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Crack from dry humidity won't close up.   You are logged in as Guest
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JasonM

Posts: 1804
Joined: Dec. 8 2005
From: Baltimore

Crack from dry humidity won't close up. 

I asked about a crack in my guitar where the top pulled away from the fingerboard.
There are pics in this thread:

http://www.foroflamenco.com/tm.asp?m=269301&p=1&tmode=1&smode=1



The crack has not closed. I have been humifying the guitar with a sound hole sponge in its case. the weather has warmed up for a month or so. So the air is no longer dry.

Is there anything I can do to close this crack.? wondering if the guitar needs extra moisture since it was so dry. I've even read about repair shops sealing up a guitar in a trash bag with moisture so that it can rehydrate.

Thanks
  REPORT THIS POST AS INAPPROPRIATE |  Date Apr. 28 2015 22:09:07
 
HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Crack from dry humidity won't cl... (in reply to JasonM

Edited for your reading pleasure and correctness:

quote:

Anders

RE: Crack from dry humidity won't cl... (in reply to JasonM)

I would suggest more or less what i say.
Humidify the guitar slowly and then keep the guitar in a stable place. Better slightly humid 60 - 70%rh than dry and see if it closes. If it doesnt do so within some month/half a year, it most probably will never do so and then the standard repair will be to make a small splint to insert in the crack and maybe a few cross-grain patches (diamonds) on the inner side just like you said.
Another solution is what John Shelton wrote in the first thread about this guitar: "ignore it" Most probably it wont affect sound and the upper harmonic bar will stop the crack from splitting down through the rosette.
But if you one day want to sell it, then cracks like this push down the price a lot. Guitarists are very crack sensitive....



And here is my original post for historical context:

A crack along the fretboard like that is super common. If a case humidifier doesn't do the job then I suggest a bit of the method [I have learned from luthiers and violin makers]. As follows in grossly oversimplified form:

Get a plastic garbage bag and a [humidification source like a sponge]. Insert guitar and [humidification source] into garbage bag. place on flat surface that won't be disturbed. [monitor humidity and progress closely and watch that you don't over humidify or humidify too quickly].

This should bring your Relative Humidity up and swell the crack shut. you can then get some small cross grain spruce patches and some hide glue to repair the soundboard from the inside. Let that cure. [At this time you should carefully monitor the humidity once again and slowly reduce the level back to normal if you have exceeded it during the repair]

Remove guitar from bag and put back into well humidified case to acclimate slowly. Don't [try to play or restring it] for a few days. The crack will not likely reappear after this. It will be stable.


I'm sure there is a veritable cornucopia of ways to accomplish this repair and twice as many people saying that my method is wrong. No sweat though, it's used to repair priceless violins as well so there's some precedent.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 3 2015 14:53:34
 
jshelton5040

Posts: 1500
Joined: Jan. 17 2005
 

RE: Crack from dry humidity won't cl... (in reply to HemeolaMan

quote:

ORIGINAL: HemeolaMan

A crack along the fretboard like that is super common. If a case humidifier doesn't do the job then I suggest a bit of the old R.E. Bruné method. As follows:

Get a plastic garbage bag and an open container of water. Insert guitar and container of water into garbage bag. place on flat surface that won't be disturbed. Wait a week.


Nothing wrong with this method but one needs to check on the guitar at regular intervals rather just specifying a week. When you over-humidify a guitar other things can happen like blowing the bindings off because of expansion of the top wood. It goes without saying of course that you take the strings off before putting it in the garbage bag.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 3 2015 18:10:34
 
Ricardo

Posts: 13331
Joined: Dec. 14 2004
From: Washington DC

RE: Crack from dry humidity won't cl... (in reply to JasonM

all that humidity "cure", what do you think will happen after the fingerboard dries out AGAIN?

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 3 2015 18:54:35
 
HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Crack from dry humidity won't cl... (in reply to Ricardo

quote:

all that humidity "cure", what do you think will happen after the fingerboard dries out AGAIN?


What will happen is that he will, of course, be sure to keep his instrument at a proper humidity from now on. Provided he does that, the cross grain patch will swell and contract perpendicular to the grain of the top with changes in humidity. It will not split open again unless there is significant structural issues that cause undue downward pressure on the end of the fingerboard.

The issue isn't so much about the fingerboard drying out as it is about the natural weakness of a soundboard in that area. A significant portion of the soundboard is covered in glue and fingerboard on one side of the top. On the underside it is exposed raw wood that expands and contracts at the same rate as the wood around it. The differential moisture absorption here can cause a split. You might notice that there is often a brace across the area in many guitars. I call it a "popsicle stick" because it looks like a popsicle stick. Very common on steel strings too.

There are other factors too, but that is a common cause of this type of crack.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 3 2015 21:14:28
 
Escribano

Posts: 6321
Joined: Jul. 6 2003
From: England, living in Italy

RE: Crack from dry humidity won't cl... (in reply to HemeolaMan

quote:

A crack along the fretboard like that is super common. If a case humidifier doesn't do the job then I suggest a bit of the old R.E. Bruné method. As follows:

Get a plastic garbage bag and an open container of water. Insert guitar and container of water into garbage bag. place on flat surface that won't be disturbed. Wait a week.


Richard Bruné has written to me on this attribution and I post his comments as follows:

quote:

It was brought to my attention that comments attributed to me were made in the lutherie section of the Foro in reference to a method to re-humidify a shrunken fingerboard in which I purportedly suggested raising the humidity level of the instrument to 100% by placing it in a sealed bag with wet sponges. Not only is this not accurate, it is very dangerous and will lead to more damage of the instrument. Fingerboards are very slow to give and receive humidity and can only be re-humdified to original equilibrium very slowly. The original poster would be well advised to take the instrument to an experienced luthier for thorough examination and expert advice.


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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 4 2015 17:24:03
 
Anders Eliasson

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Joined: Oct. 18 2006
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

Now, that was a good reply.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 5 2015 11:44:11
 
jshelton5040

Posts: 1500
Joined: Jan. 17 2005
 

RE: Crack from dry humidity won't cl... (in reply to Anders Eliasson

quote:

ORIGINAL: Anders Eliasson

Just sad we dont have so many experienced professional posters on this forum. Here it very often ends up in cerebral infight between persons with little real-world knowledge and the result is often..............

No need to be insulting Anders. Hemeolaman has posted here many times and appears to be a skilled craftsman. I'm sure crediting Brune with this method is an honest error. Humidifying a guitar with this method is a common practice that's been used for many years. I have used it several times in the past with mixed success.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 5 2015 14:21:47
 
Ruphus

Posts: 3782
Joined: Nov. 18 2010
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

Anders,

You seem to be complaining this way since years.
What is it that you expect? A pure luthier forum; and would "real-world knowledge" (whatever that is supposed to be looking like), defy from mistaking or from controversy about guitar specifics?

I doubt it.

If you have an aversion against mistaking, also better don´t post yourself, for there is no living without failure. - Rhetorcially meant. Keep posting and be a bit relaxed about what may be or appear to you like lesser informed.

Ruphus
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 5 2015 18:10:37
 
estebanana

Posts: 8324
Joined: Oct. 16 2009
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

Real world experience often comes on the heels of failure. True. And before you can fail, you have to have a concept or an idea of which route to try to fix the problem.

Good thing some people can work these conceptual problems out in public by discussing them, and getting feedback on the good and bad points of the idea. This kind of judgment can be embarrassing and difficult to take, but it serves to make the shop practices better and more careful by all who read.

No harm done I say. Lets not recriminate people for trying out ideas, because they probably learned something from the process of posting and having their idea subjected to a critique. And it looks like enough authorities are watching and reading and would send a good and swift critique if they observed a real problem about to happen.

In addition to the regular talented makers who post here, we are fortunate to have some of the best known authorities in the business occasionally contribute to the knowledge. So this is a good place to test out ideas and see if the really float or if they have holes in them.

______

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 6 2015 0:55:27
 
keith

Posts: 1108
Joined: Sep. 29 2009
From: Land of Daniel Boone

RE: Crack from dry humidity won't cl... (in reply to JasonM

I am not a luthier so I cannot comment about the effectiveness of the garbage bag technique. I do agree with Mr. Brune's primary point that his name was used in error to validate the garbage bag technique. I suspect Mr. Brune would not have jumped into this fray had his name not been used.
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 6 2015 8:59:10
 
HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Crack from dry humidity won't cl... (in reply to JasonM

I should add that the instructions in my post are paraphrased from an email conversation many years ago. They are too generic and that is my fault. There are some important details I left out for sure. Tell me you haven't done the same on your posts once in a while! I posted a simplified version of the methodology. The expectation I had, and perhaps my wrongful presupposition, is that someone asking a question in the lutherie section had some knowledge of lutherie or wood working. It was not my intention to post a complete and exhaustive "how to" on the matter and I assumed that the OP would use good sense and woodworking knowledge in conjunction with the general outline that I provided. This was my mistake and I should have been more clear for a mixed audience.

The subject of the conversation I had with [him] LONG AGO was not "how does one rehumidify a guitar in explicit detail including the fretboard" rather it was a conversation about something else in which he briefly explained his process for doing so. I expect that he didn't intend the description to be more than a basic summary of the process nor that I would use this information as a methodology for repair. Rightly so.

One other point, the discussion he and I had (at this point I'm thinking it was about 8 years ago) was not about rehumidifying a fingerboard. And indeed, I am not offering advice on fixing the fingerboard but the crack in the soundboard next to it. Our conversation was about backs, sides, and tops. Not finger boards. So if you ask him about it he will of course say that he never advised such a solution for fingerboard repair. Which is correct. He never once said that this was appropriate to fix a fingerboard and neither did I. And as such I have not quoted him directly and as you have seen he has supplied his rebuttal which clarifies his position on the matter.

Everyone is welcome to roundly debate and ridicule my position with their experience and facts. I make no claim to be an expert repair person nor am I a builder of exquisite instruments with years in the trade. However, no one has offered a solution for mister Jason, whose guitar still has a crack in it despite our efforts. I would've expected the experienced and highly reputed luthiers to have offered their counsel on the issue and a critique of my method. Instead I am dismissed as wrong without so much as an alternative methodology.

I don't mind remarks from Anders because this is an internet forum and any perceived personal differences we may imagine between us could be solved with a few beers and a good conversation. I would rather expect some good advice and some counter points to my position though. It's one thing to call me inexperienced and dismiss my ideas, it's another to just leave it at that without correcting me. I've been lumped into a a category of "cerebral infights" which I don't understand. I answered Ricardo's question with a technical explanation of facts about how the repair works and what the wood does... I don't think that he or I labor under the supposition that we are "fighting" in any way.


My second mistake was not emphasizing the other sources for this methodology. I will perhaps refrain from using names here. There are many exquisitely skilled world class violin repairmen in the chicago area. Several of whom I have access to on a personal level and have discussed these matters at length. I am not suggesting the method in my original post without due consideration of the advice they have given me in such matters. The method, or more detailed version thereof, works. I have repaired several guitars and other instruments this way. Maybe it isn't the best but there's three important facts about it: 1. you can do it in your home 2. it costs nothing 3. it works. Just don't screw it up!

I didn't learn to fix guitars and things made of wood by apprenticeship or by going into it as a trade. I learned it because I started playing guitar at age 8 and couldn't really drive to a local shop to get my guitars set up or repaired. For those of you counting I'm 27. I had a basement and some tools. Now I play over 20 instruments and make a variety of them in a pretty badass shop. I repair guitars, furniture, and other mechanical devices for both practical reasons and for fun. I'm not a luthier by day. I have no emotional stake in being right or wrong about what repair is best.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 8 2015 18:27:09
 
Jeff Highland

 

Posts: 401
Joined: Mar. 5 2010
From: Caves Beach Australia

RE: Crack from dry humidity won't cl... (in reply to JasonM

The fretboard is relevant here because this sort of crack is generally due to the fretboard shrinking and pulling the soundboard apart, rather than the soundboard shinking.
You may never get full recovery with humidifying.
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 0:02:29
 
Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

I have edited my first post. It was to harsh and could to easily be taken personal. I´m sorry for that and I opologize to Kevin (hemeoleaman) because it was not fair. On the other hand, there was and still is a reason to write what I wrote and deleted. But since its a more general opinion and not aimed at 1 or 2 persons, it was written in the wrong place.

Back to the crack
The problem with this plastic bag solutions is that when you humidify or dehumidify this radical way, then you are looking for trouble and sometimes serious trouble and advising people to do so is a very bad practice IMHO. If you leave the guitar in high humidity for a very long time then you may end up with serious structural damage. You may even end up with glue problems.
Yes, use a plasticbag with water sponges, but DONT leave it there for a week!!!!!!! A fingerboard could take month or more to suck up humidity and as Jeff Highland just said, the chance that it will go back to where it was is VERY small. Ebony is famous for schrinking and getting smaller not the oposite way.

The soundboard crack along the fingerboard is a very classical crack and cant be fixed well in a rush of time. Often, after having left the guitar to be stable it shows that it will need a small splint to close the gap. But DONT do so untill you are sure the guitar is stable and has been so for a very long time.

And finally, guitars and violins are pretty different beasts and in this contex, the main difference is that violins dont have their ebony fingerboard glued to the soundboard. So comparing in this example doesnt do anything good.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 7:33:16
 
HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Crack from dry humidity won't cl... (in reply to Anders Eliasson

I appreciate your revision, Anders.

It would seem that the plastic bag method is good for cracks in general but not for this variety of crack.

What would you suggest to resolve this issue? slow, regular humidification and a watchful eye?

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 16:14:14
 
Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

I would suggest more or less what i say.
Humidify the guitar slowly and then keep the guitar in a stable place. Better slightly humid 60 - 70%rh than dry and see if it closes. If it doesnt do so within some month/half a year, it most probably will never do so and then the standard repair will be to make a small splint to insert in the crack and maybe a few cross-grain patches (diamonds) on the inner side just like you said.
Another solution is what John Shelton wrote in the first thread about this guitar: "ignore it" Most probably it wont affect sound and the upper harmonic bar will stop the crack from splitting down through the rosette.
But if you one day want to sell it, then cracks like this push down the price a lot. Guitarists are very crack sensitive....

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 16:59:05
 
ngiorgio

 

Posts: 168
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From: Florida, USA

RE: Crack from dry humidity won't cl... (in reply to Anders Eliasson

What would cause a crack of that type to split through the rosette along the fretboard?
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 18:51:11
 
JasonM

Posts: 1804
Joined: Dec. 8 2005
From: Baltimore

RE: Crack from dry humidity won't cl... (in reply to JasonM

Wow I didn't expect a reply on this thread. Thanks Hemeola, I appreciate the advice and reply.

Well I am/ was planning to sell this guitar to upgrade. Even if the crack is fixed I still have to mention it of its repaired. So I was hoping a stay at re hydration rehab would help out.

I know better to put my guitar in a bag full of water or a dip in the bath tub lol. Yeah I have wood working knowledge but not Lutherie.

If I raise humid to 70% in its case for a while (this is what I was planning on my own), should I kick start the process with a bag? What would be the period of titration then? For example, do I shoot for 10% raise a day until 100 percent, then bring it back down?

Yes the crack was my neglect. I had a medical issue arise for a couple of years and couldn't play. I left the guitar in its case on the basement which actually was enough humidy. Later I brought the guitar upstairs as I started to play again on occasion but didn't hydrate it enough in the winter/s. I didn't notice it until I went to make modifications to the tie block, and give it TLC.
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 19:19:51
 
HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Crack from dry humidity won't cl... (in reply to JasonM

Thanks for the correction Anders!

I know of a product that will keep your case at a constant humidity level. It uses osmosis to absorb and emit humidity at a constant rate. They were originally manufactured for Cigar Humidors.

Boveda Humidification packs

There's several models of them, one of which D'addario uses in it's guitar humidifier thingie instead of sponges.

Comes in multiple humidity levels from 13% all the way up to 90something%. I believe they have a 50, 60, 65, 69, and 72. Those you could use to gradually step up the humidity in a very controlled way with little fluctuation. Very stable, very safe.Boveda Humidification packs

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 9 2015 19:45:45
 
Anders Eliasson

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Joined: Oct. 18 2006
 

RE: Crack from dry humidity won't cl... (in reply to JasonM

Jason
I personally wouldnt go up to 100%RH
The guitar may suffer seriuos damage because the soundboard will change shape and depending on the glue that has been used for its construction, that may also start loosening up.
Already at 80%RH during more than a week, a guitar that has been build at 50% RH start to change soundboard shape and I wouldnt go higher than that.
If it doesnt close after a month or two in a relatively high humidity, it wont close and either give it a splint or leave it as it is.
REMEMBER to let it dry out very slowly afterwards. Loosing humidity fast is the worst for wood.
This with selling and price: A well made repair in a zone like this one shouldnt affect value. It has absolutely no effect on sound or playability. But I know guitarists are very hysterical with cracks, so its difficult to make them understand.

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  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 10 2015 10:51:52
 
JasonM

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Joined: Dec. 8 2005
From: Baltimore

RE: Crack from dry humidity won't cl... (in reply to JasonM

Great , big thank you Anders!
  REPORT THIS POST AS INAPPROPRIATE |  Date Jun. 15 2015 18:04:41
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