TAYLOR GUITARS TECH SHEET/PAGE 1 O f 2
Symptoms of a Dry Guitar
Photo 1. Dry guitar with an unadjusted neck. The guitar
became “dry” due to exposure to low humidity. After weighing it on a gram scale, we found its total “dry” weight to be
2,162 grams. It appears to have a defective neck.
Photo 2. Dry guitar with the neck adjusted straight.
However, because the guitar body has not been humidified
yet, the bridge still sits below the correct plane of the neck
angle. Notice how close the strings are to the fretboard.
Re-humidifying the body will cause the top of the guitar
body to swell, the bridge to rise, and ideally the string
action will be back to factory specs.
Photo 3. The same guitar properly humidified and with
the truss rod correctly adjusted. A Dampit was installed
inside the guitar, which was placed in its case for four
days. The case was opened only to re-wet the Dampit.
The guitar again was weighed on a gram scale. Its total
weight now was 2,187 grams, indicating a weight increase
of 25 grams (.90 ounces of water). Note: Two Dampits often
are used simultaneously for very dr y guitars.
o environmental condition can do more
damage to your instrument than low rela-
tive humidity (RH). Many areas of the
N
U.S. experience naturally low humidity all year long.
The Rocky Mountain region, for example, has notoriously low RH levels, as do Phoenix, Reno, Las
Vegas, and a number of other cities. In most regions
of the country, however, low RH levels accompany
the onslaught of winter, mostly due to the effects of
artificially heating our homes and buildings.
If you’ve read the various references to humidityrelated problems published in our quarterly newsletter, Wood&Steel, you know that the colder months
wreak havoc on acoustic guitars made of solid
wood. As the weather turns wet and temperatures
free fall, there is a natural tendency to crank up
indoor heating units. Unfortunately, what many
don’t realize is that heating a room forces the rela-
tive humidity down to a level that poses a real
threat to quality acoustic guitars by literally
drying them out. The bottom line regarding dry-
ness is that if your guitar is not kept within a comfortable range of 45-55% relative humidity, it will be
in danger of cracking. We strongly recommend the
use of a soundhole humidifier, along with a digital
hygrometer to accurately measure the humidity
level where you store the guitar. (Please consult the
Taylor Tech Sheet, “Using a Guitar Humidifier,” to
determine how often to re-wet the soundhole
humidifier.) The following information will detail
the adverse effects of dryness on guitars, the characteristic indicators of severe dryness, and the steps
one can take to counteract those effects.
Occasionally, we get a call from a customer who
is convinced that his guitar has a bad neck. He will
cite specific problems, which may include a huge
hump at the 14th fret (on pre-NT necks) and
strings that are extremely close to the frets. The
strings “buzz” when played in the high registers,
but it would seem that raising the saddle enough to
rectify the problem would result in an uncommonly
high saddle.
In such cases, we immediately recognize that
the guitar has “dried out,” thus causing a number
of related problems: The arch in the top sinks,
taking the bridge with it; the neck bows forward, necessitating a truss rod adjustment;
and the fingerboard shrinks in width, causing
the sharp ends of the frets to extend beyond
the edge of the neck.
Combined, these events can make a guitar look
like it has a badly made neck. Actually, the neck is
fine — the problem is with the body, and that can
be corrected with a truss rod adjustment and the
use of a soundhole humidifier. However, many
customers still find it hard to believe that so simple
a solution as humidifying the body will fix what
appears to be a grave problem with the neck. Let
us convince you.
When we make a guitar, the wood first is dried,
“seasoned,” and acclimated to a certain moisture
content. As a result, all guitars leave the factory in
the same condition, and all will react more or less
the same when exposed to changes in humidity.
Our factory is climate-controlled to maintain a
temperature of 75 degrees and a relative humidity
of 47 percent. This consistency causes the wood to
equalize at a specified moisture content. As the
wood’s moisture content changes, so does the size
of the wood. Spruce, in particular, shrinks and
expands a tremendous amount as it gains and loses
moisture. For example, let’s say we condition a
spruce top in a room that is 47 percent RH, and
then cut that spruce to a width of 16 inches. If we
then were to lower the room’s RH to 30 percent, that
same piece of spruce would shrink to 15.9 inches in
width — shrinkage of almost 1/8 of an inch! If,
instead, we were to raise the room’s RH to 60 percent, the spruce would swell to 16.06 inches, an
expansion of almost 1/16 of an inch.
Relative humidity is not an arbitrary matter. We
prefer 47 percent RH because it is a very “normal”
or “median” humidity. When built at that RH level,
a guitar can be exposed to more or less humidity
and still perform well. The more extreme the temperature and/or humidity fluctuations, the sooner
the guitar will be adversely affected.
The good news is, your guitar can be protected
from many changes simply by storing it in its case.
If it does become too dry, both its moisture content
and its shape can be restored by exposing it to
humidity. A soundhole humidifier accomplishes
this very well.
Now, study the accompanying photos of a guitar
that was sent to us by a customer. A soundhole
humidifier and a truss rod adjustment were all that
was required to reverse this disastrous situation.
Copyright 2010 Taylor Guitars. All Rights Reserved.
SYMPTOMS Of A DRY GUITAR TAYLOR GUITARS TECH SHEET/PAGE 2 O f 2
Additional Information
Look for symptoms of drying
in the areas indicated
A dry guitar can exhibit
6
2
5
some or all of the following
1
symptoms:
1. Low action. Strings are
very close to the fret-
board .
2. Hump on fretboard where
neck joins body.
3. On NT necks, a slight gap
around the fretboard
extension.
4. Sunken top across the
3
4
7
soundboard between
bridge and fingerboard.
5. Back of guitar looks very
flat when it is dried out.
6. Sharp fret ends extend
beyond the edge of fret-
board .
7. The plane of the neck
angle on a dry guitar hits
above the top of the
br idg e.
We recommend using the Humidipak® system by Planet Waves
(available through Taylorware) to maintain a guitar at its proper
humidity levels. However, to re-humidify a dry guitar, we recommend
the Oasis or multiple Dampit brand humidifiers. (We recommend
using two Dampits to revive a dry guitar.)
If using Dampits:
BE SURE TO SQUEEZE EXCESS WATER FROM THE DAMPITS
AND WIPE THE OUTSIDE DRY. THEY SHOULD NOT DRIP
WHEN HELD VERTICALLY. IF DRIPS OCCUR, SQUEEZE MORE
WATER OUT UNTIL THEY STOP DRIPPING.
Insert the humidifier(s) in the body of the guitar, put the guitar
back in the case, and close the lid. It usually takes three days to see
results, but you can check the guitar daily for improvement.
The guitar described in this Tech Sheet was very dry and required
three applications of two Dampits over a period of nine days to
restore it to the correct humidification.
It is possible to over-humidify a guitar. As the arches in the top
begin to be restored, proceed with caution and check daily.
A soundhole humidifier will restore the body. It will also affect the
neck, but to a lesser degree. The frets may remain sharp, and may
need to be filed.
Store Owners and Managers
If a proper humidity level is maintained in the store, the guitar will not
become dry in the first place, thus precluding any need for repair work. The
humidity level should be kept at about 50 percent RH. It is easy and affordable
to humidify a store, and there are professional people who can help you
accomplish the task. We’d be happy to assist in putting you in touch with the
right people.
The relative humidity within your store will vary from area to area, according to changes in temperature. If you have high ceilings, do not display your
solid-wood acoustic guitars up there, where heat accumulates. Instead, put
them lower, where the temperature is more normal. Keeping them away from
outside doors will help protect them from the drying effects of weather. There
are inexpensive ways to de-stratify the temperature layers in your building.
Feel free to call us for advice on this matter.
One final note: Please instruct your customers to store their guitars in their
cases. The case will protect the guitar from most of the ravages of low
humidity.
1980 Gi l l e s p ie Wa y • el Ca j o n , Ca 92020-1096 • 800-943-6782
Copyright 2010 Taylor Guitars. All Rights Reserved.