ACOUSTIC GUITARS and THE DRY WINTER MONTHS
by:© Steve Carmody

   It is winter here in Silver Spring, MD. and the air is dry. Due to the seasonal drop in humidity I inevitably see more instruments coming in for cracks in the top and string buzz problems.

   Cracks caused by dry air are almost always along the grain lines in the area between the bridge and the butt end of the instrument. The soft wood between the darker grain lines shrinks due to the lack of moisture and separates from the denser and stiffer winter growth.

   In most cases these cracks can be cleanly repaired with little evidence of the repair, if the instrument is brought to a repairman as soon as it becomes apparent that there is a crack. Most repairmen charge by the inch for crack repair, so the shorter the crack the cheaper the repair. Additionally dirt and oil that works its way into a crack over time makes it more difficult for the repairman to hide the repair.

   To avoid cracks which result from seasonal drops in humidity you must always be conscious of the dryness of your home/store environment. Many people who have forced air heating have a humidifier built into their system. If you are one of the fortunate, just set it for a minimum of 45 % and you will probably never have a problem. For the rest of us there are a couple of solutions.

   Ideally an instrument should be in its case when it is not in use. This gives it a degree of protection from the room environment. Protective case covers are also commercially available to give added insulation. In-Guitar or In-Case humidifiers, when used as directed, provide adequate protection.

   If you display your instruments but do not have a built in humidifiers, there are a number of in room misters and vaporizers available. They work well when used as directed, the most important factor being that the room temperature should kept no lower that 68 degrees. A low tech solution is to put a pan of water in front of a forced air vent, or on top of a radiator.

   Additionally, you should invest in a hygrometer with a digital readout so you can monitor the humidity level. Keep it around 45 % if possible. These can range from $40.00 to $120.00. I have a $40.00 unit and it works just fine.

   Another effect that dry air can have on your guitar is to tend to flatten the top. It is not unusual to get buzzing strings at this time of year, particularly if your string action is set very low. As the top loses moisture it settles down and takes the string height over the frets with it. (Conversely, in the summer it can tend to swell the top and the string height rises). A good solution for this is to have a second, slightly higher saddle, made for use in the winter months.

   Overly dry air can also shrink ebony fretboards, causing fret ends to stick out. The solution is to file or "dress" the ends down. Shrinking fretboards can also tend to cause-bow. To remedy this, increasing the tension on the truss rod (a quarter turn at a time until the neck shows relief as viewed at around the 6th fret)may help.

   In many cases one of these measures may be sufficient to correct the problem caused by dry air. In others, all may figure in to your problem and need to be addressed. So do not be surprised if your friendly repair person suggests minor fret work, neck adjustment, and saddle shimming (or a new saddle, which some may prefer). Better yet, keep your guitar well protected from seasonal environmental changes by maintaing proper humidity!