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Hello,

I recently received a pre-war Dobro model 27 that's in pretty good shape but it does have a crack in the base of the fretboard above the body. I'm wondering if I should just leave it alone or try to repair/stabilize it somehow.

I'm not a repair guy, but I suspect you will need to pull the frets to close the crack, and maybe separate the fretboard extension from the top. I don't think there's a simple fix.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

First thing I'd do is let it get humidified, might be due to dryness. See how.much that closes it up and then go from there

In the repair world especially with vintage instruments sometimes less is more.

The cracks if the instrument has been properly humidified already can be filled as is with the frets in place, etc. 220 paper, thin CA, sanding precisely in the areas of the cracks with the paper folded around four times so it's flat and you don't make divots. Apply wet glue to the crack with pipette, sand, brush off, observe, repeat if need be. If there are any markers of another material be mindful to not sand that dust into your crack.... or the fret board either....

This is a very common malady that can affect even recent instruments and the CA and sandpaper method works great, is quick, does not require more invasive approaches and permits the Luthier to then say........next.

Fixing these is so very easy that we often include the job with a set-up if it needs it and at no additional charge. Takes me about 20 seconds to do each one and I'm a geezer....

This method is for solid boards, if by chance that board is a lighter color wood that has been dyed this approach may not be ideal.

Thank you so much for the replies. In this case, can superglue be used or is thin CA necessary?

Superglue is CA glue

There's just different viscosities available.

Yep CA is super glue but we like quality super glue that's fresh and comes in various viscosities. The very thin variety that wicks into cracks easily is what I like for this job.

The shrinking action of hot hide glue can be used to pull narrow cracks together. Hot hide glue is non toxic and fully reversible.

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http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain

This is not a situation where you want reversibility or pulling together of cracks.
Its just a fill job and CA /sanding dust provides a great repair.
I would not Humidify before the fill either, that just sets it up for future problems.

Exactly!

I'll add that I was very much an anti-CA sort until I started doing repair work. CA has it's uses and for those things it works very, very well.

Why don't you want to pull the crack together or to properly humidify? On vintage instruments the most invisible repair is generally the best. Ether method works. I just prefer a non toxic solution as super glue is actually very toxic and I like to avoid using it at all costs. I was just offering an alternative method.

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http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain

Filling is preferred to rejoining because the wood has shrunken and suffered permanent dimensional loss. Forcing it back together would not only leave it sprung and loaded under tension with pretty much 100% chance of coming apart again, but would also result in a significant modification of altering the dimensions, leaving the board narrower than original. You could perhaps spline the center, but again, the prep work, fret removal, cleaning of the slot, etc, would not make for a less invasive method. A CA fill ends up being a wonderful confluence of least invasive, best for preservation goals, and at the same time one of the simplest methods.

As to toxicity, aside from the vapors acting as a mild irritant while curing, it's actually among the more benign adhesives out there. It's pretty much inert once dried, and the biggest health risk it may pose is usually gluing your fingers together.

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Eschew obfuscation, espouse elucidation.

I have used hhg on a narrow crack in a fingerboard like the one shown. It did close up the crack with almost no trace of the crack showing and it has been holding for 8 years now. I can see the need to fill a large crack but it should be noted that humidity alone might close a narrow crack like this one. Thankfully I don't do much repair work so I'm sure you guys know what works best.

_________________
http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain

Thanks again for the advice and thoughts on the topic.

Out of curiosity, independent of dimensional modification concerns, would hhg have the right viscosity to fill the crack?

Currently I'm leaning towards using the CA approach. I would think the instrument has settled in over the years and the crack should be stabilized, rather than introducing counter pressures to get it back to it's original form.

HHG is better used in cracks that you can get the glue into the crack easily and of course as Jeff said it shines for repairs that may need to be reversed in time. A fret board crack should never need to be reversed.

CA is also not toxic when dried and was developed to put on cuts to close them on a battlefield.

HHG is also thicker viscosity than thin, fresh CA making CA a better choice for when we need to wick it in well. CA and dust works very well, is fast and lasts.