Dipped top

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Dipped top

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Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

Dipped top

Couldn't find anything on this particular issue so I decided to create a topic with pics.

Instead of a bump in the middle of the top/bridge, this guitar looks like a valley... it rises from the sides, then dips right at tie block area.

Is this ok? Surely isn't due to lack of humidity.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 7 2014 14:12:28

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Sr. Martins)

To clarify a few things:

The top was flat when the guitar was new.

The action is still the same, which means that it isn't really a dip in the center but two bumps, one on each wing.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 7 2014 18:01:45

Edzard

Posts: 20
Joined: Oct. 11 2010
From: Eindhoven - The Netherlands

RE: Dipped top (in reply to Sr. Martins)

Does your guitar have a bridge plate/patch under the top?

Regards,

Edzard

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 7 2014 19:44:12

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Edzard)

No, its just 5 thin fans, 4 of them almost parallel and the treble side one is diagonal.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 7 2014 20:17:21

constructordeguitarras

Posts: 1677
Joined: Jan. 29 2012
From: Seattle, Washington, USA

RE: Dipped top (in reply to Sr. Martins)

This is very unusual and I think not good. I think it means it was not braced properly. But if the guitar works, it must be okay.

What I mean by not braced properly is that the fan braces are too thin or were glued on with the soundboard flat instead of pushed into a scooped-out solera, which is how doming is achieved.

What make of guitar is it?

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 1:59:28

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: Dipped top (in reply to Sr. Martins)

I've never seen anything like that before. I can't even think of what could make the bridge go "concave" like that.

It must be that the top is very well braced under the tie block area but has little to no bracing out towards the bridge wings. Still... I don't get it.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 2:05:51

constructordeguitarras

Posts: 1677
Joined: Jan. 29 2012
From: Seattle, Washington, USA

RE: Dipped top (in reply to Andy Culpepper)

quote:

It must be that the top is very well braced under the tie block area but has little to no bracing out towards the bridge wings.

Andy, it seems the other way around to me: Not well braced under the tie block but well braced (domed) under the wings.

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Ethan Deutsch
www.edluthier.com
www.facebook.com/ethandeutschguitars
www.youtube.com/marioamayaflamenco
I always have flamenco guitars available for sale.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 2:07:51

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: Dipped top (in reply to constructordeguitarras)

quote:

Andy, it seems the other way around to me: Not well braced under the tie block but well braced (domed) under the wings.

You might be right, but that would seem to make more sense if the guitar was this way from the beginning. He said the top used to be flat, which makes it seem like it's pulled up at the ends of the wings since he got it.
Like I said, that still doesn't fully make sense though

I guess we don't yet know what the doming situation parallel to the grain is.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 2:19:59

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Sr. Martins)

In fact it has 6 braces, there are 2 on the treble side. The diagonal one is a long one that begins at the lower harmonic bar and then theres the second one which is shorter and has less angle (goes with the rest of the fan I guess).

The braces under the bridge are 3 very long ones. The middle one is perpendicular to the bridge and the other 2 are a bit angled.

The tie block almost hasn't been affected, just the wings.

Humidity has been very high since the guitar came and my house is being rebuilt on the inside.. that keeps even more humidity inside :/

The top is very thin and so are the braces (and shallow).

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 3:05:46

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Dipped top (in reply to Sr. Martins)

I dont think this has anything to do with the braces.

This is a to much humidity case. The top has sucked up so much moist that it has grown and made some weird movements. You have to dry it out SLOWLY. If it dries to fast it may crack.

I´ve had a similar problem years ago a very rainy weekend where my dehumidifier broke and everything got very humid. I had 3 guitars hanging without bridges on on they sucked so much moist that the soundboard lifted up except at the centerseam and the result was something close to what Rui is experiencing (my guitars actually looked like the top of a heart (scary)). After 5 days when I got a new dehumidifier I took down humidity and the guitars found their original shape and ther there were no problems with them later on. I now always have a cheap little extra dehumidifier in the house. Just in case.

Rui, do something about it now. If not, it may warp. And tell us how it looks when its been dryed ot for at least a week or so.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 7:40:22

tijeretamiel

Posts: 441
Joined: Jan. 6 2012

RE: Dipped top (in reply to Anders Eliasson)

I think I have the same problem with my guitar being too damp.

quote:

ORIGINAL: Anders Eliasson

This is a to much humidity case. The top has sucked up so much moist that it has grown and made some weird movements. You have to dry it out SLOWLY. If it dries to fast it may crack.

How do you recommend to dry a guitar?

I have a room dehumidifier, should I keep the room in a dehumidified room for about 40-45%?

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 9:57:59

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Dipped top (in reply to Sr. Martins)

use a dehumidifyer and slowly go from whatever you have down to less. Guitars dont nee to be kept in 40-50% humidity. 40 - 75% Rh should not cause any problems if the instrument was built in a controled environment.

In cases where an instrument gets really wet and start changing its shape, its important to lower the humidity SLOWLY and go down to at least 60% (better 50%) for an extended period until the instrument is stable again.

If a wooden instrument was built very dry, it will suffer more from humidity. It is a compromise. Luthiers from regions where it gets very dry in winter, often build at 40 - 45%RH in order to avoid cracks in the guitar later on, but its not the best for guitars living in humid areas.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 10:23:10

El Kiko

Posts: 2697
Joined: Jun. 7 2010
From: The South Ireland

RE: Dipped top (in reply to Sr. Martins)

To give the Luthiers a better idea of the inside layout ..put a light in side the guitar and take a photo and then we can see the strut, bridge and the internal layout ....

maybe might help to visualize the problem

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 11:02:29

Andy Culpepper

Posts: 3023
Joined: Mar. 30 2009
From: NY, USA

RE: Dipped top (in reply to Sr. Martins)

quote:

Humidity has been very high since the guitar came and my house is being rebuilt on the inside.. that keeps even more humidity inside :/

Right. That probably has something to do with it.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:24:15

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

It's either the top or the bridge- The bridge could be recurving or the top could be so swollen it is trying to find a place to travel and instead of popping up it's heading down.

The bridge could have been not dried enough to build with and if the moisture in the air changed radically the bridge could have reverse curved down instead of up. Usually a top and bridge will move in the same direction because the top is thinner and the bridge and tension of the strings will direct it to move in the direction of the arch. It's very common for flamenco guitars to have a high arched bridge and then a dip at the end of the bridge wings before the top raises up to the edges of the guitar. You can see this if you put a straight edge behind the bridge.

But this is the opposite and it brings up the question is it the bridge reverse arching and leading the top into deformation? Or is the top taking the bridge out of shape? One thing is sure the bridge and the top are not in agreement about who is boss, but it seems like the bridge is winning the fight.

The string tension on a typical flamenco would normally pull the top up into a posture where the back of the bridge is being pulled into an arc and the front of the bridge is being pushed down. So string tension usually helps shape the back arc of the bridge, it's odd the top is moved from it's normal position against the strength of the pull of strings so it leads one to think maybe the bridge is the active component causing the excess reverse arc. It could be avery strong willed piece of wood in the bridge.

Or the top is really dry and not full of moisture. (Dr. House would got for this gambit)

Or the bridge was somehow exposed to moisture and then to heat and dried quickly and stayed in that position, despite the overall humid conditions.

Was there anytime the guitar was exposed to excess heat while the humidity changed? Hopefully with moderate drying the guitar will reform, but if not, look into the bridge.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:31:00

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Sr. Martins)

Right now the guitar has slackened strings and the dehumidifier running. Today is a sunny day so the R.H. is already lower than the last 15 days.

I found pics I took a day or two after the guitar arrived in january and it was like this at that time. The only pics where I can see a completely flat top are the ones which were taken on it's country of origin.

I'll leave the dehumidifier running for now... in a few days/weeks the humidity will be much lower.

I can even feel the finish on the top... it's smooth everywhere, except at that valley created by the two humps. I can feel rugosity, the grain of the wood.. that area is compressed in a concave way so that should be expected.

From the side everything looks normal for a guitar that's supposed to be flat (I guess

)

Thanks for all the help and suggestions. I know Anders is in spain so he must deal with a climate very similar to this, what he says makes perfect sense.

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Attachment (2)

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:34:56

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

quote:

found pics I took a day or two after the guitar arrived in january and it was like this at that time. The only pics where I can see a completely flat top are the ones which were taken on it's country of origin.

If your guitar arrived with a completely dead flat top it was not constructed exactly the right way. It should have had an arch behind the bridge- are you sure it was _flat_ ?

If it was dead flat, then this issue is not as much of a mystery. Normally the top has arch build into it to keep it from becoming flat or reversing itself.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:44:02

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to estebanana)

quote:

Was there anytime the guitar was exposed to excess heat while the humidity changed? Hopefully with moderate drying the guitar will reform, but if not, look into the bridge.

Recently we had a sunny week or two where the R.H. dropped to 45%.

The thing is that with the pics early pics I've found out that the guitar developed that shape since I unwrapped it here at my house. It absorbed humidity really quick, the action changed from around 3A.M. to 12P.M. of the next day.

I thought that maybe too much break angle and the saddle angling backwards wouldn't help right now so I removed the saddle. I might tie the strings as a 6 hole instead of 12 (as it is right now) to reduce torque.. am I thinking right?

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:44:16

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to estebanana)

quote:

If your guitar arrived with a completely flat top is was not constructed exactly the right way. It should have had an arch behind the bridge- are you sure it was _flat_ ?

Iam not sure but compared to anyother guitar I've had or played, this was pretty flat to me.

Pics from the guitar on the country it was made:

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:49:05

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Dipped top (in reply to Sr. Martins)

leave it in peace in a moderately dry environment for a week and see how it looks.

If it still looks like this then, then there´s a problem in the construction. maybe the bridge was glued on with a different humidity than the humidity that were when it was braced and assembled.
Have you contacted the seller or builder?

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:53:44

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

Don't look at fan braces or break angle-

This is more about the top and bridge and how they were glued together and under what moisture conditions. Other factors come into play like whether the bridge was arched underneath or glued on flat What humidity level the bridge was glued on at and how the bridge wood was seasoned. And how the top was braced under what humidity, more for the sake of the top than the braces.

It's probably more a combination of those factors. Hopefully the guitar will reach equilibrium again. Which means it might go back to being flat. Which is to say it might not even change the way it sounds. This might just be the structure of that guitar and it lives that way, it it was constructed with those abnormalities.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:54:54

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Sr. Martins)

Pics from the day the guitar was finally at my house.

Beware that it's a two piece golpeador when looking at the bridge/saddle reflection over the top on the second pic.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:56:57

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

You can't tell anything from those pictures.

But as the Aussies say, that's a totally horny red rug, ever bumped your girlfriend on that thing?

The other photos of the bridge, bridge looks suspect, it does not have the hallmarks of a smartly made bridge. The wood looks odd, not ebony, which is not a great selection for bridge wood , but something dyed or a strange dark wood. Sometimes factories make bridges out a of a lighter wood and dye them dark, this can be a problem because the dyed woods are often susceptible to changing shape.

I mean just to be nickpicky and go over all the things that could have happened, poor materials choice or materials failure is not something you should rule out.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 12:59:38

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

And I always beware of two piece golpeadors...never know when they will attack.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 13:07:41

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to Anders Eliasson)

quote:

Have you contacted the seller or builder?

The builder is the seller (sort of) and I might show them this thread because when I got the guitar and the action changed overnight (was already too low when I first looked at it), I emailed them inquiring about this and if the neck angle was supposed to be so flat (I guess it is, either way I like it like this, strings almost parallel to top).

Still waiting for an answer since january.

Don't know if this is the case for such assumption but I was getting replies much faster when I had only payed for half of the guitar

Anyway, it sounds great! I just don't want it to implode in a near future :/

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 13:08:17

estebanana

Posts: 9365
Joined: Oct. 16 2009

RE: Dipped top (in reply to Sr. Martins)

What country pray tell did this instrument come from?

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 13:10:05

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to estebanana)

quote:

But as the Aussies say, that's a totally horny red rug, ever bumped your girlfriend on that thing?

The other photos of the bridge, bridge looks suspect, it does not have the hallmarks of a smartly made bridge. The wood looks odd, not ebony, which is not a great selection for bridge wood , but something dyed or a strange dark wood. Sometimes factories make bridges out a of a lighter wood and dye them dark, this can be a problem because the dyed woods are often susceptible to changing shape.

Nope but I'll do that for you..althought it's right next to the bed

It's indian rosewood. It looks funky because it's the only part of the guitar with a matte finish. The rest is glossy thin nitro.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 13:13:01

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to estebanana)

quote:

What country pray tell did this instrument come from?

Bulgaria.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 13:14:17

Sr. Martins

Posts: 3079
Joined: Apr. 4 2011

RE: Dipped top (in reply to estebanana)

quote:

Don't look at fan braces or break angle-

Here's why I mentioned that I might be using a lot of break angle. Also shows the back angled saddle design.

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Attachment (1)

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 14:37:49

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Dipped top (in reply to Sr. Martins)

Thats not a lot break angle and it shouldnt cause any problems at all.

Its unethical to write this on a forum before contacting the builder/seller. I´ve seen lots of trouble because of stories like that.
If someone wrote things like this on a foro about a guitar that I had built them before contacting me, I would get SERIOUSLY pissed off and i would not be as kind and helpfull and interested in sorting out things as I normally would.

Without having seen your guitar, I have a feeling something went wrong during the building and it could very easily be because the instrument was built under to many different humidity conditions. If thats right, there´s basically no easy solution

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 8 2014 17:13:28