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Lightly bracing SJ questions
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10102&t=14516		 Page 1 of 1
Author:  Terry Stowell [ Wed Nov 14, 2007 2:33 am ]
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I'm building an OLF SJ with a .100" carpathian spruce top, quilted sapelle B & S. My brother,the recipient, uses light strings. (I had to talk him UP to .010" or .011's!)  It's going to have an ebony fretboard, EIR binding, likely an ebony or EI Rosewood bridge.


I'm building per Michael Payne's plans for a reference since this is my first SJ from these plans. EXCEPT, I'm thinking of 1/4" "X" bracing


Anyone built SJ's using 1/4" "X" bracing? Any advice if I do? Bridge  and bridge plate recommendations? I have Maple (Big Leaf, IIRC) and rosewoods (BRW, EIRW)

Thanks
Author:  Hesh [ Wed Nov 14, 2007 2:48 am ]
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Terry I am building an OLF SJ, mahogany/ Lutz .100 right now with 1/4" bracing.  I just glued the X-brace joint last night.  The height of the X intersection is 1/2".

I know it's lightly braced but that is the plan here and I use triangular shaped braces for strength.

My bracing stock is Adi, very stiff and baked like I used to be back in high school and college.......  I will not be scalloping the braces.

I don't see a problem with this being to lightly braced and after the top is done I may even take the X intersection down further.

Disclaimer:  Although this is my 3rd SJ it is my first with bracing this light so what you read here is by no means to be construed as a recommendation.  I can't know how it will hold up over time.
Author:  grumpy [ Wed Nov 14, 2007 2:54 am ]
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If he's going to run such light strings, re-consider the body shape, and consider going to a smaller body. No matter how lightly you brace it, that is still a large surface to move with those wimpy strings.
Author:  Steve Saville [ Wed Nov 14, 2007 2:57 am ]
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[QUOTE=grumpy] If he's going to run such light strings, re-consider the body shape, and consider going to a smaller body. No matter how lightly you brace it, that is still a large surface to move with those wimpy strings.
[/QUOTE] Yep, that's what I was thinking.
Author:  Michael Dale Payne [ Wed Nov 14, 2007 3:14 am ]
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1/4" bracing on the SJ is fine. In fact I now use 1/4". You should have no problems. If you follow the bracing plans you will need to adjust the bridge plate accordingly and the length of the tone bars and such.
Author:  JJ Donohue [ Wed Nov 14, 2007 3:37 am ]
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I've built 2 OLF SJ's...both with 1/4" braces all around. I also use .011" lights and they have tone, volume and sustain out the wazoo...not at all wimpy.

The latest is my biggest sounding guitar ever IMO and confirmed by some well-respected local players. It is a Lutz / Cuban Mahogany. This one in particular has lots of volume and a refined full tone...much like it's namesake...<VBG>

Author:  JJ Donohue [ Wed Nov 14, 2007 3:48 am ]
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Todd...I have a 40 year old D-35 and agree with your comparison when playing with a flat pick. I've ued both lights and mediums and eventually settled on the mediums.

The above referenced 1/4" braced SJ actually outperforms the D-35 as a fingerstyle player when both are driven by lights. The SJ has much less mass as well as a lighter top. They are, of course, two different guitars and are intended for different styles of music. Having braced the SJ so lightly, I'd be a little reluctant to go to mediums.
Author:  Terry Stowell [ Wed Nov 14, 2007 8:56 am ]
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To my original question ~ Bridge plate wood recommendations? I forget what effect maple vs EIR has, etc..


Such subjective stuff....


 
Author:  Michael Dale Payne [ Thu Nov 15, 2007 2:09 am ]
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You are right The SJ has a top plate surface area of 59.75 sq inches. The OM has a top plate surface area of 59.33 sq inches

The SJ has a body volume of 1077.14 cubic inches and the OM has a body volume of 963.93 cubic inches

It is the difference in volume that really distinguishes the two.
Author:  JJ Donohue [ Thu Nov 15, 2007 3:58 am ]
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Terry...I use Padauk exclusively for my bridge plates. It is hard...and taps nicely. I have no basis of comparison with other woods on this style.

I await the preferences of others.
Author:  JJ Donohue [ Thu Nov 15, 2007 4:05 am ]
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Oh...forgot the bridge material.

On one (Carpathian/WF Bubinga) I used a BRW belly bridge.

On the other (Lutz/Cuban Mahogany) I used a snakewood straight (no belly) bridge.

I am pleased with the sound of both...it's just that the Lutz/Cuban seems to have a significantly more lively top and seems to have a bit more presence.
Author:  JJ Donohue [ Thu Nov 15, 2007 4:08 am ]
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Michael...Do you have any idea what the area and volume numbers are for a Dred?
Author:  Michael Dale Payne [ Thu Nov 15, 2007 4:16 am ]
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not off the top of my head but I will post at lunch
Author:  Michael Dale Payne [ Thu Nov 15, 2007 4:50 am ]
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Ok! I have to make a correction. I did not account for the heel to neck taper or brace and block areas on the volumes accounting for my neck block, tail block, and bracing the volumes are

Dread volume = 980 in3
SJ volume    = 930 in3
OM volume    = 878 in3

top surface area
Dread = 61.38 in2
SJ    = 59.75 in2
OM    = 59.33 in2
Author:  JJ Donohue [ Thu Nov 15, 2007 10:29 am ]
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Seems a lot closer to a Dred's volume than I ever imagined...only about 5% less.

That may explain the reason why the Lutz/Mahogany had a very similar big sound.

What impact does the shape itself have?

Author:  Terry Stowell [ Thu Nov 15, 2007 1:37 pm ]
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Okay. So I'm going out on a limb here. Just feel like changing the status quo here. I'm thinking of tapering the braces, and leaving them square at the tops. I was going to use parabolic. Now I'm thinking not.


 


What sayest thou?
Author:  JJ Donohue [ Thu Nov 15, 2007 2:30 pm ]
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Triangular at the top...scalloped...un-tucked lower x-brace arms for me.

One other significant difference I forgot to mention...I used Paul Woolson's solid liners which add a lot more stiffness to the rims.
Author:  Michael Dale Payne [ Thu Nov 15, 2007 2:49 pm ]
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squared top braces: added stress risers, undue weight or mass. I can think of no good reason to leave the braces with 90 deg edges.
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