Low nut slot repair question

This was a weird one. I spent a great deal of time shaping, fitting, filing and polishing a new nut yesterday and thought it turned out great. The high e slot gave me fits however as my .010 file kept binding up on me and when placing the string back in the slot to test it was as if I cut the slot with a .008 file. I finally got it to where I liked it, set up the guitar and thought I was done. A few hours later I inspected it again and found zero clearance on the first fret when holding the string down lightly to the top of the 3rd fret. I think my Stew Mac .010 file must be wearing out and not allowing a clean cut.

Make yourself a little puffer bottle for the accelerator (I like Zip Kicker).  The way this stuff works--it's the vapor that "kicks" the CA into a solid inert polymer.

Get yourself a small dropper bottle (Amazon, etc.).  I like the type with the small steel needle because these include a silicone rubber cap that perfectly seals the needle tip.  Screw-on and snap caps don't seal as well and the Kicker will evaporate over time.

Here's how:

Cut a strip of paper towel or cotton cloth about 1.5" wide and 3" long.  Roll it up tightly and press it into the bottle.  Shake the bottle to loosen the roll inside, and then add a very small amount of Kicker.  The goal is to saturate the paper/cloth without having any visible liquid pooling in the bottle.  This prevents squirting liquid Kicker onto wet CA and causing it to foam up, turn cloudy, and harden into a rough surface.



Okay, back to the nut slot.  I always clean out the slot with the folded edge of a piece of paper to remove any lube/nut sauce/etc., and then give the slot a few passes with a file one gauge up to ensure I'm starting with perfectly clean material for a good CA bond.

Next I cut two very small strips of Scotch tape (about 3mm x 5mm) and stick them on the front and back of the nut, covering the ends of the slot.  These serve as little dams to keep the dust in the slot and keep the CA contained. 

I use the tip of an Xacto blade to drop in a little pinch of dust, and then follow that with a small drop of water-thin CA from the tip of the Xacto blade or from a toothpick.  Applying the CA directly from the bottle is fraught with danger.
  
Give it about 10 seconds to set up, and then gently puff on the area with the Kicker puffer.  A series of small gentle pinches of the bottle will do it.  If you work under a bright light with magnification, watch the reflection of the light in the shiny surface of the wet CA and you'll see it when it freezes up.  NOTE: the surface of CA freezes before the underlying portion.  I don't care how adamant a CA maker's claims of "instant set" are, but I trust the clock more than I trust ad copy. 

Once the surface freezes, it's safe to apply a teensy drop of Kicker (from a toothpick or the tip of the Xacto) to the CA and it will be ok.

Give the repair about 10 minutes to rest, and then peel off the little tape dams and file/sand the nut to shape and re-slot it.

Pro tip: place a drop of thin or medium CA onto a non-absorbent surface and practice with the Kicker in the puff bottle.  You don't want to blow the drop across the surface, so rapid gentle puffs from about an inch away will do the trick.  Watch the reflection of your overhead light in the wet surface of the CA.  You'll get the hang of it in a single session.

Fantastic stuff, thank you gents. Peegoo I remember the puffer bottle idea from one of your previous posts and was hoping you'd chime in.

The weird thing about my particular issue is that while the slot is clearly lower than it should be I'm not getting any abnormalities, fret buzz, open string rattle, etc. Its almost like the string just "feels" too low and awkward to bend (this git has vintage frets).

The nut action is probably is too low. There's a balance between low action and ease of play; really low strings with low frets are harder to bend because you're relying on friction between the fingertip and the string to push the string along the fret for the bend.  Generally, somewhere between .018" and .020" between each string and the first fret is pretty good.

Higher action (and I'm talking only a few thou' of additional height here) as well as taller frets allow you to get the finger behind the string and push it along the fret.  In your case, the combination of super low action and vintage frets is conspiring against you.

A similar question came up in another forum; the question was, "how do I mute the B string while bending the high E string?" I posted this.  You have to get the fingertip behind the B string to push it out of the way, off of the fret.  Low action and vintage frets make this move quite a bit more difficult.

Did the low and high e strings following Peegoo's method and had mixed results. The high e worked perfect, the low e chunked out. I think there were 2 factors. I don't think I effectively cleaned the low e slot out good enough and I didn't seem to get good (any?) results with the puffer. Its probably the big box store brand kicker I used.

I redid both and carefully applied the kicker instead of using the puffer method. Let it sit overnight and recut this morning with good results. I had more slop than I cared for which took an extra few minutes to sand and polish (just finishing off with 600/1500/2500 grit). Time will tell.

Thank you guys, your shared skills make this place invaluable.

Bleached/unbleached is a color thing. On an older guitar that has battle scars and the wood has darkened, unbleached tends to blend in with the 'surroundings' better. A stark white nut looks out of place.

Bone is the most inconsistent of nut materials; it can be hard, it can be soft. I always do the Drop Test to find the nut blank that rings the most. When dropped onto a hard surface from about 6", softer bone makes a 'thud' sound. Harder bone rings like a piece of glass.

I think bleaching removes the softer material were as an unbleached nut retains its integrity and is less porous. This is my thinking... Woody

I read up on this a few years back after talking to a piano builder who told me it'd be possible to make some money making bone veneer for the keys. Evidently there are only one or two people that make them and they are overseas if I remember right. Anyway, the process is simple, if annoying. The bones themselves are first boiled to remove any unwanted material, then milled. After milling the pieces are submerged in naphtha which leaches the fat and oils from the bone. I think it takes a while and may involve putting the pieces in fresh solvent along the way. So you'd have to have an appropriately safe set-up and also have to dispose of the spent solvent.

It's hard to imagine that bleaching would change the structure of the bone much, but I don't know enough. If you only used bleach you'd end up with fatty, oily bone which would be bad for use on guitars. Do the unbleached blanks we buy still have enough oils in them to account for the aforementioned lubricating qualities, hardness differences, etc.? Again, I don't know enough but I'm dubious. I've always assumed that any differences in hardness, texture, etc. have to do with the bone (and animal) in question.

I'll tell you about a nut slot fix that doesn't work. I thought I had a bright idea and bought a $10 kit of optically clear, UV cured resin ("Bluefixx"). Cleaned the slot of any lube (with Naptha) and applied the goop. Hit it with the UV light. Seemed pretty hard and commenced to filing. The thin layer slid out of the slot. Apparently the goop doesn't have much shear strength. Maybe good for other things but not this.