By Erin Shrader
Stringed instruments are happiest given a constant temperature of 60 to 70 degrees and a relative humidity of 35 to 50 percent. Unless you’re a tropical sun worshiper, you’re probably quite comfortable under similar circumstances—where do you typically set your home thermostat in the winter? Unfortunately, such ideal conditions are virtually impossible to maintain as fall turns to winter, the heat comes on indoors, and your instrument travels from home to rehearsal, school, or concert hall through all kinds of weather.
Those who make and maintain instruments know what to expect: open seams, rattling purfling, cracks, and necks on the move (a problem that especially plagues cellos and basses).
Here’s why: Wood is hygroscopic, meaning that it attracts and absorbs moisture from the atmosphere. As it takes on moisture, wood swells. As it dries, it shrinks. One problem is that different kinds and cuts of wood shrink and swell at different rates. The most visible example is the peg that loses its grip after a dramatic change in the weather. In order to work properly, the peg and pegbox must be perfectly fit, but they lose their grip when the peg wood and the maple of the peg box change shape at different rates. Though it’s less visible to the eye, maple and spruce also shrink and swell at different rates, putting stress on the instrument.
Fortunately, there’s a built-in safety valve: the hide glue that holds your instrument together. Hide glue is used for violins because it is strong but, under stress, the glue will break, rather than the wood. The resulting open seams are easily repaired. Cracks in the wood are a more serious matter. Wood is forgiving, but it will eventually crack if it gets too dry.
Furthermore, instruments with extensive repairs, such as those with cracks repaired with cleats or patches reinforcing worn areas around the soundpost, are more susceptible to the vagaries of humidity. If your instrument has been heavily restored, take extra care to protect it.
Wood is forgiving, and most instruments survive the seasons without incident. The best way to ward off potential trouble is to avoid temperature extremes, humidity, and abrupt transitions as much as possible. Of course, perfect stability is not realistic, but here are a few suggestions that can help your instrument through the rigors of winter.
1. Get a Hygrometer
If you’re concerned about humidity, get an accurate hygrometer in order to monitor relative humidity. The Radio Shack digital hygrometer-thermometer combination that retails for about $15 has a good reputation for accuracy, or you can do a little online research for other recommendations. Small, case-mounted hygrometers are often inaccurate.
If your home or studio falls below about 20 percent humidity, consider using a room humidifier. Of course, this only works while your instrument stays in the room.
3. Case Closed
Your case is your first line of defense. Leave your instrument in the closed case as much as possible. It slows down changes in temperature and humidity. A padded case cover may help even more. Don’t hang your violin on the wall or store your cello in a cello stand. Home heating dries out the air inside your house. Furthermore, ambient air movement circulates the warm air around your instrument, drying it further, says violin maker James N. McKean.
4. Case humidifiers
A case designed to keep water out will be fairly good at keeping humidity in. Case or instrument humidifiers are popular with some players, though none of the violin makers I spoke with recommended them, mostly because they only work if used properly and it’s too easy to forget to keep them filled. A new generation of humidifiers filled with hydrogels that release vapor very slowly need filling less often. There are also new two-way humidification systems that may help with the maintenance, adding and pulling out moisture when it senses humidity levels unfavorable to your instrument. But remember, stability is the goal and once you open your case, you’ll be abruptly introducing a moist instrument into a dry environment.
5. Don’t Overdo It
Over-humidifying is worse than not humidifying at all, says Tom Sparks, who teaches violin making at Indiana University. He recalls horror stories of panicked musicians taking very dry instruments into the bathroom and running the hot water to steam up the air. Sparks recommends wrapping your instrument in silk or tightly woven cotton, a practice he picked up from the older members of the string faculty. He doesn’t have scientific evidence that it slows the transfer of humidity, but since he started keeping his own violin in a silk bag, he has not had to make any more humidity-related repairs.
Additionally, Sparks recommends building time into your schedule to arrive well before you play. Let the instrument acclimate in the case for a while, and then crack the lid and let it sit for a while longer. Slow down, have a cup of coffee. You and your instrument will both have a better rehearsal.
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Want more instrument and bow care? Try Strings’ Violin Owner’s Manual. We also offer a handy series of web guides: Care & Repair of Violins or Violas, Caring for Your Violin or Viola Bow, Care & Repair of Cellos, and Caring for Your Cello Bow.