I'm having a problem with my bowing lately. The bow seems to slide on the strings without grabbing. This happens no matter how much rosin I apply (Carlsson). Although it seems to go away when I first apply massive quantities of rosin. I can envision 3 possibilities. 1) the bow needs to be re-haired 2) it's hot and the rosin is gunking up the bow hair causing the bow to slide or 3) the Obligatos are entering some state where they are frictionless. It's become incredibly irritating and I'm looking for suggestions. Let me say that I was able to get a consistent tone until a few weeks or so ago. Now, I'm off to practice.