I was watching a Stew Mac video the other day, and the fellow that was demonstrating---not Dan Earlywine---said to run some thin CA along the edges of the frets for "better tone quality".
I make classicals, and am wondering if this might apply to my builds. I'm quite fussy about getting the fret slots right at .023", and use Jescar fret wire---no problems with frets coming loose.
My first thought is that the CA would help in doing a fret job, with slots a bit too wide, but I thought that I would ask.
That's a good question!
Unlike most classical builders I make a conical section radiused fingerboard---18 inches at the nut, and 28 inches at the 19th fret. That's not much of a radius by steel string standards, but I slot my boards before routing the radius, so the slots leave a gap below the fret in the center of the board.
Where can I get a research grant to test this out?
By the way, players seem to like the radiused board as it makes barring easier. Often the player doesn't notice the radius until I point it out!
While we have a default/standard fret size for everyday work the customer ultimately has the final say in choosing fret sizes and radiuses. Along with that choice comes a variation in fret tang depth and width. We also do a number of radius checks and trues in the process of bringing a fingerboard to completion. All this happens after initial slotting on our machine saw gig which has mechanical limitations. Consequently we cut flat fret slot bottoms with a prudent tolerance gap.
We use unbound fingerboards to enhance performance and stability and initially inject thin CA in from both sides of the board and once that has cured we then finish the job by wicking in medium CA to seal the deal and tidy the ends. This medium shot also has the added bonus of filleting out finishing marks in the fret end area and adding security to this critical part of the fret. This final shot of medium CA pads out the fret bottom and fills the gap to some extent and we live with that. Also, for attribution purposes; I pinched this process from PRS who show it on their Youtube Vids if our readers are interested.
I would like to have a conformal fret slot bottom but the reality of making in numbers is that even that form would need a tolerance gap. I think the extra material removed in a flat bottom slot is significant but as we have good tolerances we can compression fret to a small degree and the CA applications into the slot fills this area a bit, stiffens up the board and adds consistency anyway.
i've worked on plenty of very expensive guitars with fret ends that have sprung up over not even that long a time. it's not awesome when i'm cleaning up the board on a 10-year old $4000 boutique acoustic and i get nice little tufts of steel wool stuck up under the fret ends all the way down the board :( a proper CA fret installation would have prevented this situation.
CA is great for frets because it fills gaps, doesn't introduce water to the slot to swell the wood and throw off your leveling afterwards, seals the slot from any further moisture, and dries "brittle" for nice tone transfer.
you obviously don't want to use glue as a substitute for a proper tight slot fit, but in addition to such it's the ticket for reliability.
over on TGP famed luthier terry mcinturff turned us on to the type of CA he uses for his builds; it's called loctite gel and comes in a little bottle from the hardware store here in the US at least.
the shape of the bottle tip and thickness of the glue makes it really easy to lay a thick bead right down into the fret slot and then press the fret in with zero squeeze-out.
TGP ? Whazzat?
Frank, did some experiments with hot hide glue some years back, and I was surprised to learn from him that it has much better heat resistance than the poly vinyl glues (Titebond et al), and probably than CA---acrylic plastic when set up. Perhaps FF could say whether that applies to fish glue as well.That could be another reason for using CA---to make frets easier to remove.
a much bigger forum than this one, a bit more electric guitar-oriented, but still a wealth of really good stuff for builders and repair guys, i've learned quite a bit there over the years from masters like john suhr and terry mcinturff.
here's one relevant thread
(oh, and FF's oven experiments with hot hide are what showed me the way to using it for those jobs a long time ago too)
I decided to check with Trevor Gore on this topic, and he very kindly responded with the following:
"Regarding gluing in frets, it depends on how good your fretting technique is. The test I use is to take a medium sized, flat-head screw driver and drop the tip from ~ 6mm up on to each fret under each string position and listen for the “ring”. (Wooden-handled screwdrivers, if you’re old enough to have one ;-) , give a better ring). Frets not properly seated in a location sound dull compared to other positions on the same fret or other frets. Mostly, you can’t see any difference in how the fret is seated. If you get 100% pass mark in this test, there is no need to glue in the frets. I reckon I have pretty good fretting technique (I press in frets and never dress them, because they are level enough not to need it). And I glue them in. Also, in varying humidity, fretboards expand and contract in length with the weather (causing varying degrees of back-bow/relief depending on where you started) which can “jack out” the frets over time. Gluing in the frets helps prevent this. I use normal Titebond to glue in the frets and run a fine bead from a fine nozzle over the fret slot and then press the fret in on top. The Titebond lubricates the fret in. If I’m being really pedantic, because I fret the board off the neck, I can clamp it in slight positive relief overnight, which means the barbs have time to press into the slot sides and set there, and the board comes out flat in the morning (no back bow) ready for gluing to the neck.
If I ever need to replace a fret, the soldering iron trick means it comes out pretty easily and the set glue in the end grain of the wood helps prevent chipping-out.
EVO fretwire (my preference) has short tangs compared to other stuff around and also a radius between tang and crown (as do most wires) so a bevel on the top edge of the fret slot is necessary. The EVO therefore needs good technique because there is not much grip length for the barbs and gluing helps a lot. The Titebond sets harder than the wood and I don’t buy into the arguments about it creeping etc.. If used right, with a thin glue line, it works at least as well as any other glue."