Bows and weather

March 12, 2019, 9:45 PM · 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!

Replies (8)

March 12, 2019, 9:48 PM · Looser with humidity increase, tighter under dry conditions.

Best of luck.

Edited: March 13, 2019, 5:22 AM · 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).
Looked at another way, I have seen a bow stick snap during a rehearsal because that same air conditioning dried the hair so much that it over-tensioned the bow stick - and the violinist had not paid attention while this happened.

Another factor - if a "soft" bow stick has too much hair for the stiffness of the stick, the hair can deform too much under the pressure of playing. The proper amount of hair in a bow should be a function of the stiffness of the stick - more hair for a stiff stick than a soft one. For a cheap rental bow from a regular music store, the bow was probably haired at the point of manufacture with some standard amount of hair for all the bows they make - and probably with a different climate than where you live.

Proper bow action depends on proper tensioning of the bow stick (some straightening of the stick combined with just the right amount of stretching of the hair).

The amount of "play" in a bow's tightening mechanism is not sufficient for all climates. At some point in my life I was sending my bows from the California desert to Norman, OK for rehairing and the climate difference was really too great for a completely adequate rehairing job. I even had the same problem with several bows I bought from SHAR in Michigan.

March 13, 2019, 5:24 AM · "Driedy-tighty". ;-)
March 13, 2019, 6:21 AM · 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.
March 13, 2019, 7:18 AM · Yes, it's a temperature and humidity. Since it's a rental, just exchange the bow.
March 13, 2019, 9:44 AM · Thank you so much. It's raining today and barely playable. I think it must have been haired during the polar vortex!
March 13, 2019, 10:07 AM · Traditional dial-type hygrometers use a hair for humidity measurements for this reason (contracts in dry weather, expands in damp).
March 13, 2019, 10:22 AM · 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.


Facebook Twitter YouTube Instagram Email

Violinist.com is made possible by...

Shar Music
Shar Music

Yamaha Violin Finder
Yamaha Violin Finder

Pirastro Strings
Pirastro Strings

Corilon Violins
Corilon Violins

Dimitri Musafia, Master Maker of Violin and Viola Cases
Dimitri Musafia, Master Maker of Violin and Viola Cases

Metzler Violin Shop
Metzler Violin Shop

Los Angeles Philharmonic
Los Angeles Philharmonic

Gliga Violins
Gliga Violins

ARIA International Summer Academy

Bay Fine Strings Violin Shop

Bobelock Cases

Fiddlerman.com

Fiddlershop

Nazareth Gevorkian Violins

Los Angeles Violin Shop

Pluhar Violins

Potter Violins

Pro-Am Strings Ltd

Violin Lab

Violin Pros

Wangbow Violin Bow Workshop

Subscribe