SIGNS OF SEVERE DEHYDRATION

Under normal conditions the top is slightly convex. In the above picture (of a guitar which has been severely de-hydrated) you can see that the top has collapsed and there is a definite hollow in the guitar top. In this case the hollow measured almost 3/64 of an inch deep. This means that the top has flattened, then collapsed further to a bowl shape. In some cases you can see the top ripple over the struts. Because the bridge is glued at cross grain to the top, when the top and the bridge shrink the stress of the opposing tensions releases the glue joint. Though some may look at this picture and feel that the bridge lift is the most sever issue, it is in fact the collapse of the top which is most worrisome because it may not recover fully when re-humidified. If your guitar shows any of the above signs seek help immediately

The picture above illustrates another classic sign of severe de-hydration, normally accompanying the collapse of the top. What is occurring as the top collapses is that the section of the Fretboard that extends over the top is collapsing with the top into the Soundhole. This is evidenced in several ways which can include a hump in the fingerboard between the 14th-16th fret resulting in buzzing (see the picture below), a visible opening between the Fretboard and the top, and the development of cracks in the top on either side of the Fretboard.

Another classic symptom of de-hydration is the fret-ends protruding from the edges of the fingerboard as it shrinks. The Fretboard is made from ebony and will expand and contract, whereas the frets are unaffected by humidity changes.

Visible Fret Protruding

Cracks beside the fingerboard due to shrinkage - If you look closely you can actually see a few distinct signs of dehydration in this picture. You can obviously see the cracks, but also look closely at the Fretboard binding. You can see how the shrinking of the fretboard has cause the binding to warp around the fret-ends. If you look closely at the black rosette ring, you can see that it is raised above the surface of the top. The soundboard shrank, the rosette stayed in place.

The guitar is constructed with the braces glued at cross angles to the top and the ends seated in the kerfing that runs around the inside of the body. The binding is installed into a stepped edge routed in this kerfing. As the guitar continues to shrink due to severe lack of humidity, the ends of these braces (Which are shrinking in an opposite direction) push the binding off the body as pictured above. The guitar is disassembling itself as it shrinks. Just as the bridge shears off as the top collapses, the braces sometimes shear off as well. You can sometimes hear the rattle of the loose braces. This occurs most commonly on the back braces.

The cracked top in the above picture is the symptom of dehydration which commonly alerts an owner to the guitars' dehydrated state along with sharp frets and buzzing. By the time the guitar is in this condition many of the other less visible symptoms may also be in occurrence. A cautionary note: If your guitar cracks, try to avoid touching the crack which your bare hands as the oils from your skin can cause more extensive damage and cause the crack to be more visible after refinishing. Dirt or oils, as well as hesitation in having it repaired immediately may impact the effectiveness of the repair.

The Good News

The above guitar shows the correct arch to the top and correct positioning of the fingerboard. It is the same guitar which was used to illustrate the bridge lift / collapsed top / fingerboard lift earlier in this document. The guitar has been rehydrated for 2 days at this point. Many of the problems have corrected themselves as the guitar assumes it's normal condition. The recovered arch of the top is clearly evident as well as the reduction of the hump in the fingerboard as it returns to normal. Any portion of the instrument which has broken due to it's shrinkage will obviously require further repair. I.E. The bridge and the bracing.

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