Starting WRC\Panama Rosewood Falcate Classical guitar.

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johnparchem
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Starting WRC\Panama Rosewood Falcate Classical guitar.

Post by johnparchem » Mon Nov 28, 2016 12:03 pm

This will be my third contemporary falcate braced classical using really good sounding Panama Rosewood from LMI. The tap tone sounds great and rings for 7 or so seconds. The taps ring so long I could have read the tap tones used for thicknessing right from the real time spectrum graph. I have found this wood surprising as it has an EL of 22.5 GPa with a density of 930 Kg/m^3. It is a bit outside of what I see for Dalbergia tucurensis in the wood database. Especially the El. The other thing is this wood has a strong smell more like Cocobolo or BRW. Again according to the wood database http://www.wood-database.com/yucatan-rosewood/ Panama Rosewood is not suppose to have much of a smell. This project is a bit educational so that I can hear the difference between a falcate Spruce and Cedar classical guitar.

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The WRC is a nice well quartered set that I have had for awhile.

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Last edited by johnparchem on Mon Nov 28, 2016 12:21 pm, edited 1 time in total.

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kiwigeo
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Re: Starting WRC\Panama Rosewood Falcate Classical guitar.

Post by kiwigeo » Mon Nov 28, 2016 12:18 pm

I look at that cross grain Youngs Modulus value for the WRC and straight away I have a vision of wet cardboard in my head.....but that's just me. Looking forward to seeing the final results on this build John.
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johnparchem
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Re: Starting WRC\Panama Rosewood Falcate Classical guitar.

Post by johnparchem » Mon Nov 28, 2016 12:55 pm

kiwigeo wrote:I look at that cross grain Youngs Modulus value for the WRC and straight away I have a vision of wet cardboard in my head.....but that's just me. Looking forward to seeing the final results on this build John.
We will see, the plate does sound musical when tapped. The tap tone sustains about five seconds or so. So at least long grain sound good.

Dave M
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Re: Starting WRC\Panama Rosewood Falcate Classical guitar.

Post by Dave M » Tue Nov 29, 2016 2:48 am

I would have expected the required top thickness to be a bit bigger but I guess the spreadsheet never lies!

I was looking again at the really useful article by Alan Carruth and Jim Blilie in GAL no 125. Demonstrates completely clearly the overlap in stiffness of the woods we use for tops. With the exception of your WRC which is distinctly lower.

It really isn't the species it's the piece of wood in front of you that matters.
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johnparchem
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Re: Starting WRC\Panama Rosewood Falcate Classical guitar.

Post by johnparchem » Tue Nov 29, 2016 3:58 am

Thanks Dave,

The El of 8.2 GPa is what has the thickness a bit smaller than the average shown in the book. My 2.9 mm for a SS vs an average of 3.19 in the Book. This top has a high Elong vs the Book and a low but in range Ecross.

I went back and did a little bit of calculations. A top made with this wood would end up about 5% heavier than the average for WRC in the Book and about 10% heavier than the average Engelmann Spruce top. I will give this top a bit more thought.

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