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  #1  
Old 03-23-2017, 05:33 AM
hat hat is offline
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Default 12 string build - tips and advice?

I'm thinking about a 12 string guitar project. Any advice on building techniques for the extra tension? I think perhaps laminated sides would be a plus, other thoughts?
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Old 03-23-2017, 05:43 AM
Silly Moustache Silly Moustache is offline
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If I were you, I'd look at the Martin D12-20 /35 designs. 12 fret, short scale, wide neck, big but resonant dread style body. I use mediums (EJ37) on mine but tune it down one tone (D)

Oh, and add in a truss rod !

Like this :

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Old 03-24-2017, 12:32 AM
mb propsom mb propsom is offline
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I laminate the sides on all of my 12 strings. A good practice to counteract potential side deformation over time. Also, I'd recommend you make the lower tone bars about 30% higher than those of a six strings.

Personally, I would avoid bracing the guitar like a Martin. i've found most Martin 12's too "jangly" for my liking.

I do agree with Silly Moustache that stringing a 12 with mediums and tuning a full step lower is the way to go. Gives any 12 a richer sound.
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Old 03-24-2017, 12:34 AM
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And by the way, Tom. If you read this post Friday before noon PDT, go to the Mighty Fine Guitars website and tune into Stevie Coyle's live webcast. He'll be featuring a couple of 12 strings, including one of mine and one of my mentor's the late Bozo Podunavac.
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Old 03-24-2017, 09:18 AM
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Quote:
Originally Posted by mb propsom View Post
Personally, I would avoid bracing the guitar like a Martin. i've found most Martin 12's too "jangly" for my liking.
Ok,I'll bite. How do you configure the bracing, if not like Martin does? I was considering 3 tone bars rather than two, but taking them pretty low.
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Old 03-24-2017, 10:38 AM
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I'd think some reinforcement plates around the soundhole. The Chinese Guilds seem to be thicker in those spots. This might be part of an attempt to keep the end of the neck from diving into and collapsing the soundhole.
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Old 03-24-2017, 11:35 PM
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Quote:
Originally Posted by hat View Post
Ok,I'll bite. How do you configure the bracing, if not like Martin does? I was considering 3 tone bars rather than two, but taking them pretty low.
First of all, I don't do scalloped bracing in either six or twelve string instruments, but rather taper them. And I set my lower tone bars with less of an angle than Martin and a lot of other guitar makers. I'll run through my photos in a day or two, and then figure out again how to post photos here. And in addition to the two lower tone bars I place another narrow, low strip between the second tone bar and the heel block on my twelves.
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Old 03-25-2017, 04:49 AM
LSemmens LSemmens is offline
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I will be following this build with extra vigilance, it may just convince me that I can forego some of my, many, other projects to attempt a build, myself.
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Old 03-25-2017, 04:19 PM
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Here's the only photo I could find of a 12 string top bracing. This is from my most recent 12, an EIR/POC 13 fret to the body Small Jumbo. While you're in my Photobucket feel free to check out other shots. I took this shot before gluing the small (5/16"w X 1/8"h) strip between the lowest tone bar and heel block.


http://s1198.photobucket.com/user/hi...7lfji.jpg.html
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Old 03-25-2017, 04:54 PM
Earl49 Earl49 is offline
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Quote:
Originally Posted by mb propsom View Post
.....This is from my most recent 12, an EIR/POC 13 fret to the body Small Jumbo.
POC = Port Orford Cedar, right? I won't tell you where my mind went first.....

Beautiful guitar, MB.
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Old 03-25-2017, 09:49 PM
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POC = Port Orford Cedar, right? I won't tell you where my mind went first.....

Beautiful guitar, MB.
Ha! That's right, Earl. It's a piece of -------cedar. Port Orford, as you figured.

This was a very special piece from a split billet I bought back in 1984 from Orcas Island Tonewood. I wasn't impressed at all with the wood's appearance--wide grain, and prominent latewood lines. But, when I resawed it and tapped the plates, they rang like a temple gong. Another example of "Don't judge a book by its----".

Although I'm very partial toward Sitka for 12's that Port Orford billet and subsequent tops that I've purchased from Vince Strauss have exhibited all the stiffness of the best Sitka that I've used, with a great fundamental and incredible sustain. But, I digress.
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Old 03-25-2017, 09:55 PM
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Quote:
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Ok,I'll bite. How do you configure the bracing, if not like Martin does? I was considering 3 tone bars rather than two, but taking them pretty low.
One thing you don't want to do, Tom, is make the tone bars low. Remember, you're dealing with increased torque on a twelve string bridge--around 100 lbs. more than on a six string. If you make your tone bars the same height as a six string, you're most likely going to get some radical bellying behind the bridge.

Like I had mentioned earlier, I make my two lower bars about 30% higher on a 12 than on a six.
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Old 03-26-2017, 05:10 AM
Brucebubs Brucebubs is offline
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I've never found a 12-string dreadnought I've liked but I've found several jumbo's that I do.
Size does matter.

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Old 03-27-2017, 09:47 AM
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Good thoughts. I noticed that the X on the top you posted a picture of seems pretty wide in the lower bout. I wonder if the lower legs of the X were brought in closer, wouldn't that aid in stabilizing the top? and perhaps also help free it up to vibrate, since the main braces would be a little closer to the top grain and line of string pull?
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Old 03-27-2017, 01:11 PM
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Quote:
Originally Posted by hat View Post
Good thoughts. I noticed that the X on the top you posted a picture of seems pretty wide in the lower bout. I wonder if the lower legs of the X were brought in closer, wouldn't that aid in stabilizing the top? and perhaps also help free it up to vibrate, since the main braces would be a little closer to the top grain and line of string pull?
Tom, I'm essentially using the same configuration since I built my first two twelve strings in 1979. This was when I was working for Bozo Podunavac, who was one of the acknowledged masters of 12 string guitar construction. I actually built four instruments for him under his name.

The oldest 12 of mine that I still have access to is one that I built in 1985, and it has no structural issues at all, so I believe that there wouldn't be any advantage to narrowing the x-brace angle. It might possibly diminish the bottom end of the instrument in that it could constrict what I believe is the instrument's greatest area of sound production.

For an example of this guitar's sound you might look at this video from Mighty Fine Guitars in which Brian Kolner plays a couple of Bozos and the Small Jumbo whose bracing pattern I shared with you. Although the sound production isn't optimum, you can get an idea of the overall tone and projection of the instruments. By the way, my guitar appears at about minute 20. Besides playing the guitars, Brian has some good input on neck set and other elements of the guitars.

https://www.facebook.com/MightyFineG...0/?pnref=story
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