In some cases the neck might not be warped, but the frets of your guitar may have become somehow misaligned. If this is your case, you should notice one or more frets higher or lower than other surrounding frets. Sometimes frets become misaligned because of warping in the neck of your guitar. When you notice misaligned frets, inspect the area carefully. The upper frets of your guitar should be almost perfectly straight, if not perfectly straight. Deviations in the top frets are a good indication that you have a warping problem. Don’t look to the wood of the neck and fretboard or its edge to determine warp. This part of your guitar can become worn down over time from playing, and can make the neck appeared warped even when it is not. [2] X Research source
Sometimes warping is harder to notice from one end of your guitar than the other. By performing a visual check of the neck of your instrument from both the body and the headstock, you’ll stand the best chance of noticing warping. You may want to mark any unnatural variances in the neck you see with a piece of tape. Especially for necks that have severely irregular warping, jotting down or marking where you notice the distortions in the wood will help you make more precise adjustments later.
Press the sixth string of your guitar at the first and twelfth (or first and fourteenth for electric/steel guitars). There should only be a tiny gap, about 1/64th of an inch (. 4 mm), between your string and fretboard on the sixth fret. No gap is an indication of unnatural back-tilt, which can be fixed by adjusting the truss rod. Press the sixth string at the eighth and highest frets. The string should lie flat along the board along the midpoint (approximately the twelfth to fourteenth frets). A gap here indicates a rising warp in the neck of your guitar. Press your sixth string along the first and last frets. If there is a small gap between the string sixth fret the warp in the neck is centralized in the upper part of the neck away from the body. This can usually be fixed by adjusting the truss rod. If your string and sixth fret form a gap larger than 1/64th of an inch (. 4 mm), the neck is warped. Hold the sixth string at the first fret and slowly slide down the fretboard with your other hand. As you slide down the frets, if the gap at your sixth fret decreases, the neck is warped and will need to be straightened. [3] X Research source [4] X Research source
To check your frets, take a straight metal ruler and lie it along the fretboard. A misaligned fret may only be out of alignment by a few thousandths of an inch. This might not be observable with your eyes, but if you lay the metal along the frets, the misaligned fret will cause the ruler to seesaw slightly back and forth. [5] X Research source
You may want to hold the neck of your guitar into place with a rubber ended clamp or some other suitable clamp for woodwork. This is not necessary, but can make removing the frets easier. Make sure your iron has plenty of water. You’ll need lots of steam to loosen the glue fastening your frets and guitar neck. You may want to bring some extra water in a pitcher in case you run dry mid-steaming. It is possible that damage could occur to your guitar during this process. If you have an expensive guitar, you may be better off having a professional repair the neck of your instrument. [6] X Research source
Depending on your guitar, you may need to apply more or less steam to the neck to loosen the glue. Test the bond between fret and neck every minute or so be probing it with your scraper. The fretboard and neck will become very hot from the heat of your iron. Be careful when touching the neck or handling your guitar. To prevent being burned or scalded, you may want to wear a pair of gloves or wrap the neck of your guitar in a towel after removing your iron. When the glue has sufficiently loosened, you should be able to get an inch or two of your scraper (or putty knife) inserted between your fret and neck. This should be enough to hold your scraper in place between the two parts unassisted. [7] X Research source
Keep your scraper at a right angle (forming an L-shape with) the neck of your guitar. This way you’ll be able to tap the protruding end and the handle to wedge the fretboard free evenly. This will help prevent damage to the neck due to unequal stress being applied by your scraper. Removing frets from the neck of your guitar can be a long an involved process. You should work slowly to prevent the wood from cracking and splintering. Damage to the neck can permanently ruin it. [8] X Research source [9] X Research source
Even when the fretboard begins coming free more easily, work slowly and methodically. Working too fast can cause damage to the neck or fretboard of your guitar. Once the glue has become loosened, try to wiggle your scraper back and forth in the direction of the still-glued segments. You may find this loosens the glue more easily. [10] X Research source [11] X Research source
Use your tape measure to find the distance between the area of the neck that is warped and the surface you are working on when the body of your guitar is laying flat. This will be the height of your cradle block. The length of the block should be about five inches (12. 7 cm), and its width an inch (2. 54 cm) wider than the neck of your guitar on both sides. [12] X Research source
Your trough doesn’t need to be too deep; a ¼ inch (6. 35 mm) deep should be sufficient to hold your guitar in place. This will also help prevent stress fractures in the wood of the neck. [13] X Research source
The midpoint mark is where the headstock of your guitar will overhang. The marks to either side of the midpoint will be where you add tension rods, which you will use to straighten the warp of your guitar. [14] X Research source
Be careful you don’t damage what is below your 2 by 4 when you pound the nails through the board. You’ll want your nail to extend 2 to 3 inches (5 to 7. 6 cm) out the opposite side of your 2 by 4. [15] X Research source
You may want to put small pieces of rubber between your clamp and guitar, guitar and work area, and clamp and work area. These small pieces of rubber will prevent damage to your guitar or work area. At this point, your guitar should be clamped at the base to your work area, the warped part of the neck should be nested in your cradle, and your tension block should be clamped to the work area with the headstock of your guitar overhanging its midpoint.
Place your last two rubber guards in between the string and the headstock so the string does not damage the wood, and then wind the strings tightly around the tension rods. Your low E string should work nicely for warp repair purposes. Thicker guitar strings will allow you to apply more tension to the neck to correct the warp. [16] X Research source [17] X Research source
Using the straightedges, you’ll be more able to see if the warp has been corrected. If the top of each straightedge is aligned and level, your warp has been corrected. You can also lay your straightedge longways down the neck of your guitar. This may make it easier for your to see lengthwise warping. You may have to make several small adjustments before your warp is corrected. Be careful not to apply too much tension to the neck of your guitar; this could result in the neck cracking. Once the neck is straight, you should add a half turn to each tuning peg to give the slightest backward bowing in the neck of your guitar. [18] X Research source
A constant temperature of about 350 to 400 degrees Fahrenheit (176 to 204 degrees Celsius) applied to your guitar neck for about two to three hours should help the neck hold its repaired shape. Afterward, you should allow the wood to cool for about a day. [19] X Research source [20] X Research source [21] X Research source
