Guitar Body Cracks
Source:Crack & Brace Repair
Repair of Guitar Body Cracks:
There are many different types of body cracks that you will see in Acoustic Guitars depending on where the crack is located, the type of crack, (open or closed), the type of wood and the alignment of the crack. It takes a slightly different method to fix all of these cracks and we will address each one of them in future articles.:
Determine the Cause of the Crack:
You should make it part of your job to determine the cause of the crack. This way you can convey your findings to the instrument owner to prevent future costly repairs. Here are some of the causes and effects:
Stress Cracks: Often caused by undue stress to the instrument. This can be by heavy gauge strings, inadequate structural design of the guitar and differential shrinkage of different materials.
Impact Cracks: Caused by a slight impact of the instrument against another hard or sharp object. You will usually see these in the side of an instrument. One thing about impact cracks is that they will usually get much worse over time due to the stress of the strings and continued playing of the guitar. It is far easier to repair the crack soon after it happens.
Another very susceptible area for impact cracks is around the bridge area of the guitar. There is a lot of stress in this area and sometimes just a slight bump, even against your knee or elbow will be enough for the top to split open.
Atmosphere Related Cracks: These are usually related to a dry conditions that the instrument has be subjected to. Quite often you will see a variety of splits in the tops, back sides and fingerboard areas. These type of cracks will open and close at different rates depending of the humidity level.
Another area to look for dryness or shrinkage related cracks is instances where a celluloid pick guard has been glued directly onto a spruce or cedar top. With age the celluloid shrinks considerably more than the top wood and you will see cracks develop at the upper and lower edges of the pick guard.
Additionally you can see cracking in back purfling due to shrinkage of the back plates pulling away at the purfling. Binding splits and separation and splits across the rings of an Acoustic Guitar rosette.
Finally, due to differential shrinkage of the fretboard to the guitar top plate, you will see cracks alongside and parallel the fretboard – these are usually within 1″ of the side of the fretboard.