A hairline top crack? (Pics)

Construction and repair of Classical Guitar and related instruments
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Arash Ahmadi
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A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 9:31 am

There's a hairline looking crack on my sound top. I am not sure whether it is a crack or not, I hope you could tell me that. I'm currently traveling and can't find a good guitar maker to have a look at it.

It starts from the lower bout below the bridge and continues as a straight line up to the rosette, between the 4th and 3rd strings, one wouldn't notice it by touch.

Here are some pics: https://files.fm/u/ws5egafe

Zooming in would probably be necessary to see it. I should be able to take more photos.

Please share your thoughts.
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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rinneby
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Re: A hairline top crack? (Pics)

Post by rinneby » Wed Jan 24, 2018 9:48 am

Arash Ahmadi wrote:
Wed Jan 24, 2018 9:31 am
There's a hairline looking crack on my sound top. I am not sure whether it is a crack or not, I hope you could tell me that. I'm currently traveling and can't find a good guitar maker to have a look at it.

It starts from the lower bout below the bridge and continues as a straight line up to the rosette, between the 4th and 3rd strings, one wouldn't notice it by touch.

Here are some pics: https://files.fm/u/ws5egafe

Zooming in would probably be necessary to see it. I should be able to take more photos.

Please share your thoughts.
I'm not sure what you mean? The "hairline looking crack" in the middle is just two pieces of wood glued together. Hard to tell from the pictures though if they have started to separate...

/J
1964 - Masaru Kohno No.7
1999 - Lorenzo Frignani
2017 - Tobias Braun

Feel free to ask me anything about Japanese classical guitars.

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 10:10 am

rinneby wrote:
Wed Jan 24, 2018 9:48 am
Arash Ahmadi wrote:
Wed Jan 24, 2018 9:31 am
There's a hairline looking crack on my sound top. I am not sure whether it is a crack or not, I hope you could tell me that. I'm currently traveling and can't find a good guitar maker to have a look at it.

It starts from the lower bout below the bridge and continues as a straight line up to the rosette, between the 4th and 3rd strings, one wouldn't notice it by touch.

Here are some pics: https://files.fm/u/ws5egafe

Zooming in would probably be necessary to see it. I should be able to take more photos.

Please share your thoughts.
I'm not sure what you mean? The "hairline looking crack" in the middle is just two pieces of wood glued together. Hard to tell from the pictures though if they have started to separate...

/J
No I don't mean that. It is in parallel with the joint line, more towards the 3rd string.
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 11:12 am

It's a very thin line, almost invisible.
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Michael.N.
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Re: A hairline top crack? (Pics)

Post by Michael.N. » Wed Jan 24, 2018 11:15 am

Hairline crack. You'll need an extremely good picture to have any chance of seeing it and even then I very much doubt you'll get a definitive answer. They are hard enough to see in person. 'Almost invisible' just about says it all.
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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 11:22 am

Michael.N. wrote:
Wed Jan 24, 2018 11:15 am
Hairline crack. You'll need an extremely good picture to have any chance of seeing it and even then I very much doubt you'll get a definitive answer. They are hard enough to see in person. 'Almost invisible' just about says it all.
Thanks Michael, You are right. It's almost possible to see when zooming in. But supposing it's a hairline crack. Is there something I should do immediately to prevent further damage?

Should I notice the the crack when I touch it?
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Michael.N.
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Re: A hairline top crack? (Pics)

Post by Michael.N. » Wed Jan 24, 2018 11:46 am

No you won't necessarily be able to feel such a crack. Just keep the guitar at the usual humidity until you can get it to someone who will be able to tell you whether it's a crack or not. Grain lines can be very deceptive, there's every chance that it isn't a crack but of course impossible to say. Take the tension off the strings too. The worst thing that can happen is if the crack becomes a much more open one and dirt/grime accumulates deep into that crack. That usually happens over a period of months though.
Historicalguitars.

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 6:28 pm

Here's another photo, but you really need to zoom in to see it. It's just below the 3rd string.

https://files.fm/u/j6eusa4g
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Michael.N.
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Re: A hairline top crack? (Pics)

Post by Michael.N. » Wed Jan 24, 2018 8:12 pm

I see it. I still can't tell you if it's a hairline crack, it could be a crack in the finish. It does need looking at though. What guitar is that?
Historicalguitars.

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 8:50 pm

Michael.N. wrote:
Wed Jan 24, 2018 8:12 pm
I see it. I still can't tell you if it's a hairline crack, it could be a crack in the finish. It does need looking at though. What guitar is that?
Right, it's a 2012 Hilhorst concert guitar. Could it stay without repair if it's in the finish?

Edit: It's hard to get a good shot from the beginning up to the end of it but it starts from the lower bout up until the rosette. A tiny bit deeper around the bridge.
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Wed Jan 24, 2018 8:55 pm

What I don't understand is how come it is such a straight line? It's almost like a grain. I read somewhere that they call it a "structure crack"?
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Michael.N.
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Re: A hairline top crack? (Pics)

Post by Michael.N. » Wed Jan 24, 2018 11:22 pm

If it follows the grain there's every chance it is a crack. You'll have to look closely, the grain on that soundboard isn't straight, if the 'crack' follows the curve of the grain then things aren't looking so good. If the 'crack' ignores the path of the grain then it's likely to be in the finish.
If it is a crack then at the moment it's far from being the worst type of crack to have. It's tight and can be made to appear virtually invisible with repair and perhaps finish touch up.
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SteveL123
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Re: A hairline top crack? (Pics)

Post by SteveL123 » Wed Jan 24, 2018 11:54 pm

Found this crack finding techniques:

"Put naphtha on the outside of the crack, all along the length. Then look inside with a mirror and flashlight. You'll see wet spruce."

Naphtha will evaporate and leave no trace.

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Thu Jan 25, 2018 9:30 am

Michael.N. wrote:
Wed Jan 24, 2018 11:22 pm
If it follows the grain there's every chance it is a crack. You'll have to look closely, the grain on that soundboard isn't straight, if the 'crack' follows the curve of the grain then things aren't looking so good. If the 'crack' ignores the path of the grain then it's likely to be in the finish.
If it is a crack then at the moment it's far from being the worst type of crack to have. It's tight and can be made to appear virtually invisible with repair and perhaps finish touch up.
I see. With a closer inspection I've realised that the "crack" is not only on one grain. About 5mm toward the end of the bout it separates to two lines! (the point where they separate looks deeper :( ) but up to the rosette it's only one line that very very gradually moves between 3 neighbor grain lines and as it gets closer to the rosette it gets less visible. Also the "crack" looks inward and can't be felt.

I should be able to post some more pics in about an hour.
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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Arash Ahmadi
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Re: A hairline top crack? (Pics)

Post by Arash Ahmadi » Thu Jan 25, 2018 9:32 am

SteveL123 wrote:
Wed Jan 24, 2018 11:54 pm
Found this crack finding techniques:

"Put naphtha on the outside of the crack, all along the length. Then look inside with a mirror and flashlight. You'll see wet spruce."

Naphtha will evaporate and leave no trace.
Thanks Steve, it sounds a bit risky for this guitar. Does it work with all finishes?
To send light into the darkness of men's heart, such is the duty of the artist. (Robert Schumann)

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