Filling a Low Nut Slot with Baking Soda and Superglue

Just to continue this mini-series on nut repair…

We’ve considered nuts where the slots had worn (or been cut) too low. This causes buzzing when the string is played in the open position. We’ve looked at fixing this problem but shimming under the nut — with a hardwood shim and with a rock-hard superglue-impregnated cardboard shim — to raise it up.

And, if you don’t want a new nut, or aren’t in a position to get one right now, these are both good alternatives.

But there’s another way.

Fill a low guitar or bass nut slot with baking soda and superglue

Baking soda and superglue nut repair


Baking soda.

And superglue.

The TL;DR description is that you fill the problem nut slot with baking soda and squidge in some superglue.

For a decent result, do the following:

Clean the slot with some sandpaper before you attempt a fill

First off clean out the slot. Use some folded over sandpaper (it doesn’t matter at this point if you widen or lower the slot because you’re fixing that later). You ideally want to clean out any gunk, lubricant, pencil graphite, etc. The sandpaper will also roughen the side of the slot slightly which will help at later stages. For this reason, go with around 220 or 320 grit paper.

Fine white powder used by musicians. Relax, it’s baking soda.

The first of the magic ingredients is baking soda. The bakers among you might be wondering if you can substitute baking powder. The answer is I’ve no idea but it’ll probably be just fine. I’ve read about the ‘baking soda and superglue’ trick for years but I don’t think it matters what you use. For instance, when I do this, I usually use bone dust I’ve collected from sanding other nuts and saddles. That works great, so I reckon that any fine, white powder substance you can find in the backstage area will likely do the trick.

Pack the offending slot well with baking soda.

Pack the offending nut slot with baking soda. And I do mean pack - press it in firmly. If I’m doing this, I’ll generally back fill completely and re-cut the slot. That’s probably not necessary if you just need to raise the slot a little to quickly stop a buzz. Fill up as much as you need with baking soda. Try to keep the front edge of your fill flush with the front edge of the nut.

Splodge out a little low-viscosity superglue onto a non-porus (and disposable) surface

Time for the second magic ingredient. Get some low-viscosity superglue (I’d strongly recommend not using the thicker stuff for this job) and squirt out a little onto something disposable and non-porous. As you can see, the inside of plastic/foil string packs works splendidly. In a little puddle like this, the superglue won’t dry for ages.

Use a toothpick to drop a little superglue where you want it

Use something like a toothpick (the end of a string folded over double works well too) to pick up a drop of superglue. Touch it to the baking powder and it should instantly wick into it. If you’re doing this while the nut is on your guitar, I’d recommend masking off around the nut and keeping a sheet of kitchen towel handy in case of any misplaced drips.

Wait a while for the superglue to cure and you can tidy up your repaired nut slot.

Now wait. Seriously. Wait a while. Give it a half hour if you can. Let it cure all through before you work on it or try string up. Personally, I don’t like to use accelerator on this — I prefer to let it cure and dry on its own without being shocked into curing from the outside in.

If you’ve got a deep or wide slot to fill, I recommend doing it in stages. Repeat the packing and glueing steps a few times. Doing so will help ensure good superglue penetration. Too deep and the glue can begin to harden before it wicks its way right to the bottom.

Two caveats on the backing soda and superglue nut fill repair

  1. I’d consider it temporary. I don’t do this repair often but when I do, I add a disclaimer. It can prevent having to replace an ‘original’ nut but it might not be permanent. It can certainly get you out of trouble when you discover your open string’s buzzing during soundcheck, but I’d advise following up with a more ‘certain’ repair when time allows.
  2. As with all of the shimming and filling nut repairs, ideally, the slots should be filed down and ‘set up’ properly afterwards. Otherwise you might be swapping slots that are too low for ones that are too high. It’s the lesser of two evils but it’s even better to get it sorted properly when you can.

Next time, I’ve a final nut fix for you. In the meantime, if you’re a touring musician or tech who decides to cross international borders with a small bag of baking powder, you should keep this email to help your defence.

Written by Gerry Haze and published at