Remember, last time, when I talked about shimming a nut with hardwood? Remember how I mentioned that sometimes you might see a nut shimmed with a piece of cardboard and I advised against that?
Well, there’s an exception.
Thanks to Richard for emailing to remind me of this exception. I knew about it but have never actually done it so it’s good to get a ‘this works’ recommendation. I tried it and, can confirm that it’s a good way to go.
For all intents and purposes, the process is the same as last time. Instead of a piece of wood, we glue a piece of cardboard to the bottom of the nut.
“Oh, but cardboard’s soft. What about my tone?” you yell.
“Ahhh. Calm down about your precious tone. There’s a trick,” I say.
I’ll get to it in a minute. First let’s recap the procedure…
How to shim a nut with cardboard
First off, you don’t want any shiny surfaces for your glueing operation. Use some sandpaper (around 220 or 320 grit or so) to lightly scuff the bottom of the nut. Then, if your cardboard shim has a glossy/satin coating, very lightly scuff that with the sandpaper. Just go in one direction to avoid wrinkling or creasing the cardboard (like some idiot did before taking this photo). Remember that this is a very light sanding just to remove the glossy film. A couple of gently rubs will do the trick.
Then, apply a uniform layer of superglue to the bottom of your nut. Doesn’t need to be too thick but a little squeeze-out later isn’t the end of the world.
Place the nut on your cardboard (on a flat surface) and apply pressure. Wait for it to cure off. The glue drying to the cardboard will be pretty fast but any blobby squeeze-out might be a little slower (some accelerator is handy if you have it — otherwise wait a couple of minutes).
Use an exacto knife to trim the cardboard close to the edges. Don’t worry about getting in tight to the nut edge. We’ll sort that out later. Just don't tear out chunks inside the nut's perimeter.
Now the trick.
The low-viscosity, water-thin stuff is best for this job. What you want to do is to soak the bottom of the cardboard with superglue. Hold the nut with a pliers or tweezers as you do this. The low-viscosity glue can run and dribble easily, and it sticks to fingers amazingly quickly. Ideally, though, you’ll be careful and not have any drips. Keep watching as you go and use a piece of paper towel if you see a drip.
Sorry for the out-of-focus thing on that image — not always easy to do this stuff one-handed.
The idea is to completely impregnate the cardboard with superglue (which is why the thin stuff is better). Once you think it’s soaked in, wait for it to dry completely.
When dry, use some sandpaper on a flat surface to sand back the protruding cardboard/glue until it’s flush with the sides of the nut. You can use the sandpaper to even up the bottom of the glue-hardened cardboard too
The result is usually relatively discreet. And, because the cardboard is now completely soaked in superglue, it’s become super hard and it’s not going to have a major impact on your tone.
There it is. Glue-hardened cardboard shims. Cool.
Personally, I prefer the idea of a hunk of wood but this is, absolutely, a sound fix and will work perfectly well. It’ll certainly get you out of a hole if you find yourself with a low nut.
Written by Gerry Haze and published at hazeguitars.com