Sometimes, the use of cleats is a necessity to ensure longevity for a crack. Here, the square-shaped cleats on this vintage Martin are cut from Brazilian rosewood to match the guitar’s wood, and are placed across the grain to “stitch” the compromised area.

In my last column [“Just Say No To Cracks,” June 2018], we talked about cracks and why they happen. We also took a close look at what to consider during a crack repair and at the continued care of the instrument to ensure it doesn’t happen again. We now need to ponder interior support, backers, or cleats, which may be the third leg of the trifecta to better predict the outcome of a repair’s longevity and the effect it could have on an instrument’s tone.

How to deem a repair complete is debatable. For example, some may say a repair is not complete until the finish has some degree of touch-up performed. Closer to the truth is that once a crack is repaired to the level it’s stable—and is going to stay that way—it’s complete. Anything else is in support of that. So, the question is if it’s going to stay that way.

When a crack stays open for too long, it can develop a “memory,” so to speak. This is what I like to call “gaposis.” In such an instance, the repair may require a little extra help to stabilize the damage, and the repairperson may opt to use cleats or backers, especially if the damage seems questionable enough that the wood won’t remain stable over the long haul.

A cleat is a small, thin piece of wood that’s commonly made of the same wood as what’s being repaired. The grain of the cleat runs opposite of the area being glued, which helps “stitch” the compromised area back together. Fellow builder Sam Guidry and I have had many conversations about the effect cleats and backers can have on the overall tone of an instrument. Tone is king in the end, so any step in the process that doesn’t increase stability and also decreases tone is certainly not a good choice.

In our repair shop, we often remove unnecessary cleats from older instruments. Any extra mass from the cleats can hurt tone, especially if the cleats are on the top. If the crack being repaired can fit back together tightly—often the case with a lack-of-humidity crack—the glue joint will be strong enough to hold the repair together on its own, and will also add a level of external sealant against humidity, oils, polishes, and such. In fact, cleating a crack like this can lead to other cracks. How can this be?

A cleated humidity crack will not stay closed any better than a well-glued, properly re-humidified crack repair.

We must understand that lack-of-humidity cracks occur when a guitar’s wood dries out and shrinks. Once the crack is repaired, it should stay closed if the instrument is properly humidified. A cleated humidity crack will not stay closed any better than a well-glued, properly re-humidified crack repair. And since a cleated crack will often cause a split next to the cleat if the guitar dries out once again, you could end up with a repaired crack, a cleat, and a new crack beside the cleat. We prefer to simply re-glue such cracks, educate customers, and send them on their way with a new humidifier.

As repair people, we want ideal situations where what we are fixing fits together perfectly and to know the glue-up will be easy. As we all know, however, life just isn’t that easy. Anytime we think a glue joint won’t be enough to hold, then “to cleat, or not to cleat” is the question. We will often advise our customers that they not cleat and wait to see how it goes if stability seems at all probable. With a general, everyday crack repair, it is very seldom that I choose to cleat the crack. But then again, on some older vintage instruments, the cracks have likely been open for decades and the repair will not be a sound one without some assistance. Yes, we are very sensitive about adding material to an instrument and generally choose the conservative approach so to not compromise the instrument, but sometimes there is no other option.

While a cleat is typically a small piece of wood (generally the size of a dime and in the shapes of squares, diamonds, or circles), backers are thin, longer cross-grained supports for strengthening larger areas. Don’t get me wrong: Either of these options, if performed professionally, can be the correct choice. Cleats and backers can help repair and stabilize what seems to be irreparable damage to an instrument. It’s just that the general need for cleats or backers has been widely exaggerated. Not only have we often removed unneeded cleats and backers from instruments, we’ve also removed them because they were installed poorly. That’s because installing a cleat or backer is a tough job to perform correctly and cleanly. Even the excess glue that can come with a poorly installed cleat or backer is an issue.

I have owned some of the most desirable world-class acoustic guitars—both vintage and otherwise. As a player and repairperson, I have restored these instruments (including the removal of many unnecessary internal repairs) to bring tone back to life. And these instruments have held up fine, cracks and all. This is not always the case, so, again, make sure you talk all options through with your repairperson to confirm you are making the correct choice for your instrument.