An entry in the glue debate

I am not trying to start a fight. I cut the fret slots on a beautiful piece of bird's-eye maple and then managed to drop it, it is now cracked. The crack is a wild spiral and threatens to remove one corner.

Can I repair this or should I scrap it? I do not plan to sell the uke, it is to be a "cheap homemade uke." But if the fretboard is doomed to fail later I'd just as soon start over. On the other hand if it can be repaired with a fair chance of success I would like to do that.

This fretboard will be glued to a professionally-carved mahogany neck that I bought in a "seconds" box at the Mainland store. The neck and the fretboard are both concert-scale.

I have in my possession:
Epoxy (rapid-setting)
CA glue
Titebond
Elmer's Wood Glue Max

And I am willing to go out and buy a different glue. I would even be open to hot hide glue. But I will listen to all opinions. I do like the looks of this piece of wood.

What do you say?

I would use the thin CA and hold it tight until it totally cures, then carry on.

epoxy and CA will almost surely leave dark glue lines at the repair in Maple.. HHG is probably the most invisible. If it fits back together really well, you might be able to make an invisible repair with HHG. Wood glues can leave a good repair also. HHG is likely the most invisible.

Chris_H said:

epoxy and CA will almost surely leave dark glue lines at the repair in Maple.. HHG is probably the most invisible. If it fits back together really well, you might be able to make an invisible repair with HHG. Wood glues can leave a good repair also. HHG is likely the most invisible.

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Don't agree. I have had maple break and have made the repair right away with thin CA and you could not see any line or sign of a break. The CA is water thin so the trick is to not over do it and do not use the accelerator. Works for me.

I use CA for repairs too.. but with more mixed results. if there is any gap, the line can be very visible on light woods. I like how fast CA is for repairs. Since starting to use HHG in my shop, I have found more consistent, completely invisible repairs. I will use epoxy, CA, titebond, HHG, probably some caulking, who knows what else, again for repairs. Each situation gives a different challenge.

I'm with Chris on this. HHG just disappears and it takes stain and finish really well. You might get away with CA, but in my experience, it will show a glue line more than HHG. I've done HHG repairs that I could not find after the job was done. I can always spot my CA jobs.

This sounds like a job for household gelatin - like hide glue but with less hide (maybe), and available at the supermarket. It's the same animal proteins, but gels very fast, so is not really suitable for most gluing operations. Here, though, you could heat the corner of the fingerboard to stop gelling, work in the glue, clamp it all up and job done.

Mix up some gelatin and water in a cup (I'd guess 1 teaspoon of gelatin to 2 of water) and heat in a water bath until the gelatin is dissolved. You want around 150F, but temperature is not too critical here, as the fretboard will be glued to the neck so this joint is not structural. Get the water to where it is too hot to keep your finger in for more than a few seconds but not hot enough to hurt. Once dissolved, add water (1/4 teaspoon at a time) until it's like very runny honey. Heat, glue and clamp. Remove residue with warm, damp (not wet) paper towel.

Gelatin isn't just "like" hide glue...it is hide glue! Not sure of the gram strength, though.

You're actually in luck that it is birds eye maple. Whatever line (large or small, darker or lighter) remains after the repair, it should have plenty of other figure and twisty lines to hide amongst. I've been doing a lot of work with "highly eyed" maple this past year and it works very nicely with some patience. As this is a fretboard and will have support from the neck, there shouldn't be any lingering strength problems.

I suspect you will be able to glue it up and see for yourself before committing it to the neck. I'd go with HHG for no reason other than Rick said so.

Rick Turner said:

Gelatin isn't just "like" hide glue...it is hide glue! Not sure of the gram strength, though.

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I knew that, but wasn't sure if they left out "hide" because it's sold for human consumption. Not on edibility grounds, but because most of us might jib at a bit of horse skin in our dessert! Pork rind and beef crackling no problem, to non-vegetarians anyway.

The gram strength is very high - haven't checked Frank Ford's site but I recall he says around 400. I know from experience that it gels in about 10 seconds if you don't heat the workpieces. But for this repair it would be easy to heat the board enough to do the job.

Well it turns out that my maple is full of small spiral wavy cracks. I repaired it with CA and found the resulting repair "almost" invisible, and as stated above it is camouflaged by the figure in the wood. I trimmed it, fretted it, and glued it to the uke, whereupon glue spurted up through many tiny cracks that had been invisible before. So the wood is infested with cracks, but is now glued to a neck of nice, straight-grained mahogany and I am confident that it will remain sound. The cracks seem invisible, too, I could only detect them by the glue squeezing up through them.

I intend to learn hot hide glue use on my next project.

By the way I veneered the headstock with epoxy, the first time I have used it for that task, based on a different glue thread. The result seems very flat and very stable.