Remove the Nut
Now the first thing you’ll need to do before you shim up a nut is to remove the nut. In order to do this, you’ll need a soldering iron and a wet paper towel or rag (a cotton rag or cloth would be best – avoid highly flammable and/or synthetic materials).
1. Remove all of the strings from your guitar or loosen them enough to pull them over to the side of your nut, so that you can remove it.
2. Heat up your soldering iron and wet your cloth or paper towel.
3. Once your soldering is hot, place the damp cloth on your nut, being sure that the damp part of the cloth covers the crack where the nut makes contact with your fingerboard.
4. Now use the soldering iron to shoot steam into the the space between the nut and the fingerboard. Move the soldering iron from side to side, from one end of the nut to the other. (The steam will loosen any glue on the face of the nut.)
5. Use a block of wood or plastic block, and a mallet, to tap (or pry) the nut out and remove it.
How to Make a Shim
Now that the nut is out, it’s time to shim it up. First, use a razor blade to cut out a small shim of self adhering acetate or wood. (Some players are purists and reject this step on principal. Others don’t mind. If you can’t bare the thought of placing a shim under your nut, then you’ll need to replace it.)
1. Cut the shim out and attach it to the nut. If you’re using an adhesive back as your shim material then this is very simple process. You just remove the backing from the acetate and and stick it to your nut. If you’re using wood, you’ll need to glue it in place and let it set overnight.
2. Use a razor blade to make your shim flush with the sides of the nut.
Replace the Nut
1. Place a very small dab of glue on the face of your nut (center) and spread it across the surface with your finger.
2. Carefully put the nut back into place and and wipe away any excess glue that overflowed onto the fret board with a damp cloth.
3. Restring your guitar.
4. Assess the height of your strings with a feeler gauge.
5. Hopefully, if things worked out right, your strings are either just right or a little too high. If some strings are still sitting too low then your shim wasn’t thick enough and you’ll need to remove the strings again and raise the nut a little higher (better a little too high than too low this time; you don’t want to have to keep removing the nut and shimming it up).
- If your strings are sitting at the right height, then you’re done with this step and can continue your setup.
- If some strings are too high now, then you’ll want to file down your nut slots to get them to the right height.