Vintage National Resophonic Refret
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This National style 0 was built in 1932 and has a badly bowed neck.
The dyed maple or fruitwood fretboard has shrunken, cracked and become brittle. The ebonized fretboard has the structural integrity of charred firewood. There is little height left on the original frets and they are worn beneath the plain steel strings.
Protruding fret ends, also called “fret-sprout” is a sign of a dried out neck. This one has shrunken permanently. Notice the binding was partially filed away along the side of the neck, exposing the subsurface portion of the fret called the “tang“.
Removing the neck from the body will make refretting this vintage neck go a little faster and easier. The “neck stick” is mortised into the neck and is secured to the body with a series of screws and wedges. When the refret is complete, I’ll reset the neck to a better angle in order to lower the action.
Gluing the fret slots with thin super glue will harden the end grain of this brittle fretboard within the fret slots. A generous bead of glue will also help fill and solidify the many cracks in the fretboard.
Removing the excess glue with a small piece of paper towel dampened with acetone.
Removing the frets from a vintage, ebonized fretboard is tricky business. If I’m not careful, the little barbs on the fret tang will badly chip the brittle fretboard as the frets are extracted. My modified end-nippers very slowly begin to lift the fret as I push the tool down against the fretboard and close the jaws. A modified soldering gun heats the fret which reduces chipping.
Two razor blades with their beveled cutting edges ground completely away are jammed beneath the fret crown. The razor blades shim-up the fret pullers so they can lift the fret clear of the fretboard while the razor blades press down against the brittle fretboard beneath the fret further reducing the likely hood of chipping.
A clean fret extraction. They won’t all come out of this neck as clean as this fret did.
Chips in the fretboard are unavoidable when refretting a deteriorated dyed fruitwood or maple fretboard like this one. I’ll wick some super glue under the chip then press it down with the tip of a screw driver.
Clamping the chip down with a caul lined with waxed paper for a couple of minutes ensures a clean repair of the chip. I’ll remove the remaining frets and repair any chipping in the fretboard as I go.
More super glue applied to the fretboard surrounding each fret slot will strengthen any microscopic chips in the fretboard caused by the little barbs on the fret tangs. I’ll wipe off the excess glue before it hardens.
Sanding the fretboard with 220 grit sandpaper wrapped around a belt-sander cleaning-eraser won’t change the original flat(ish) radius of the fretboard but it will resurface the fretboard and remove any remaining glue residue. I’ll follow up with 600 grit sandpaper.
Preparing the fret slots. I’ve beveled the tops of the fret slots, now I’m resawing the Fret Slots which gets rid of any obstructions within the slot that could prevent the new frets from seating and ensures that none of the slots are too narrow to accept the new fretwire.
I created a few more chips in the fretboard while preparing the fret slots. Again, par for the course when working with a brittle, dyed-fruitwood fretboard. These chips are missing and will need to be filled.
Filling the chips with a mixture of medium super glue and ebony dust is pretty quick. A teflon “dam” keeps the glue out of the fret slot. I won’t use accelerator on the super glue because it might discolor the filler.
Trimming the filler with a sharp chisel. I’ll leave the filler a little proud of the fretboard.
Scraping the filler flush to the fretboard is quick and clean with a razor blade. I’ve given the razor blade a burr so it acts as a scraper. Two pieces of tape prevent the razor blade from scraping the surrounding fretboard. This is a technique that I learned from Frank Ford’s great guitar repair site, frets.com.
Sanding the Filler Flush with 1000 grit sandpaper. Moderate downward pressure from my stationary thumb sands the filled area of the fretboard as I pull the sandpaper with my other hand. This is a tip that Dan Erlewine advocates for finish touchup work. I’ll go back and spot sand this area with 600 grit sandpaper to give it the same sheen as the rest of the fretboard.
The filler looks pretty good. Most of it will be covered by the new frets.
A compression refret will help straighten the neck. I’m pressing medium sized nickel silver fretwire with a slightly wider tang width into the slots. This compresses the the neck thus making it less bowed, or less concave.
Trimming the tang width of the upper frets with the stew mac fret barber will allow the frets to more easily seat in the upper fret slots. Only the first 9 or so fret slots can be effectively compressed. The remaining frets should be installed as usual with a not-too-tight fit.
Gluing and clamping the frets with the universal fret pressing insert allows the frets to properly seat against the uneven fretboard radius and stay that way. I glue as usual with a thin bead of super glue, a quick clean up with a paper towel dampened with acetone and a drop of accelerator applied while the fret is clamped. Next I’ll bevel the fret ends to the same severe angle as the original frets thus preserving the already thin and partially missing binding.
Leveling the frets. I’m not going to simulate string tension for this refret. Instead I’m spot sanding the trouble spot in the neck over the heal with 400 grit PSA sandpaper on a short, flat sanding beam and lightly kissing the tops of the remaining frets.
High spots in the neck/fretboard translate to the frets. I’ll have to recrown these frets over the heel so the peak of the crown is narrow for optimal playability and intonation.
A Crowning File recrowns the flat frets at the heel and rounds the fret ends.
Fret erasers are a good way to remove the crowning file marks from the four or so frets that I had to recrown.
Sanding the frets and fretboard with 600 grit and 1000 grit sandpaper wrapped around a thick piece of card stock gets rid of the sanding marks on the frets. Next I’ll tape off the fretboard for buffing. I don’t want to buff the fretboard because it will look too shiny on this old guitar.
Buffing the Frets with the buffing wheels gets them nice and shinny without making the fretboard appear overly polished.
Removing the Tape with a heat gun prevents the tape from chipping the fretboard. Next I’ll apply a thin coat of black fretboard dye. It won’t hurt the fretboard and it will give the wood an even color and dull sheen.
New frets have enough height for comfortable playing and they have compressed the neck straight. Next, I’ll reset the neck angle, attach the neck and set up the guitar.