It’s that time of year again when thoughts turn to autumn foliage, down jackets, and crackling fires—or to ice cream, flip-flops, sand and surf, depending on what corner of the world you call home. But while you’re busy switching out your summer and winter wardrobes and covering (or uncovering) your patio furniture, you may want to pause a moment to consider your trusty guitar. A change in season demands a lot of it. Like you, the guitar acclimates to its environment. Sudden variations can stress it out and cause a host of physical damage such as warping, cracking, and chemical deterioration. When it comes to the guitar and weather, the rule of thumb is not to expose your instrument to any climate conditions that throw you yourself out of whack.
Most guitars are made of thin pieces of solid or laminate wood that are glued together. Environmental factors like temperature and humidity directly affect your instrument and can contribute to its decline, even its complete ruin. When wood loses moisture, it shrinks. Conversely, when it gains moisture, wood expands. While gradual changes in temperature and humidity will generally not harm a well-made guitar, extreme temperatures can wreak utter havoc. The goal should always be climate stability. It is generally accepted that the ideal conditions for a guitar is air humidity that is neither too high nor too low, thus somewhere in the 45-55% range, and temperature that is kept between 65-75 °F.
Temperature on its own is less damaging to the guitar than humidity (although it does affect the amount of moisture that air can hold.) Wood is generally tolerant to changes in temperature, and for the most part it expands and contracts together. Extreme temperatures, however, can cause serious damage, especially when combined with extreme humidity. Heat weakens glue. Cold chills lacquer and can cause “crazing,” a network of fine cracks in the surface or glaze of the guitar.
Never expose your instrument to extreme temperatures for long periods of time. Leaving your guitar in a car on a frosty night or on a blazing hot day is a surefire way to completely destroy your instrument. Also keep the guitar out of direct sunlight as much as possible as it makes the wood more brittle and can fade the color of the instrument.
Humidity, on the other hand (that is, the amount of water vapor or moisture in the air), is most dangerous to an instrument. You should strive to avoid significant changes in humidity. When wood gets wet, the cell walls become softer, making wood easier to bend. Often the strings themselves are enough to bend the neck. A guitar that absorbs too much moisture through high humidity expands and swells. This distorts the geometry of the instrument and, consequently, its tone and playability. Telltale signs of a "wet" guitar are high action, a swollen top, fret buzzing in the high registers (as fretboard rises with the top), distorted back and sides, muffled tone and low volume, finish cracks, and bindings that are separating.
On the flip side, 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, room or household humidifiers may be necessary to maintain a proper environment. Telltale signs of a "dry" guitar are lowered action, fret buzzing and lifting, fret ends sticking out from the fingerboard, dips in the top or back, and cracks in the finish and/or wood.
In addition to the damage that temperature and humidity can cause your guitar, they can also affect your strings, especially nylon strings. Introducing your guitar into a different environment will almost always automatically detune the strings. Other areas to watch for temperature-related damage are any glued joints, like where the neck meets the body, or where the fretboard is attached to the neck. High temperatures and humidity can weaken these joints and even cause them to fail.
While you can’t control the weather, you can control your instrument’s environment to a great extent. Here are some other simple pointers to help protect your guitar:
• Keep your guitar in a case when you’re not playing it or when you travel with it. There are two main kinds of guitar cases: gig bags and hard cases. Gig bags are light to carry and provide a good amount of protection. They do not, however, protect against temperature changes very well. Hard cases, on the other hand, provide excellent protection against temperature, humidity, and physical damage. Hard cases are also essential for taking a guitar on an airplane or on long journeys. Be sure to give your guitar some time to adjust to the environment before you take it out of its case. By storing your guitar in a hard case and allowing it to change temperatures inside the case, you're controlling the temperature change. It's going to take much longer for the outside temperatures to warm up the exterior of the case and penetrate all the way to the guitar or bass. The reverse is also true. If the entire case is one uniform temperature, heat is going to be gradually expelled from the inside out. The outermost areas of the case will cool first, followed by the loss of heat from the middle of the case where the guitar is. This will happen gradually and help to protect your guitar.
• 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. You can also purchase a guitar humidifier for pretty cheap to do the job. (Guitar humidifiers that fit inside the sound hole or extend into the body can be very effective but must be used with great care to avoid water damage. Check with a professional before using them.)
• 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. Your guitar can even be subjected to extreme temperatures while in the passenger or back seats. Remember to allow your instrument time to warm up slowly before opening your case after being transported in a cold vehicle, and time to cool down after a ride in a hot car. Again, abrupt changes in temperature can cause finish crazing.
• When traveling cross country, keep in mind changes in local humidity and protect your guitar accordingly.
While we’re on the subject of seasonal change, you might want to use these transitional periods to tune-up your guitar, beginning with a string change. Although you really should be changing strings more often than every six months (assuming you play on a regular basis), a change of season is always a good excuse to throw on a new set. Full sets of strings should be replaced at the same time. If you only replace one string, the others are likely to break soon, the strings will have different tones, and the opened pack of strings will begin to corrode. When changing a set of strings, some guitarists recommend replacing them one at a time, rather than removing all the strings at once, to maintain tension on the neck.
Changing guitar strings is also a good time to clean your instrument. Don’t use furniture polish. Ask your guitar store for the best cleaning solution for your particular guitar’s finish type. If you’re up to it, you might want to unscrew the pickups and pickguard so you can really get in there for a thorough cleaning. You may be surprised by how much dirt you find. You should also give the fretboard and headstock a good once-over with a clean rag because fretboards in particular can pick up a lot of sweat, oils, dirt and grime from your fingers. Just be careful not to damage the fretboard wood by cleaning too vigorously.
Clean all metal parts of your guitar with a good metal cleaning compound. Chrome and nickel are notorious for corrosion and tarnish, particularly in certain environments, so setting up a regimen to clean your pickup covers, bridge, and tuning mechanisms will help in maintaining the visual appeal of your instrument.
You can also use this time to tighten up any screws that have worked themselves loose, and to correct any intonation and truss rod issues. No matter how well you take care of your instrument, the truss rod will need adjusting regularly, and the intonation screws on the pickups will need to be adjusted to ensure that you’re getting the balanced sound you want from your guitar. Your guitar may also need bridge adjustments. If you’ve never tackled these repairs on your own before, you may want to enlist the help of a professional to show you how it’s done. In fact, a yearly checkup for your guitar is just as important to the instrument’s upkeep and maximum playability as an annual physical is in keeping you fit and vibrant.
And one final tip on keeping your guitar in superb shape—play it every single day. Just as a muscle will atrophy with disuse, so will a guitar deteriorate.
While weather can be a guitar’s worst enemy, knowing how to combat it will help to protect your beloved instrument. With a little weatherproofing, you can extend the life of your guitar and ensure it will play the same throughout your lifetime.
Photo Credit: PhotoAtelier, Uploaded from http://flickr.com/photo/22501424@N00/6335287821