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  #16  
Old 10-16-2017, 01:31 PM
dekutree64 dekutree64 is offline
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By composite, do you mean carbon fiber tops?
I was talking about braces. And by composite, I mean any mixing of materials. Trevor Gore's falcate bracing is one of the best ways to use carbon fiber in braces. It uses one strip underneath the brace and one along the top, to get an I-beam type effect. Lighter weight and more creep-resistant than solid spruce. But it's tricky to get right because you can't carve material off the braces afterward to finetune the stiffness.

A less effective all-wood composite would be to glue a vertical strip of higher strength wood like purpleheart between two strips of cedar and then use it like normal. The tall skinny purpleheart strip would take the load, while the cedar just keeps it from tipping over. Probably would be slightly heavier than solid spruce, but slightly more creep resistant.

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So what I understand is that you have more bracing in the upper bout and it decreases as you go towards the lower bout. I would like to hear it. Any youtube vids?
Yep. As far as I can tell, the upper bout stiffness doesn't really affect the tone. https://soundcloud.com/user-58759988...-galaxy-guitar

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I thought that the double top was just a synthetic mesh attached to the top. I didn't think it would affect strength that much.
"Double top" is very different from "double sides". Both are just marketing terms, really. "Double top" usually refers to various methods of creating a soundboard with hollow spaces inside of it to lower the density. "Double sides" usually refers to gluing two pieces of solid wood together after bending, to make sides that are thicker than you can bend all at once.
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  #17  
Old 10-16-2017, 01:58 PM
HNS HNS is offline
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Thank you Truckjohn and dekutree64.... very informative!
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  #18  
Old 10-16-2017, 08:14 PM
CabinetMan CabinetMan is offline
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Alot of great information in this thread. Thanks for posting it.
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  #19  
Old 10-16-2017, 10:51 PM
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Thank you again for your help... I'm considering the Taylor 812 or 912 ... probably ....
Fwiw I have a 22-y-o Taylor that's had mediums on it since 1995. It's not showing any signs of neck angle issues. It is pretty responsive for a factory guitar, so it isn't too overbuilt.

I highly recommend mid-90s Taylors if you're open to buying used, and only the new revoiced models otherwise.
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  #20  
Old 10-17-2017, 01:06 AM
tadol tadol is offline
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Keeping your guitars well set-up and properly humidified helps alot too - letting small problems in action and set-up go without attention can lead to bigger problems very quickly. I think that traveling and not having a luthier or tech that you trust and knows you and your guitars is probably your biggest problem -
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  #21  
Old 10-17-2017, 02:24 AM
HNS HNS is offline
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Default Guitars prone to Neck resets and bellied up bridges

Thank you all ..... I’ll look into older Taylor if I get a chance in my neck of the woods.
Tadol. You nailed it . I have my guitars well humidified. I just have to find a quick solution to floor heating, I can’t leave the guitars on the floor anymore.
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Last edited by HNS; 10-17-2017 at 04:37 AM.
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  #22  
Old 10-17-2017, 08:18 AM
Truckjohn Truckjohn is offline
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Remember its still the same universe...

It's not "If" it will need maintenance - it's "When"....

A guitar is going to need some maintenance between 20 and 40 years old. If it's a mid 90's - you are already walking into that window....

Also - a 1990's Taylor doesn't have the NT neck - that means a reset will run you $400+ vs $75 for shims....
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  #23  
Old 10-17-2017, 10:28 AM
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Remember its still the same universe...

It's not "If" it will need maintenance - it's "When"....

A guitar is going to need some maintenance between 20 and 40 years old. If it's a mid 90's - you are already walking into that window....

Also - a 1990's Taylor doesn't have the NT neck - that means a reset will run you $400+ vs $75 for shims....
Good point.
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  #24  
Old 10-17-2017, 11:55 AM
Rodger Knox Rodger Knox is offline
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It's not "If" it will need maintenance - it's "When"....
That's not necessarily true for all guitars, there are a few outliers. One factor that hasn't been mentioned is the variability of wood properties. Some guitars are made with wood that has sufficient resistance to creep so that they never need a neck reset. Why don't the higher quality guitars use that wood exclusively? There's no way to tell by looking or nondestructive testing.
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  #25  
Old 10-17-2017, 12:05 PM
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Why don't the higher quality guitars use that wood exclusively? There's no way to tell by looking or nondestructive testing.
That's the whole point. My idea was to find a model to predict wood creeping. I was mistaken, it can't be done just by looking at the guitar or piece of wood.

If you look at ebay or reverb, you'll find many guitars that seem to have been untouched over 50-60 years. Unfortunately, as you implied, they're not too many.
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  #26  
Old 10-17-2017, 01:17 PM
John Arnold John Arnold is offline
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that means a reset will run you $400+ vs $75 for shims....
For a butted bolt-on neck? How much is a dovetail reset in your neighborhood?
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  #27  
Old 10-17-2017, 01:51 PM
Rodger Knox Rodger Knox is offline
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That's the whole point. My idea was to find a model to predict wood creeping. I was mistaken, it can't be done just by looking at the guitar or piece of wood.

If you look at ebay or reverb, you'll find many guitars that seem to have been untouched over 50-60 years. Unfortunately, as you implied, they're not too many.
There is the rule of thumb that the creep is 3 times the initial deflection, so a bridge that rotates 2° from string tension will ultimately rotate 6°. That's about as far as you can go without needing a reset. So a guitar that rotates less is less likely to need a reset, but it's also less likely to sound great.
This only helps your decision if the rotation is more than 2° from string tension, that indicates it's very lightly built and has a higher probability of needing a reset. (and also a higher probability of sounding great).
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  #28  
Old 10-17-2017, 01:56 PM
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Originally Posted by Rodger Knox View Post
There is the rule of thumb that the creep is 3 times the initial deflection, so a bridge that rotates 2° from string tension will ultimately rotate 6°. That's about as far as you can go without needing a reset. So a guitar that rotates less is less likely to need a reset, but it's also less likely to sound great.
This only helps your decision if the rotation is more than 2° from string tension, that indicates it's very lightly built and has a higher probability of needing a reset. (and also a higher probability of sounding great).
Thank you Rodger .... this is good to keep in mind.
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  #29  
Old 10-17-2017, 03:18 PM
charles Tauber charles Tauber is offline
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Originally Posted by Rodger Knox View Post
There is the rule of thumb that the creep is 3 times the initial deflection, so a bridge that rotates 2° from string tension will ultimately rotate 6°. That's about as far as you can go without needing a reset. So a guitar that rotates less is less likely to need a reset, but it's also less likely to sound great.
The rule of thumb applies to wood, or "materials" in general? A materials science professor I once had did a wonderful demonstration of cold creep. He took a length of solder and coiled it around his finger and then suspended from a stand the coil by one end. By the end of the class, the solder had uncoiled the height of the stand until the solder rested on the table on which the support rested. Way more than 3 times its initial deflection.

I'm not certain that bridge rotation is any indicator of the need for a neck reset. Rotation of the bridge involves areas of the top before and after the bridge. Neck resets involve the entire upper bout rotating "into" the soundhole. One relates to the structure of the top, mostly, the other the body.

I have a 30+ year old guitar that is in need of a neck reset. It still has about the same amount of bridge rotation as it did when new. It's one of the best sounding guitars I've ever made (i.e. the top isn't over-built). The lower bout of the top has been largely stable, but the upper bout of the guitar - back, linings, bracing, "U" shaped neck block and upper bout of the top - has deformed, taking the neck with it.
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  #30  
Old 10-17-2017, 04:26 PM
Rodger Knox Rodger Knox is offline
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Originally Posted by charles Tauber View Post
The rule of thumb applies to wood, or "materials" in general? A materials science professor I once had did a wonderful demonstration of cold creep. He took a length of solder and coiled it around his finger and then suspended from a stand the coil by one end. By the end of the class, the solder had uncoiled the height of the stand until the solder rested on the table on which the support rested. Way more than 3 times its initial deflection.

I'm not certain that bridge rotation is any indicator of the need for a neck reset. Rotation of the bridge involves areas of the top before and after the bridge. Neck resets involve the entire upper bout rotating "into" the soundhole. One relates to the structure of the top, mostly, the other the body.

I have a 30+ year old guitar that is in need of a neck reset. It still has about the same amount of bridge rotation as it did when new. It's one of the best sounding guitars I've ever made (i.e. the top isn't over-built). The lower bout of the top has been largely stable, but the upper bout of the guitar - back, linings, bracing, "U" shaped neck block and upper bout of the top - has deformed, taking the neck with it.
That rule of thumb is for wood, other materials can be quite different.

I agree that bridge rotation probably isn't a good indicator, but can you think of anything that can be measured easily that would be better?

I've been interested in this for a while, I have one of those 60+year old guitar that's never had a reset and still doesn't need one. It does have a significant belly behind the bridge, but the action has not risen significantly in 40 years(I've had it over 50 years). I do have it strung with Extra Lights (0.10s), which may make some difference.
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