HUMIDIFYING A GUITAR
What is the best way to humidify my guitar?
Before making the decision to humidify an instrument, it is important to make sure that the surrounding environment is indeed dry enough to make this step necessary. Radio Shack sells a humidity and temperature gauge for $25–$30, which can be put into your guitar case or mounted adjacent to wherever your guitars are normally stored. Look at it every day for a week. Ideally the room would be at 45–50 percent RH with a temperature of 65–70 degrees Fahrenheit.
The point is that you can’t do this by the seat of your pants. If you don’t know how dry it is, you can’t very well decide whether or how best to humidify. Some people throw half potatoes into their cases to humidify their guitars. Others make their own humidifiers out of sponges and plastic soap dishes with holes drilled into them. Commercial humidifiers range from tubular rubber and sponge inserts to plastic-enclosed porous clay tubes. The goal of all of these objects is to evaporate their stored water over a period of days.
If you leave your guitars outside their cases, you will need to humidify the room or the whole house. Inside the case, any commercially available humidifier will do a good job. For a very dry instrument you will need to keep the case closed for a number of days to allow the humidifier to do its work. Please remember to keep an eye on the Radio Shack gauge, so you’ll know whether you’re over- or under-humidifying. Otherwise you’re flying blind, and it’s easy to damage your instrument by going too far in either direction.
Also keep in mind that the greatest damage is usually caused by radical changes in the guitar’s environment. While temperature fluctuations might lead to finish crackling and crazing, which—although often permanent—is relatively harmless, extreme changes in humidity are most often responsible for structural damage.