Best fret slot filler for phenoboard fretless

[greiswig]

Hi, all,

I recently bought a Zon "fretless," which turned out to be a converted instrument. I found this out when I realized that it wasn't setup issues causing the odd spots where the strings would "zing" rather than shifting smoothly across pitches.

I refinished the fingerboard myself, using cyanoacrylate. It worked very well, and I was able to get a mirror-smooth finish. However, in the two weeks since I did that, the material that the guy whoever did the conversion used to fill in the fret slots has retreated...shrunk down slightly below the level of the rest of the fretboard, taking with it the cyanoacrylate.

I would guess that he used wood putty or something prone to shrinking from humidity changes.

I'm guessing that, if I want this neck perfect, I need to saw out the fret slots, then refill them. What I'd like to know is what would make for a better filler to use with phenowood? I'm tempted to used JB weld or something, because it would be impervious to humidity change, and a nice light gray color. But it also seems extreme! It's steel-filled epoxy. What would work better?

[202dy]

The best material to use is the same material as the fret board. Failing that, every other filler is going to have pros and cons. JB Weld would work, binding material would work, steel inserts will also work. Every one of them has a different coefficient of expansion and is going to react differently to different adhesives. The important thing is if solid material is used to make sure that it is sized precisely to the slot size or the neck could be wedged into a back bow. With a liquid or paste filler, almost everyone is going to be more flexible than the phenolic, so too much front bow is the danger. Another choice would be to sand the new finish off. Sand the fingerboard and push the dust into the slots, packing it relatively tight, about one third of the slot height. Wick some liquid thin super glue and let it set up. Lather, rinse, and repeat.

If you call or email Joe Zon he will give you advice on this. He is generally very helpful and loves to talk about his basses. He is proud of his instruments and rightly so.

[greiswig]

Thanks muchly for the reply. I guess I'm surprised that the stiffness of this material is much of an issue here, given that the rest of the neck is composite. There certainly doesn't seem to be an issue with bowing of the neck, even without a truss rod. It has pretty much perfect relief.

What is the cause of this kind of "retreat" from the surface by a filler? Is it that it is actually shrinking, but only away from the surface and not along the axis of the fingerboard? Or is the theory that it gets pinched in the slot, and that somehow forces it down in? And why would it appear over time, and not immediately when strung up? It played like a dream for a couple of weeks...

[202dy]

Good question. Only guesses instead of a good answer. We don't know what material they chose to fill the slots. If it was a slurry of something in a solvent it could be a function of the solvent gassing off over time? This is why it may be better to use a solid filler instead of a putty style filler it the solid filler is of similar density to the fingerboard. I don't know.

Anyone else have an idea?

[Eric Perry]

If I may hijack for one second.. Is there a way to dye or color the cyanoacrylate prior to application? I have an old Korean Spector that I defretted, and I'd love to give it a mirror black fingerboard finish.

Thoughts?


Again, sorry for the hijack.