Proper Guitar Maintenance

Fine guitars are made of thin pieces of solid wood that are glued together. They are directly affected by humidity and temperature.

Humidity is the amount of water vapor or moisture in the air. Temperature affects the amount of moisture that air can hold. Both of these factors affect wood because it is naturally "hygroscopic". This means that it takes on and gives off water. Therein lies the challenge.

A guitar that absorbs too much moisture, through high humidity, expands and swells. This distorts the geometry of the guitar and, consequently, its tone and playability. Add high temperature, and humidity can weaken glue joints and even cause them to fail. With prolonged exposure, the glue under the bridge will weaken, allowing the bridge to pull off. Telltale signs of a "wet" guitar:

• High action
• Swollen top
• Fret buzzing in the high registers (as fretboard rises with the top)
• Distorted back and sides
• "Tubby," muffled tone, low volume
• Finish cracks
• Bindings separated

Overly dry conditions, or lack of sufficient humidity, can be equally detrimental to your guitar, causing the wood to shrink and crack. It can also cause poor tone and improper intonation. In dry regions (mountainous or desert areas) or northern climates, where heated air is common in winter, simple guitar humidifiers may not be sufficient. Room or household humidifiers may be necessary to maintain a proper environment. Telltale signs of a "dry" guitar:

• Lowered action
• Fret buzzing and lifting
• Fret ends sticking out from the fingerboard
• Dips in the top or back
• Finish and/or wood cracks

Gradual changes in humidity and temperature will generally not harm a well-made guitar. Your guitars should be kept in an environment of 49% relative humidity and a temperature of 75 degrees.


The biggest danger caused by humidity and temperature is rapid or extreme changes. That’s because different parts of the guitar shrink and expand at different rates. For example, if your local humidity drops very rapidly, the guitar cannot acclimate itself uniformly, causing cracks or failure of glue joints in different portions of the guitar as it tries to "cope" with the drying situation. The same is true, in reverse, with high humidity.

Extreme temperatures can wreak havoc, too. Heat weakens glue. Cold "chills" lacquer causing finishes to crack or craze.

While you can’t control the weather, you can control your guitar’s environment to a great extent. Here are some simple pointers.

• Keep your guitar in its case when you’re not playing it.         

 • Purchase a home hygrometer/thermometer to keep tabs on the relative humidity and temperature. Adjust your home environment as necessary. Plants and humidifiers add moisture in dry winter months. Air conditioning controls humidity in the hot, muggy summer months.
• Avoid storing your guitar near sources of hot, dry air (such as forced hot air heating ducts), or cold, damp areas (garages, basements, closets with outside walls).
• Never, ever, transport your guitar in a car trunk. Temperatures inside car trunks are extreme in any kind of weather. It’s the quickest way to destroy a guitar. Even in the passenger compartment your guitar can be subjected to extreme temperatures. For example, please allow your instrument to warm up slowly before opening your case in a warm room after being transported in a cold vehicle. Abrupt changes in temperature can cause (ie: cold guitar to warm room) can cause finish crazing.
• When traveling cross country, keep in mind changes in local humidity – and protect your guitar accordingly.
• Guitar humidifiers that fit inside the soundhole or extend into the body can be very effective but must be used with great care to avoid water damage. Check with a qualified guitar repair person before using them.