Repairing Guitar Braces

Braces- Braces reinforce and strengthen the top and back of most acoustic instruments. The braces on an acoustic instrument bare the brunt of string tension placed on the instrument and it is essential that they be securely glued in place. Because most acoustic flat tops are no more than say .100+/- of an inch, braces play a huge role in keeping everything together.

Deformities such as bulging, top rotation, ripples or cracks can develop when structural braces have broken loose and it some cases one may actually be able to hear a strange vibration when playing. A top which is no longer being strengthened by it's braces has a good chance of developing cracks or even severe top rotation (a 'twisting' of the top causing it to dip in front of the bridge and raise behind it). Repairing these properly can help save your instrument from noticeable damage in the future as well as more costly repairs. 

Brace Rattle - Loose braces are sometimes detected by the "clapping" like rattle they make when played or when the panel is tapped. Older instruments should be inspected regularly to insure everything is intact.

Here you see a typical scenario where the back brace has popped loose.
While braces are carved with a radius to render the top/back slightly arched this one has begun to curl excessively due to dryness. I have also seen braces that were too warped to glue back down.

Some brace repair can be tricky particularly if access is limited. Can I reach it? Ok...Can I get a clamp on it? It's quite rare that I can't actually, but some instruments will limit your access and require panel removal for access...again, that's not very common but it does happen. Guitars or mandolins with small soundholes or F-hole's are usually the one's that leave you scratching your head and thinking up new gadgets.

Before gluing the brace, any old crusty glue must first be removed to insure good adhesion. I personally go to great lengths to avoid leaving glue behind which makes these repairs obvious. (F-hole guitars...you are not included. ) But I prefer and strive for an invisible repair even though many give little thought to cosmetics with these types of repairs.

Split Braces

Split Braces -A broken brace like the one pictured above can be easily overlooked. While the brace remains securely glued in place, the fact that it is cracked can cause it to create a vibration and of course weaken it.

Loose & Missing Braces

Missing braces? Yes, I see that too. Braces that have come completely loose are far trickier to reglue than one that is still hanging on. Positioning is the most difficult part as you must place it, glue it and clamp it without it moving around. Some things are far easier to do when building than repairing, this is definitely one of them.
 

Bracing Patterns

Throughout the history of instrument making builders have strived to invent (and reinvent) the best bracing pattern possible... lending the top the strength it needs without making it too stiff or hampering vibrations. Though this is a avenue of great experimentation a few patterns and techniques are commonly seen in luthiery.