F-hole crack, self repair or expert & which glue to use?

[Gsouth]

Good morrow fair gents!
And ladies.


My Eastman 305 has recently developed a crack, about 1" long, running down from the F-hole on the G-string's side.

I recently moved to Namibia, where the relative humidity over the last 4 months was hovering around 13%.
I started a new job, and with the move and job etc. I kind of forgot about humidifying my mandolin, I hadn't been playing it since I got here.

I was rather alarmed when I took it out and noticed the crack, which seemed rather significant at the time, as the 2 sides were not aligning, and there was a noticeable gap, but after re-humidifying it over the past few days, the crack has practically disappeared, there is only a very fine line on the surface, and when pressing it, it wont budge.

I hope this means that it is a relatively minor crack because, as far as I can tell, there are absolutely no Luthiers in this country, every music shop I've contacted, I ended up needing to explain to them that there exists a person who's sole craft and passion consists of the making and repairing of stringed instruments, and that this person is referred to as a Luthier.

Im hoping that those of you with a lot more experience that I have, would suggest that I can attempt to repair it myself, without a high probability of ruining it permanently.
I obviously have no experience repairing instruments, but I am generally very capable with these kind of things.
I am an Architect by trade which means many, many hours of model building, mainly with cardboard and balsa, I also do leatherwork (not that that would help here at all), some elementary woodwork (ive built a desk, few chairs and bedside table) and I've built a few model planes and ships.

I've read a few other posts about repairing minor (which I hope this is) cracks.
I am afraid that hide glue is just about as difficult to get a hold of here as a Luthier (When contacting a hardware store, I end up explaining to them that you can make glue out of animal hooves, horns, bones and tendons)
From the replies Ive seen to some of the posts, it seems like it is generally acceptable to repair a crack of this kind with "superglue".
But, I have also read somewhere else that a Luthier would not make a repair that cannot be undone with relative ease by the next Luthier (which makes me nervous about the "superglue").
I can also get my hands on regular woodglue (the white, water soluble stuff).

Ps. Another question I have (although I dont know whether I should open a new thread for this), Ive read somewhere in the forum that sound hole humidifiers can actually damage the instrument more that it preserves it.
Why is this, should I be worried, and what can I do to avoid this?
It seems like I will not be able to go without a humidifier as long as I stay in Namibia, but I really dont want to unknowingly cause more damage to my mandolin.
Because a commercial humidifier is also a difficult thing to get a hold of here, I basically have a small plastic container with holes punched in the top, filled with damp (not wet) cotton wool, which Ive been checking every few days and then re-dampening it when its dry.

Any advice would be so helpful, I really am worried about my mandolin, it has been such a joy over the last few years, I really dont want to lose it.

Thanx for the great forum and in advance for any replies

Sorry for the long letter, If i had the time, I would have written a shorter one

PPS. I tried to attach a good photo, but it is really difficult to see the crack, so I hope the photos are helpful.
The shiny area around the crack has been there since I received the instrument from one of the highly regarded mandolin retailers that advertise on this site.
I noticed it and reported it to them immediately after receiving the mandolin, because I thought it might have been a crack that had been repaired (which it now seems like it is, which is weird as this was supposedly a brand new mandolin, which they personally set up and inspected before shipping it to me).
But because it would have been such a hassle to ship it back to the USA from South Africa, after it already took 3 months to get here, and then wait another 3 months for a new one, I basically settled on a 10% refund, hoping that it would not cause me trouble (which it now is), because they said that they doubted it was a crack, and I trusted them.

Is something like this a normal occurrence on a brand new mandolin, or only from some stores, or only from eastman?

Thanx again guys.

[HoGo]

I was going to write that use of CA (superglue) may leave shiny spot in your satin finish and after seeing the pics I'm pretty certain that that's what you have there... Either smudge of CA or finish overpolished after glueup of crack.
Now, since the crack possibly was contaminated by unknown glue I would give the CA another chance, BUT I would use masking tape right at the very egde of the crack form bothe sides, two strips virtually touching each other in spots. force the crack open with gentle finger pressure from inside, apply some glue and remove the pressure. You can wipe glue from the tape immediately and then remove the tape. Let the glue cure fully and then remove the strip of glue with "safe" razor blade scraping slowly without touching the surrounding finish. Look up Frets.com for this scraping. Apply some cleat underneath. You can use thicker superglue for cleating and apply with gentle finger pressure (index against thumb). You may try to remove the shiny spot by bentle rubbing with fine steel wool or 600-800 grit sandpaper but results depend on what type of finish is there - either true matt finish or just sprayed and unbuffed shiny finish which will get shiny in spots sooner or later.

[mandroid]

May have been there inspector declared "Not going anywhere" called 'Good', ship It !

may not have to do anything ..

Dental mirror .. to see inside make a Little tiny diamond* (4 sided ) piece of wood to glue across the Crack so It won't spread .

* not to be confused with the Carbon Crystals they dig out in Mines there ..

[sunburst]

I've used superglue for this type of crack with good results on at least one mandolin (a Nugget included) with a "satin" finish, and the result was invisible. When the crack is tight and correctly aligned, the CA can be applied to the underside edge of the top in the f-hole with a capillary tube and allowed to wick into the crack until it just fills, then stop. No CA will be above the surface of the finish if the application of the CA is stopped exactly when the crack is full.

[Gsouth]

Thanx for the replies so far.

I was hoping I could avoid cleats if at all possible.

I read a post by Paul Hostetter in another thread (here are a few excerpts):
"The longer I do this work (43 years and counting), and the more cleat failures I see, the less inclined I am to use them at all. The wood movement eventually overcomes the glue joint because the pieces of wood are fighting each other. Sometimes this is no big deal, but in some instruments, those loose chips of spruce become built-in buzzers you cannot reach without removing the top or back. And to add insult to injury, you realize they've really accomplished nothing anyway: the crack remains closed no thanks to the cleat, and the cleat is now the problem. This happens all the time.
I almost never use wood cleats, or any reinforcement for that matter, on carved plates such as violins or mandolins. They're the most likely to fail, and they offer little benefit even in the short term."
And then he mentions exceptions such as major structural cracks and sound post cracks.
Given, he was talking about a crossgrain cleat, but it does seem like he has a real concern with regard to cleats.

What I am especially afraid of is, if I do a cleat with the CA, and I do it incorrectly or it starts coming loose later, then that might cause an even more serious and more difficult problem to fix.

In your opinions, would cleats be necessary/advised for this crack?

John, how does one gauge when the crack is completely filled with the CA, in order not to apply too much?

Thanx again guys.

[sunburst]

In your opinions, would cleats be necessary/advised for this crack?

John, how does one gauge when the crack is completely filled with the CA, in order not to apply too much?

1- If the crack is tight and well aligned I would probably not use a cleat.
2- As in most things, experience helps. We learn to recognize what we see if we look closely at the flow of CA from the capillary tube, and as we look at the surface of the crack. You can sort of pulse the CA by applying and withdrawing the CA source. That gives you an idea what it looks like as the CA flows into the crack and what it looks like as it continues to flow farther into the crack when the source is withdrawn. When the whole length of the crack looks like the edge part right after you apply the CA, it's full. If you add more and there is suddenly too much CA, you can then wick some back out by applying something absorbent to the edge of the crack where the CA was applied. We have to be expedient with all this because we don't have "all day" when working with CA, but we don't have to be in a rush.

There is a common CA crack repair technique for instrument cracks where the crack is masked off to each side and the CA is applied to the surface and allowed to wick into the crack. After the CA has cured, the raised line of CA is then scraped, sanded and buffed level with the surrounding finish. That technique is pretty much strictly limited to high gloss instrument finishes, for obvious reasons, and would not give good, minimally visible results in the case of a "satin" finish, but when the crack runs out to an edge, like in the f-hole, the CA can basically be applied from below the crack surface, and that is the procedure that I've outlined above.

[Gsouth]

Thanx for the explanation John, I appreciate it.
I will probably try this tonight.
Do you possibly have a photograph of what the capillary tube looks like?
I want to see if I can find something similar in the stores around here.

[sunburst]

They're actually called pipettes, but the tip will function as a capillary tube. They're plastic, and a little practice to see how it works before applying the CA to the mandolin is a good idea.

[allenhopkins]

Leaving crack repair discussions to the experts, the only way of which I'm aware, that an in-case humidifier can harm your instrument, is if the moisture-retaining part of the humidifier -- sponge, fabric, whatever -- is in direct contact with the instrument's finish.

Soundhole humidifiers such as Dampit have a perforated rubber tube with a moisture-retentive material inside. Once the "wick" inside is soaked, the outer tube should be wiped dry before the humidifier is inserted into the soundhole. If the water doesn't contact the finish, should be no problem.

A small additional consideration with Dampits is that they may have a clip, which is supposed to be attached to the edge of the soundhole to position the humidifier inside. This clip can definitely scratch the finish, if not handled carefully.

In some ways a soundhole humidifier is preferable to separate humidifier in the instrument case, since it releases its moisture inside the instrument, where it presumably will be more readily absorbed by the unfinished wood surfaces inside. However, the difference may be trivial. A good in-case humidifier, whether bought commercially or jerry-rigged from a sponge and a perforated soapdish, will do the job. If you're right about the 13% humidity, it'd make sense to check the humidifier daily. Also, if you can obtain distilled water, that will avoid mineral deposits left behind when "tap water" evaporates; these may show up on the mandolin, and also my diminish the absorbency of the humidifier's water-retaining material.

[Denny Gies]

Gsouth, listen to John, he really knows what he's talking about.

[Bill Snyder]

Allen on more than one occasion Paul Hostetter has expressed dismay at the idea of in case humidifiers. I am too lazy at the moment to search for them. Perhaps he will explain the dangers again. I do remember that he is all for keeping your instrument properly humidified. This is to be done by humidifying your living space.

[allenhopkins]

...Paul Hostetter...is all for keeping your instrument properly humidified. This is to be done by humidifying your living space.

-- And I am too, which is why my instruments stay in a basement "cave" all the time, a room that has to be dehumidified all summer.

However. Gsouth is in Namibia; may be difficult to "humidify living space" in the Namib or the Kalahari.

[Gsouth]

Thanx for all of the replies guys.

You are correct Allen, humidifying an entire room here is a bit of a challenge.

John, I tried letting the CA wick into the crack with a pipet like you explained, but I think that the crack might have been too tight, I used the most liquid/flow-able superglue I could find, and it might have wicked in for a few mm, but definitely not into the entire length of the crack.
I then tried applying a little pressure to the top of the crack (so it would open slightly on the inside) and apply it along part of the length of the crack from the inside, as far as I could reach.
I don't know how far I got because I cannot see inside and I do not have a dentist mirror, but the crack was very tight and seems to be stable for now, I think re-hydrating the mandolin helped a lot, and I dont think it will budge as long as I keep the mandolin hydrated.
Could this slightly botched repair become a problem in the future?

Thanx again for all the help!