Acoustic Guitar Bracing Repairs

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Acoustic Guitar Bracing Repairs

What Is Bracing?

A Martin Guitar With The Back Removed Showing The Top Bracing

In an acoustic guitar, bracing is the internal support structure that holds the instrument together. By design, the top back and sides of the body are made of thin pieces of wood that resonate when the instrument is played.

Without sufficient bracing to reinforce it, the instrument would fall apart under the substantial force put upon it by the strings.

An ideal bracing pattern supplies support and stiffness where required, while retaining some flexibility so as to focus the tone, and amplify the sound, of the strings.

What Causes Bracing To Fail?

While an insufficient application of glue during construction or a bad batch of adhesive are certainly possible, in our experience, humidity damage is the primary culprit behind bracing failure. 

Since the inside of an acoustic guitar generally does not have a protective finish like the outside, it is particularly vulnerable to the effects of humidity. Swelling and contracting of the wood can cause a brace to crack or the glue joint to fail.

If the bracing becomes loose or damaged, it is important to repair it quickly in order to prevent warps or cracks in the in body and keep the instrument sounding its best.

Repairing Guitar Bracing

Bracing repairs are made complicated by the need to work inside of the closed guitar body. Not only is it a cramped space, but much of the work must be done partially “blind” while working through the soundhole. The nature of the task typically requires an array of lights, mirrors, inspection cameras, clamps, jacks, cauls, spatulas, etc.  

Loose / Lifted Bracing

A Martin Guitar with A Loose Back Brace

Under stress, the glue joint connecting the brace to the body can fail. Most often it presents near one or both ends of the brace. In rare cases, a complete failure causes the brace to fall off entirely!

Besides the risk of damage from a loss of structural support, loose bracing can produce sympathetic rattling as it vibrates against the body during use.

Diagnoses of loose bracing can be tricky; They are not always easy to spot. Extremely loose braces sometimes produce an audible sound when the body is tapped. However, all braces must be inspected individually with a spatula to confirm the extent of the damage.

In our experience, if a loose brace has been found, it usually has company. Unfortunately, the nature of working through the sound hole does not lend itself to multitasking; Loose braces typically need to be glued individually.

After protecting the surrounding area and cleaning the gluing surface as well as possible, glue is worked underneath and the brace clamped back into position. The excess glue is then wiped clean.

This work is delicate. The braces themselves are soft and prone to denting. Furthermore, failure to properly support the instrument during clamping can cause more damage than it repairs!  Special care must also be taken to keep the work looking clean.

Working Glue Under The Brace With A Spatula

Cracked Braces

A Martin Guitar with A Cracked Back Brace

A cracked brace typically occurs because the wood that it is made of is trying to warp, but a strong glue joint is preventing that from happening. Instead, a weak point in the wood succumbs to the pressure first and splits.

Cracked braces can be identified visually with a lighted inspection mirror. While cracked bracing is a bit easier to identify than loose ones, they are quite a bit less common.

Once a cracked brace has been identified, it must be reglued to restore strength. After protecting the surrounding area, glue is worked into the crack before it is clamped in position.

This work is delicate. The braces themselves are soft and prone to denting. Furthermore, failure to properly support the instrument during clamping can cause more damage than it repairs!  Special care must also be taken to keep the work looking clean.

Using a Repair Jack To Clamp The Brace
The Completed Repair

About Guitar Repair Long Island

Guitar Repair Long Island is the area’s premier destination for fretted musical instrument care and maintenance. Led by owner/head technician Erik Salomon, the shop is dedicated to providing quick, honest, and reliable service. Our vast experience in all aspects of instrument repair ensures that we can help with whatever your needs are. Contact us with any questions or book your appointment today.

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