Identifying Cracks # 1

[Joshua Diaz]

What kind of crack is this?  By the way, this is a Breedlove AD25/SR with a Solid Sitka spruce top.

I found a similar crack on Frets.com.  Are they similar cracks?

It says the following:

They are structural cracks, but will not affect the longevity of the guitar even if they are left wide open and not repaired at all. Spruce has very little strength across the grain, and the pull of the strings is never in that direction. So, lengthwise cracks have little effect on strength in this area, where the only force is with the grain. The wide bridge (now off the guitar) distributes the load across six inches of the spruce, so it's able to handle the tension very well.

Thanks

Joshua

[Joshua Diaz]

Just a side note:  I have no experience with identifying cracks.  I'm just a guitar player.

Joshua

[Ned Knepp]

I'm afraid that I don't know what you are looking for here, Joshua. If you're looking for an excuse to leave cracks in a guitar this might not be the place to ask. 

At the beginning of that spread, Frank says that most people know that cracks need to be repaired. The idea that old cracks might not be structurally dangerous doesn't mean that they shouldn't be repaired. 

 It's true that guitars sometimes get cracks that aren't particularly dangerous as far as the instruments stability is concerned but I wouldn't leave them like that.  Top cracks that cross a brace will create a weakness in the brace at that point and the edges of the crack are much more susceptible to warping. Cracks can run with changes in humidity or a small impact. They can contribute to chipping finish issues and may even effect the sound of the instrument by creating buzzing or just interfering with the propagation of vibration through the top.  

Take a look at the cracks in the second picture you posted, those are old cracks that have "moved" over time. Notice that the edges are not closed and that the reflection shows that one side is higher than the other. They are completely repairable not not nearly as easy to hide as they were when they first opened up.  Of course, people leave cracks in instruments all the time but, in my opinion, it's not a responsible way to treat an instrument. 

[Joshua Diaz]

Thanks for the info.  For my own knowledge, I was just curious at what KIND of crack it was.  I am planning to get it repaired this summer, since I am away now at college.  I guess I'll find out then. 

Right now, It's not a priority for me to repair it immediately considering that I'm not playing it as much as I used to, and I can't really spare the cash.

As for the instrument, it is currently sitting in it's hard shell case with a humidifier (in the case) to prevent further movement of the wood.  Additionally, it is in the music department in a room with a powered humidifier.  Thanks again Ned.

Lesson learned:  dorm rooms are not the best for wood instruments. 

[Thomas James]

Do the Breedlove cracks go all the way through? They look like possible finish check lines.

[Kerry Krishna]

 Joshua, are you asking if this is a lacquer crack or a structural crack?

 Sometimes lacquer WILL crack along this exact point and will only be in the lacquer.

 To tell if it is structural, put your thumbs on either side of the crack in the middle of the longest part of it, and gently alternate pressing down with your thumbs. you will see right away if the wood is rising on eitherside. Make sure you do it in a few spots so you don't for instance press directly on top of a brace which would prevent this test from working..

[Hesh Breakstone]

Looks like a crack to me from here.... :)

Reminds me of Cheech and Chong, oh, what's that......, looks like.......;)

I've been repairing so very many cracks lately after this record cold winter here in Michigan that this must be how a proctoligist feels.....

Anyway Ditto - cracks should be repaired if at all possible.  The longer they are left open the less likely they will be to close with humidification and instead will need material added.

You can tell if it is a crack by getting some Naptha and running a bead of it on the crack.  Look in the instrument with mirrors and if you can see the wet spot... from the crack... coming though on the inside it's an open crack.  The Naptha will evaporate.

Hope this helps AND if you live in a cold cliamte this winter the guitar is likely dry too and needs a humidifier.

[Robbie Collins]

Perhaps it's a wise crack.

[Andrew]

:D nyuknyuknyuk

[George Roberts]

I think that cracks can occur commonly in 3 ways:

1. Traumatic cracks (Who sat on my guitar?)

2. Humidity related cracks, as discussed above, and these are more likely to be seen in newer guitars.

3. Age related cracks.  Wood shrinks as it ages, and it shrinks much more across the grain than with

    the  grain.  This shrinkage goes on for hundreds of years, but more and more slowly with the

    passing of time.  Many older guitars have these kinds of cracks, and no amount of  humidification

    will reverse them.

Probably a lot of cracks are a combination 2. and 3.  I would guess that smaller guitars would be less at risk, but that ladder bracing would increase the risk.

The picture is the edge of a 200 year old cherry desk.  It shows the dramatic difference in shrinkage.  Cherry also happens to be one of the most shrinkage resistant woods.