We may not want to admit it yet, but fall is here in the Upper Midwest. The nights are cooler (or downright cold!), the air is drier, and here or there the leaves are starting to take on their fall colors. It’s a time of change.
This time of change will affect the guitar owner. The primary change that the guitar owner needs to pay attention to is the humidity. The moisture, or lack thereof, that is in the air. We need to consider humidity because of how it affects the wood that our guitars are made of. If you’d like to read about the details of how moisture (humidity) affects wood, I found this great paper for you to read. For those of you who don’t have a spare hour to read and absorb all 26 pages, here’s one quote that will be the foundation for the rest of this blog post:
“Moisture content changes of only a few percent are sufficient to cause significant shrinking and swelling of wood”
In the fall, the air tends to dry out..the humidity drops. Also, as it gets colder, we start to turn our furnaces on, which dries the air out even more. A room that may have been at 50% relative humidity, can drop down to 30%, 20%, or even less as we run our furnaces more. So, in the fall and into winter, we are dealing with a potential wood shrinking problem, because the wood is losing moisture. How does this affect our guitars specifically?
-Sharp fret ends: as the wood in the neck of the guitar shrinks, the metal frets stay the same size. This can cause the ends of the frets to protrude beyond the edge of the fretboard. Because the frets are beveled, they are sharp on the ends, and we can feel that as we play the guitar.
-Too much neck relief: The shrinking (drying out, remember!) neck wood can also lead to the neck contracting toward the pull of the strings. This will cause your string height to be higher near the middle of the neck. Usually a simple truss rod adjustment will fix this issue.
-Fret Buzz: On acoustic guitars with solid spruce tops, the top will also shrink a bit and “collapse” a little. This can lead to string height that is too low and you can get fret buzz, particularly on the upper frets. Some players have a winter saddle and a summer saddle. The winter saddle is higher in order to compensate for the shrinking top.
-Cracking: This is probably the worst problem you can encounter when the humidity drops. The top of an acoustic guitar is held in place around its rim by “kerfing”, as well as by a series of “braces” connected to the inside surface. These braces to a great job of strengthening the top, but they also keep it from moving much with humidity changes. If the change in moisture content is too great over a short period of time, the wood can tear itself apart trying to move within the constraints of the bracing, creating a crack.
1. The first solution to all these moisture and humidity changes has been done for us by the guitar manufacturer: the wood is mostly sealed by a finish. All guitar finishes, whether they be simple shellac, lacquer, or some type of modern polyurethane, help slow down the moisture content changes in the wood. They don’t stop it, but they slow it down, which is good, because it gives the guitar time to acclimate to its surroundings. So, if you keep your guitar in a nice, humidified environment, but have to play a gig in a dry environment, the change won’t affect your guitar immediately, or at all, depending on how long you are there.
2. Control the environment. Well, that’s a little broad. We need to control the environment in which our guitars reside for the most time. In the winter, this means we must add moisture to the air surrounding our guitars via a humidifier.
You can humidify a guitar case, a showcase, an entire room or even an entire house with various humidifiers. It is really up to you. The key is to keep the humidity at around 40 to 50%. Guitars, and people for that matter, are the most comfortable in this humidity range.
My recommendation is to keep guitars in a hard case with some kind of humidifier made for guitars. The hard case makes for an easy to humidify space. I prefer the Planet Waves guitar humidifier for its simplicity, ease of use, price and quality construction. You must remember, though, to keep the humidifier filled with water, or it won’t be doing anything!
*I am now a Planet Waves dealer and you can purchase the recommended humidifier directly from Tree Strings. I keep them in stock!
To sum up: changes in relative humidity are coming fast! Keeping your guitar in a stable environment of around 40 to 50% relative humidity will go a long way to increasing the life of the instrument and keep it playing the way you like.
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