Bows and weather
Can someone remind me about whether bow hair gets tighter or looser as temperature and humidity increase? We have a fractional rental bow for my youngest that was fine when it was 10-20F and proportionately dry. Now that it is in the 40s and more humid the bow won't tighten enough. It's playable but the hair is hitting the stick in forte. Since it is a rental, I can just exchange it, but I just wanted to make sure it is likely a weather thing. I swear I am exchanging rental bows practically every 3 months for one reason or another!
Looser with humidity increase, tighter under dry conditions.
The change in hair length with air moisture (humidity) change is really significant. When I had rehearsals in a hall with significant refrigerated air conditioning and loosened the hair at the end of rehearsal, by the time I looked at my bow hair in the violin case at home the next morning the hair was hanging in a catenary curve like the cables of a suspension bridge - my home was cooled with evaporative cooling (in the California high desert where my home was maintained at 50% RH, the outside RH could get as low as 5% and the refrigerated AC could further dry the air).
So glad this topic came up! I had some odd things happening with my bow tension last night while practicing and couldn't figure out why.
Yes, it's a temperature and humidity. Since it's a rental, just exchange the bow.
Thank you so much. It's raining today and barely playable. I think it must have been haired during the polar vortex!
Traditional dial-type hygrometers use a hair for humidity measurements for this reason (contracts in dry weather, expands in damp).
My bow did this once, and my luthier just undid the frog, and gave the mechanism inside the frog a half turn. He had told me to come back to reverse it when the weather warmed up and got more humid.