Official Luthiers Forum! :: View topic - 12 string falcate braced Ziricote\spruce guitar with video

I built this as a commission, although I told the client that it was an experimental build as it was my first 12 string. I did use a lot of information from the Gore\Gilet books including the bracing pattern and bolt on\off neck design. The body is the Gore medium size steel string. I followed a tutorial from Craig Lawrence on the Australian\New Zealand Luthiers Forum for the 2 string per pin bridge. Richard Woods (Woodsy23 on also on anzlf) modified and ran an existing Finite Element (FE) model he had, for 12 strings load, both light and medium (EJ38s and EJ39s). He determined I would need to increase the height of the falcate braces to 10 mm for the EJ38s and 11 mm for the EJ39s. I ended up with 10.5 mm as I wanted to limit the monopole frequency of the top to keep it in the typical SS range. I ended with 175 Hz top frequency (that I may work to lower to 170 Hz). I have a spectrum analysis with strings at the bottom of this post. I did not measure the bridge rotation under load, but it looks good to my eyes.

The top is Lutz Spruce, back and sides Ziricote.
Bridge BRW, Fretboard EIR, Ebony bindings
rosette, Headstock, backstrap, end wedge, heel cap and side purfling are all Koa.
Finish: EM6000 on zpoxy fill for the body and CA fill and Royal Lac for the neck and head stock.

Author:	johnparchem [ Sun Aug 07, 2016 7:03 pm ]
Post subject:	12 string falcate braced Ziricote\spruce guitar with video
I built this as a commission, although I told the client that it was an experimental build as it was my first 12 string. I did use a lot of information from the Gore\Gilet books including the bracing pattern and bolt on\off neck design. The body is the Gore medium size steel string. I followed a tutorial from Craig Lawrence on the Australian\New Zealand Luthiers Forum for the 2 string per pin bridge. Richard Woods (Woodsy23 on also on anzlf) modified and ran an existing Finite Element (FE) model he had, for 12 strings load, both light and medium (EJ38s and EJ39s). He determined I would need to increase the height of the falcate braces to 10 mm for the EJ38s and 11 mm for the EJ39s. I ended up with 10.5 mm as I wanted to limit the monopole frequency of the top to keep it in the typical SS range. I ended with 175 Hz top frequency (that I may work to lower to 170 Hz). I have a spectrum analysis with strings at the bottom of this post. I did not measure the bridge rotation under load, but it looks good to my eyes. The top is Lutz Spruce, back and sides Ziricote. Bridge BRW, Fretboard EIR, Ebony bindings rosette, Headstock, backstrap, end wedge, heel cap and side purfling are all Koa. Finish: EM6000 on zpoxy fill for the body and CA fill and Royal Lac for the neck and head stock.

Author:	edstrummer [ Sun Aug 07, 2016 9:24 pm ]
Post subject:	Re: finished my 12 string falcate braced Ziricote\spruce gui
johnparchem wrote: I built this as a commission, although I told the client that it was an experimental build as it was my first 12 string. I did use a lot of information from the Gore\Gilet books including the bracing pattern and bolt on\off neck design. The body is the Gore medium size steel string. I followed a tutorial from Craig Lawrence on the Australian\New Zealand Luthiers Forum for the 2 string per pin bridge. Richard Woods (Woodsy23 on also on anzlf) modified and ran an existing Finite Element (FE) model he had, for 12 strings load, both light and medium (EJ38s and EJ39s). He determined I would need to increase the height of the falcate braces to 10 mm for the EJ38s and 11 mm for the EJ39s. I ended up with 10.5 mm as I wanted to limit the monopole frequency of the top to keep it in the typical SS range. I ended with 175 Hz top frequency (that I may work to lower to 170 Hz). I have a spectrum analysis with strings at the bottom of this post. I did not measure the bridge rotation under load, but it looks good to my eyes. The top is Lutz Spruce, back and sides Ziricote. Bridge BRW, Fretboard EIR, Ebony bindings rosette, Headstock, backstrap, end wedge, heel cap and side purfling are all Koa. Finish: EM6000 on zpoxy fill for the body and CA fill and Royal Lac for the neck and head stock. Looks amazing, John !!! Outstanding craftsmanship, as usual in your builds. Sent from my iPhone using Tapatalk

Author:	DanKirkland [ Sun Aug 07, 2016 10:34 pm ]
Post subject:	Re: finished my 12 string falcate braced Ziricote\spruce gui
Very cool, on the bracing I'm guessing you laminated carbon between two layers of spruce? Or am I seeing it wrong?

Author:	johnparchem [ Sun Aug 07, 2016 11:03 pm ]
Post subject:	Re: finished my 12 string falcate braced Ziricote\spruce gui
DanKirkland wrote: Very cool, on the bracing I'm guessing you laminated carbon between two layers of spruce? Or am I seeing it wrong? Thanks, The CF is under and over each spruce brace. So I laminate the top -> CF tow -> brace -> CF tow using epoxy.

Author:	MikeWaz [ Mon Aug 08, 2016 1:36 am ]
Post subject:	Re: finished my 12 string falcate braced Ziricote\spruce gui
Congrats on your 1st 12 string John! Sent from my iPad using Tapatalk

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12 string falcate braced Ziricote\spruce guitar with video https://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=48107	Page 1 of 1

Author:	johnparchem [ Mon Aug 08, 2016 2:32 pm ]
Post subject:	Re: finished my 12 string falcate braced Ziricote\spruce gui
Here is an you tube line with my guitar instructor Rob Hampton of http://www.heartwoodguitar.com/ playing my 12 string https://www.youtube.com/watch?v=UebH85F4PAU

Author:	bcombs510 [ Mon Aug 08, 2016 2:45 pm ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Really beautiful and such a great mix of woods! Any specific reason for the BRW bridge?

Author:	Colin North [ Mon Aug 08, 2016 3:34 pm ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Sounds just as good as it looks John.

Author:	Imbler [ Mon Aug 08, 2016 4:11 pm ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Sounds really nice John - congrats! Did you feel a touch nervous watching that pick flailing so close to your just finished top? He sounds like a great player, but I'd still be nervous without a pick guard

Author:	johnparchem [ Tue Aug 09, 2016 9:50 am ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Thanks all for the kind comments! Mike, I have some removable pick guards in the mail. I was not afraid to have Rob play the guitar he is pretty controlled with a pick. I have not tried to play the guitar with a pick.

Author:	johnparchem [ Wed Aug 10, 2016 11:58 am ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Thanks Brad, Mike and Colin, bcombs510 wrote: Really beautiful and such a great mix of woods! Any specific reason for the BRW bridge? I have a stack of BRW blanks, I like the look and it has good stiffness for its density. Given that this bridge has a layerof carbon fiber and there is another layer of CF under the bridge plate, I could of used a lighter wood like mahogany. In this case I did not mind a slightly heavier bridge as the top is stiffer than I build a 6 string and I wanted to keep the top resonance down.

Author:	EddieLee [ Wed Aug 10, 2016 5:43 pm ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
That sounds fantastic and the look is superb. Good Job.

Author:	bftobin [ Wed Aug 10, 2016 8:16 pm ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
I've never been a fan of twelve strings, but this sounds great !!! I heard lots of them over the years and this is REALLY nice. Brent

Author:	johnparchem [ Thu Aug 11, 2016 9:35 am ]
Post subject:	Re: 12 string falcate braced Ziricote\spruce guitar with vid
Thanks guys! Here is a link as the embedded player stopped working http://www.youtube.com/watch?v=UebH85F4PAU

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