Topmusicanswers
Too much rosin will make the bow feel stickier as it moves across the strings. Excess rosin can generate a cloud of rosin dust as you play, and the sound will be harsh and scratchy. Rosin debris will fall onto the surface of the instrument and, over time, can damage the varnish and the wood.
How do I know if my bow has too much rosin?
Acoustically: you shall strike the bow across the strings as a test. If the bow does not slide easily and produces no sound or only a faint, thin sound, then the bow hair does not have enough rosin. But if the bow is very scratchy, then it may have gotten too much rosin.
How long should you rosin your bow?
In most situations, you'll only have to rosin the bow per 3-5 hours of play time. People with stringed instruments that have thicker gauge strings like basses, cellos and even violas, will probably end up rosining their bows a little more frequently than violinists.
