How to Fix a Hairline Crack in a Guitar Neck – Easy Guide for Beginners

Author: Sam Poole | Updated: | This post may contain affiliate links.

Finding a crack on the neck of your guitar may make your stomach churn a tad. However, it’s not uncommon and can happen for a multitude of reasons. But no matter the reason, these cracks can usually be repaired with the proper adhesives and tools.

Understandably, with a hairline neck crack, you may be asking yourself how you’ll get the glue into the gap. And, indeed, traditional wood glue would not be appropriate for this specific problem. But there is an inexpensive and easy DIY solution, even if you’ve never done this kind of thing before.

Fixing a hairline crack in your guitar’s neck is easier than you think. With water, some CA super glue, and a couple of clamps, you’ll have that crack bonded perfectly in no time. And, after a wet sand and some buffing with a polish like the Meguiar’s Mirror Glaze, the neck will look and feel amazing.

Of course, you will need to follow a detailed, tried, and tested process. And one must be incredibly careful when working with a high viscosity CA superglue. Preparation is essential because the glue dries quickly. In fact, I recommend doing a ‘dress rehearsal’ or two before you carry out the actual repair.

Fixing the Hairline Crack in the Neck of Your Guitar

For the purposes of this guide, I’ll discuss repairing a crack on the main section of the neck. Let’s say that the opening runs behind the third and fourth frets. The following is a step-by-step guide to see you through the repair process hassle-free.

Prepare the Crack

Before starting, you must remove the strings from your guitar. The tension your strings place on the neck of the guitar will place unnecessary pressure on the crack. This pressure will make the repair job difficult for you. You also need to have the fretboard exposed for clamping.

Gently and gradually apply a small amount of pressure to open the crack up a little. If there’s any way you can clamp the neck to hold it in that position, that will help.

Take care not to place so much pressure on the area that you increase the size of the crack. But try to open the crack a little in a way that at least leaves you with one hand free.

You should also ensure that the crack is as dust-free as possible. The best way to do this is to blow on the cracked section when open before gluing.

Now you are ready for the gluing phase of the process.

Apply the CA Super Glue

Supplies You’ll Need

To apply the Starbond CA super glue (or similar) to the opening, you will need the following:

  • Spray bottle with water in it.
  • Paper Towels
  • Clean damp cloth
  • Gloves (Nitrile, something like these)
  • Wax paper (Larger than the area of the crack)
  • Guitar Neck Support Caul (like this one)
  • Irwin Quick-Grip One-Handed Bar Clamps (2 or more clamps)
  • Starbond EM-02 Premium Instant CA Super Glue with a micro-tip pipette

Practice Makes Perfect

Before opening your glue, practice the steps involved until you are sure of your methodology. Do a proper ‘dress rehearsal’ with a closed glue bottle and all the other elements.

Practicing is vital because the Starbond CA Super Glue dries lightning fast. To give you an idea, you will likely need to execute steps 2 to 5 below within about 5 seconds to be safe.

Pretend to execute the following steps and see how quickly you can do them:

  1. Apply the glue along the length of the crack. Make sure it flows into the gap as much as possible.
  2. Wipe off the excess glue with the damp cloth. Place the cloth aside with the glue side facing upward. You don’t want to glue your cloth to your workbench.
  3. Place the wax paper over the glued crack. This will prevent the glue from bonding to the caul and clamps when it seeps out after clamping.
  4. Place the guitar neck support caul, like this one, on top of wax paper.
  5. Clamp the caul down to hold the join in place. Place 2 or more Irwin quick-grip clamps on the neck depending on the length of the crack. You want one side of the clamp on top of the caul and the other on the fretboard. For this example, you’ll slot one clamp in at the third fret and the other in at the fourth. You want to close the crack as much as possible and hold it in place for the glue to dry.

Carry Out the Application

Once you’ve rehearsed a few times and are happy with your approach, you can get yourself ready to start. Remember to always wear gloves when working with any kind of glue, especially super glue. These nitrile disposable gloves are perfect for working with super glue.

You then need to prep the crack by spraying a bit of water on it. Don’t saturate the area. Just dampen the wood inside the gap a bit. Any CA super glue will work better when the wood is wet. The water also helps to shape the wood for a perfect join.

Wipe off excess water on the neck with your paper towel. But take care not to get bits of paper towel stuck in the crack while wiping the area.

As mentioned, Starbond CA super glue is highly viscous. So, you’ll want to have as small an opening as possible at the end of the micro-tip pipette applicator. Therefore, it’s best to open the point of the pipette with a pin rather than snip it with scissors. Using a pin will help you apply the glue with more precision and control.

Once you’ve applied the glue and clamped the area, as above, leave it for about 24 hours to dry. Letting it dry for this long will ensure that the bond is as secure as possible.

Remove Any Excess Glue

What You’ll Need

The next step is to remove excess glue from the surface of the neck. To do this, you will need:

  • About 4-inch-deep plastic container to hold water
  • Small bowl
  • Warm water
  • Dishwashing liquid
  • Standard rectangular eraser
  • 1500 grit sandpaper
  • 2000 grit sandpaper
  • Clean, dry cloth

Prepare Your Sandpaper

After 24 hours, you can loosen and take off your clamps, caul, and wax paper. You should see a tightly bonded line of glue where the crack was, with some excess adhesive on the surface. The excess glue will form a bump along the length of the section that was cracked.

Most guitars are finished with some form of lacquer. The CA super glue will leave a clear high gloss finish similar to the lacquer, bridging the existing finish on either side of the crack. I do not advise using any kind of solvent here, as this could severely damage the finish on your guitar.

The best thing to do is use 1500 and 2000 grit sandpaper to do a light wet sand of the area. You don’t want to remove any lacquer. You just want to gently remove the raised section of glue. Doing this will make the glue flush with the lacquer, so it looks good and feels smooth.

Half fill your plastic container with water. Then, place a 1-inch strip each of 1500 grit and 2000 grit sandpaper in the container of water. Leave the strips to soak in the water overnight.

Execute the Wet Sanding

The following day, place one drop of dishwashing liquid in your small bowl with warm water. Have your bowl of warm water, the container with wet sandpaper, eraser, and cloth at the ready.

Wipe down the treated section of the guitar’s neck with your dry cloth. Then take the 1500 grit strip of sandpaper out of the water. Wrap this strip around the short end of your standard rectangular eraser. In this instance, your eraser will act as a sanding block but much smaller.

Dip the sandpaper-covered end of the eraser in the warm soapy water. Then, lightly sand the excess glue off along where the line of the crack is. Do this in a circular motion, making tiny circles as you move along the crack line. Dip the sandpapered eraser into the soapy water every so often to maintain lubrication as you work.

Feel the surface with your fingers as you go to determine whether there is still excess glue on the surface. When there is a faint trace of adhesive residue left, move to the 2000 grit sandpaper.

Do a wet sand with the 2000 grit sandpaper as you did with the 1500 grit sandpaper. Continue to dip the sandpaper into the warm soapy water as you go. And remember to feel with your fingers often to determine whether it’s smooth enough.

When smooth to the touch, dry the area off well with your dry cloth. After that, you can move on to buffing this part of the neck to make it shine again.

Buffing the Repaired Area

What You’ll Need

The sanded section of the neck will look a bit dull to you at this point. But, not to worry. Next, you are going to work on the area with a compound to bring back its shine. To buff the repaired area, you will need the following supplies:

  • Meguiar’s M0316 Mirror Glaze Machine Glazing #3 (Light Cut: 1/10)
  • Chamois cloth
  • Clean, dry cloth
  • Dry buffing cloth
  • Gloves (Nitrile)

The Buffing Process

To give the neck a proper buff and bring that sheen back to the repaired area, you must use a premium compound. The best compound for this job, in my experience, is Meguiar’s M0316 Mirror Glaze Machine Glazing #3.

It’s best to avoid getting the compound on your skin. So, I advise that you wear your nitrile disposable gloves during the buffing process too.

To start, place some of the compound on your chamois cloth. Then, in a circular motion, gently rub up and down along the affected area. After 3 – 4 quick passes, immediately wipe the excess compound off with your dry cloth. Then grab your dry buffing cloth and give the repaired area a good rub.

Apply more Meguiar’s Mirror Glaze #3, as above, wipe off the excess, and rub with your buffing cloth again.

The finish may still be a bit dull after this second buff, but you should already see some difference. In fact, you may need to repeat this process 4 to 5 times to get a stunning gloss finish.

Once you’re happy with the shine and feel that the repaired area of the neck looks decent, you are done.

It’s time to re-string your guitar and get back to rocking out!

Take a Crack at It

While I’ve focused on a hypothetical crack in line with the third and fourth frets, cracks can occur anywhere. Even if the damage is on the headstock or base of the neck, you can still use the above approach.

You may just have to adapt how you support and clamp the glued section. However, this will all depend on the shape of the affected area.

Granted, repairing the crack on the neck of your guitar may seem like a complex process at first glance. But if you tackle the repair process patiently, one step at a time, you’ll be fine.

About Sam Poole

Sam is an experienced writer and a keen musician. She loves listening to everything from The Beatles to Tool, although the former is her favorite band. Sam started with the piano, and has also played guitar extensively. More recently she's picked up the bass guitar, and is currently exploring the instrument in her free time.

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