There are a number of functions that are served by the bridge of the acoustic guitar. Not only does it set the placement for the strings by holding the strings in the body, but it also plays a pivotal role in good action, tone and intonation. As such, it is essential to have an understanding of how the bridge works and how to keep it in optimal shape and replace it, when necessary.
Not only does the bridge of the acoustic guitar hold the strings securely in the body of the guitar, it also plays a part in setting the spacing of the string. Even the smallest change in the spacing of the string can change the whole feeling of the instrument drastically. Perhaps even more vital than string spacing, the bridge of the guitar sets the intonation of the instrument. Depending on where the bridge and saddle is located, the guitar could have the ideal intonation or could be impossible to properly tune it. The position and angle of the saddle slot in the guitar bridge is instrumental to the setting of the intonation of all guitars.
In addition, the bridge of the acoustic guitar also plays a major role in setting the height of the strings or the action of the instrument. The saddle of the guitar is responsible for setting the action of the instrument by being in the saddle slot of the guitar bridge. There is a three-step process that can be used to set the action on the acoustic guitar and this can be used to lower the action on the guitar.
Furthermore, the bridge serves as a brace used for reinforcing the body of the guitar. The majority of acoustic guitar braces are located inside of the instrument; therefore, many people don’t think of the bridge as being an external brace. Internal braces assist in supporting the weight from the tension of the strings. This is exactly what the bridge does but on the exterior of the body.
Can You Replace the Bridge on an Acoustic Guitar?
Because of mishandling and normal wear and tear, there are times when the bridge of an acoustic guitar will need to be replaced. Below are some issues that could ultimately lead to the need to have the bridge replaced:
A bridge that has been loose for an extended period can become distorted. If there is significant twisting, replacement will be necessary. An insignificant amount of warp could be repaired by having the bridge heated and clamped or having the bottom planed off if the bridge is sufficiently thick.
Typically, cracks appear in two locations on the bridge of an acoustic guitar; at the edge of the saddle slot and through the bridge pin holes. You can sometimes repair minor cracking through the pin holes when there is no other issue with the bridge. Usually, it is not wise to repair cracks that are at the saddle edges because of the constant tension.
On inexpensive instruments, a neck reset is a pricy repair. To lower action on a guitar that requires a neck reset, sometimes the bridge is modified or thinned. This is because the location of the saddle is already low. When the neck on an acoustic guitar is being reset after the bridge has already been thinned, it is wise to replace the bridge to get it back to an accurate height.
Incorrect Saddle Placement
Issues with intonation caused by the wrong placement of the bridge and/or the saddle may not be corrected through repair. This could require total bridge replacement in order to fix the problem.
Fixing the Problem
If the bridge is cracked or loose, it will have to be removed from the body and re-glued or replaced. To figure it out, look at the back of the bridge and if there is a gap between the bridge and the body, it has become loose. Sometimes the gap cannot be easily seen because it is very small. In such a case, use a piece of paper to slide between the body and the bridge. If it is properly attached, the paper should not get in between them.
Once it has been determined that the bridge has to be removed, use card stock paper to trace the bridge and then cut it out of the paper. To protect the finish, the piece of paper can be placed around the bridge while removing it.
It is tremendously vital to properly line up the bridge before gluing it down or this might have to be redone. You can measure and mark the center line of the guitar bridge on the front side and bottom. This allows you to line up the center line on the guitar body with the center line of the bridge.
This is the not the only time a bridge has been glued to the instrument; therefore, bridge pin holes are already drilled in the top. You can place wooden dowels in the last and first string holes to perfectly line it up with the location of the old bridge. When the bridge has been glued on, you can drill out the dowels.
When the body and the bridge have been thoroughly cleaned, they can be clamped together without any glue; this is called a dry run. Whenever anything important is being glued onto a guitar, doing a dry run is smart. This allows you to see if the cauls, clamping idea and clamps properly fit.
Following a successful dry run, the glue can be applied. It is important to use the glue sparingly on most glue joints but the bridge is an exception to that rule. This is because it has to be attached securely to the body.
Use a paper towel or damp cloth to wipe off the excess. Ensure that you immediately wipe it away. This will prevent it from hardening and ruining the finish. For best results, leave the guitar bridge clamped together to set up overnight.
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