fix a broken brace

Once you’ve determined that a brace is indeed loose, take your guitar to an experienced luthier, who will be able to determine why it’s loose and perhaps find other loose braces or related problems that should be fixed at the same time. Here are some of the things pros will consider before regluing a loose brace, and a few steps they’re likely to take to fix the problem.

Two important considerations are to determine what type of glue was used to install the braces so the right glue is used for the repair, and to clean out the old glue and dirt from the loose area. The majority of quality factory-made guitars built before the early 1960s were built with hot hide glue. Since then, the white or yellow aliphatic-resin glues have been more common, but with inexpensive imported guitars there’s no telling what glue may have been used (something that dries fast, for sure, and epoxy or Super Glue may not be out of the question).

Hide glue (see Acoustic Guitar, March 2009) has a dark, amber, crystalline look like dried molasses; it softens—rejuvenates, even—with water and heat, and because of this, hide glue residue left between a brace and the top or back presents no problem during regluing, because it will join with any new hide glue (other glues won’t because they don’t dissolve into the original glue).

The “white” glues have a white or grey translucent look, much like clear silicone caulk, and though they may soften to some extent with heat and moisture, they don’t rejuvenate—which makes it important to remove all of the old glue from any gap, because clumps of glue residue will keep a gap from closing entirely.

A professional will also consider the order in which to do any gluing so that an open crack or adjoining problem isn’t inadvertently glued during the process and rendered hard to fix because of it. I practice all but the simplest glue-ups “dry” (without glue) to make sure that any clamps, fixtures, and clamping cauls work the way I envision, and that I can execute the work fast enough (this is most important with hide glue, since it will set in about two minutes).

Dry runs also show me whether or not I can reach the work area with enough strength, flexibility, and accuracy, not only to glue a loose brace properly but to clean up any glue squeeze-out or mess afterward. (Reach is important—an experienced tech will know not to attempt a job if he or she can’t reach it, and will either pass the work to someone with smaller arms or design a fixture just for the job at hand—that’s how some of our greatest repair tools are developed.)

This is a serious consideration because we all see too many repairs where a novice obviously wasn’t able to reach a brace, or didn’t have the right tool, and instead just smeared glue “at” the area, hoping that something good might come from it. Not knowing how to get glue where it’s needed, lacking the proper tools, or having big arms are not a valid excuses for poor brace gluing.

Clamping tools and techniques may be as simple as using long “brace,” or “soundhole” clamps, which are C-clamps made just for the work, or using sticks and props whittled on the spot to hold a brace in place. On the other hand, your luthier may spend days just conjuring up a new tool or technique.

For several of us at Stewart-MacDonald Manufacturing, where I work, our gig is designing and producing specialized tools for all repair and building situations. A new tool for brace gluing that we’re quite proud of is the Scissor Jack, which can be placed through the soundhole to reach a loose brace and gently clamp it shut. This tool has raised the bar for interior acoustic repairs, and hopefully your tech will have at least one of these tools.

Ready to Go

Most cases of loose braces are easily fixed by an experienced repair person, and they’re no cause for serious alarm. However, knowing what to look for can help you diagnose problems with your guitars and will inform any conversation you have with your repair person.