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trying something a little different
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12694		 Page 1 of 1
Author:  KenH [ Tue Jul 03, 2007 3:26 pm ]
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Just wondered if any of you have tried this?


I am working on #13, which is going to be a sycamore body with a western red cedar top. The back I braced with a cross brace pattern.


The top is what I am doing different, and am not too sure how it is going to turn out, but so far looks promising:


I thicknessed the top to .150, then braced it using thin parabolic braces all around. After the top was installed, I sanded the top so that it remained at .150 in the center, and progressively got thinner toward the edges... down to about .40


I have the box completed, and the tap sounds good on it, but I'm not sure what tone or range of tones I will experience with this. This guitar will have a load of MOP, PAUA and inlays on it, so it will be a while before I get to hear it.


This is my first WRC top, and my first attempt at parabolic bracing. It is also a first for trying this thicknessing scheme. Anyboddy else tried this?


 
Author:  Jim Watts [ Tue Jul 03, 2007 4:29 pm ]
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As you know there's a lot of unknowns here. such as body size top stiffness, etc..
I've only used wrc a few times and mostly build with euro and am also liking Shanes wonderful Lutz spruce.
My typical top would be somewhere around .110 -.115 and taper out to about .100 - .095 at the edges and I use tall thinish braces. 15-1/2" lowere bout. So..., .150 sound awfully thick to me, even for WRC.
Maybe someone who builds with WRC a lot will chime in.
Author:  Kevin Gallagher [ Tue Jul 03, 2007 4:34 pm ]
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    The tapering of the top to a significantly thinner dimension around the
perimeter than in the center is a common practice for most builders. I don;t
go quite as thin as .040", but do thin them at their perimeter.

     There is a fine line between thin enough and too thin and you need to be
careful not to cross it or you will jeopardize both tone and integrity. Mass is
essential to vibration which, of course, is what creates tone and volume. Too
much mass is not good, but too little is not good either.

Regards,
Kevin Gallagher/Omega Guitars
Author:  Steve Saville [ Tue Jul 03, 2007 4:42 pm ]
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It sounds to me like it is too thick in the middle and too thin at the edges.
By too thick I think it will be too heavy and too rigid to sound good.
By too thin I mean that it will be structurally unsound and not support structurally or be strong enough to produce/transmit good sound.
That is my opinion, based on not much knowledge. If you continue with that top, and I would not, it will be real interesting to see/hear how it turns out.
It is people like you who are courageous enough to try stuff that is not recommended that push boundaries and make wonderful discoveries. I wish you luck and learning with this great effort.
      
Author:  KenH [ Tue Jul 03, 2007 5:21 pm ]
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By the way, this is a dreadnaught guitar. I left the upper bout fairly thick (~.120 at the edges), but still the area around the sound hole being the thickest part of the top.  From the soundhole and spreading outward and downward towards the tail and lower bout edges I sanded it progressively thinner.


I have no idea how it will turn out either. The WRC seems MUCH stiffer than any of the spruces I have used, so I dont think it will be a strength problem. I have placed the box in front of a speaker playing rock music and the whole box has some nice vibrations to it. As far as the thickness around the sound hole, it should be no thicker than Brock's double ply spruce that he does for placing binding around the sound hole. I may even place some binding around the sound hole also on this one since it is thick enough to support it.


My theory on trying this is similar to a speaker cone and they way they are built. Most of them flex at the outer edges and are thicker and heavier near the magnet. This guitar will carry a pinless bridge made out of snakewood also, and the bridge is somewhat heavier than most ebony or rosewood bridges. Again, my thinking is that every note played on the guitar will find a different point of vibration on the top because of the variable thicknesses.


I have several ideas on building that I will be trying out soon.. heck, thats what being a luthier is all about anyway??
Author:  crazymanmichael [ Tue Jul 03, 2007 10:57 pm ]
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i tend to agree with those who feel the dimensions are too extreme. but as you have the box complete not much could be done about it even if you did want to change it without major surgery.

but i can't understand why you would want too expend a lot of time and money on lavish appointments on what is essentially a rather radical experimental prototype. i always build a prototype(s) of any new shape i haven't built before, or when trying new ideas on existing models. these are done in basic grade woods, e.g., allied's "opportunity" grade eir, with tops selected solely for stiffness with no regard for cosmetics. basic binding and rosette, generic rather than proprietary bridge and no logo/lable. after i have completed the evaluation and critique phase, i use them as shop beaters or give them away, donate them, etc.
Author:  Don Williams [ Tue Jul 03, 2007 11:50 pm ]
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I know of folks who leave cedar tops that thick, so it doesn't seem too awful extreme to me in that direction. It's the .040" that scares me!
What I'm curious about is why you're going to put all that pearl and inlay and snakewood into a guitar that is by your own definition - experimental.
I just posted on another thread about the "3 F's" of design - "Form Follows Function". Maybe you would want to consider what Michael suggests and simplify to get the sound the way you want it and then build the more lavish instrument. <ducking>
Author:  KenH [ Wed Jul 04, 2007 12:43 am ]
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I may actually sneak a way to play the guitar a little before I get all of the trim on it... it will be a bolt on neck, so I can use another neck from another guitar and I also put a bridge plate in it even though I didnt plan on using pins, so I could possibly bolt on temporarily a bridge to try it out. I always leave myself some wiggle room.
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