the stuff they use when they do RC shells and they produce some really nice clever stuff with it.
Its better than Bluetack :dead:
Aparently, you put blue-tac all the way around the lettering, pressing it firmly into any of the little corners etc, then paint with a very fine brush, or if you are feeling confident, you could always try sprayiing instead, but obviously you'd have to cover the whole bullet.
Then if I were you, I'd lacquer the whole thing.