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PostPosted: Wed Sep 01, 2010 8:15 pm 
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Koa
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Hi everyone,

I finished carving my braces late last week, and yesterday I glues the soundboard to the neck, and today the tailblock -
Tomorrow I will touch up the sides on my pipe bender, cut some more linings and glue up the sides, later this week.

Any comments on my bracing ? This is my first -

I noticed the bridge pad, which I forgot to cut to shape, adds a lot of stiffness to the board. I wish I had made it thinner. It is about 1/16". I followed the Natelson plans in the Cumpiano book. The V at the bottom, I feathered the ends in the middle, due to some comments on this board on another post, from Fillipo and Waddy -

Please let me know your thoughts - Once I put sides and back on this box, I will continue to brace and button up my Cedar and Walnut #2 guitar... so I can put your comments to good use, likewise it is not too late to make changes on this sound board either, as the sides aren't glued in yet.



Thanks in advance !!


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PostPosted: Wed Sep 01, 2010 9:35 pm 
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This is really hard, as I haven't heard what it sounds like, but my inclination would be to taper the end of the fans below the bridge more gently, starting a couple of inches below the bridge, and get rid of that quick angle. I'm guessing you are a bit overbraced with that bridge patch, but that's just an opinion based on looking and not listening to it and feeling it. I'm less concerned about the quick angle above the bridge, as a little more stiffness is good there. Did you taper your top at the edges? How thick is the top? 1/16 th is only about a mm and a half, not too terribly thick. I would like to see the bridge patch tapered to the top at the edges, even if it's an afterthought. Is it wider than the bridge by a bit? How wide are those fans? Knowing that might help a little. Have you tapped and listened to the sound you are getting? Is it relatively even all over the lower bout? Is it a nice low tone with some sustain?

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PostPosted: Wed Sep 01, 2010 9:52 pm 
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Thanks Waddy -

The bridge patch is 1/16" thick - the soundboard I believe is .7 to .8 - Lutz spuce.
The patch is stiffening it up some - I will try to sand it down a lot more and see if I can get it looser that way.

My fan braces are each a little under a 1/4" wide and three center ones are about 1/4" tall (Cumpiano stated the 3 center ones to be full height of the blank, 1/4") and the exterior ones are 1/8" tall - all sizes approximate -

I can break that angle behind the bridge a little bit....

tapping it all around I am getting a tone like the 6th string on a guitar - note = E

any thing else ?

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PostPosted: Thu Sep 02, 2010 9:22 am 
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Hmmm! The top is certainly thin enough at, I hope, .07 - .08". One question, how is your top stiffness, cross grain? I have found Lutz, or at least the stuff I've dealt with, so far, to be a bit floppier across the grain, but very stiff longitudinally. The Euro seems to be much stiffer cross grain. Not a bad thing, but it does make a bit of a difference in how I treat the tops. I tend to leave the Lutz a little thicker in the wings. The bridge patch will help with that. With your fans at 6mm wide, I think you could bring them down in the center just a bit, if the top seems stiff. I'm less concerned about the note you hear than whether or not it is very even all over the lower bout, but that sounds like a pretty good place to be, generally. The top resonance is going up when you glue it to the sides. Personally, I'd probably take a mm or two off of the center fans at 6 mm + wide. Mine are about as tall as yours in the center, but they are only 3+ mm wide with no bridge patch. Torres braces, for a reference point, are 7 mm wide and about 3 mm high, all the way across the board. That tells me something. How about you? What size is this guitar in the lower bout? Width at wides point? I've read Cumpiano a couple of times, but I can't remember the dimensions of his guitar.

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PostPosted: Thu Sep 02, 2010 9:51 am 
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The wings at the lower bout are a little floppy - but I am not too concerned with the thickness. I know I took off a little more than I wanted on the soundboard - and I still have final sanding to get rid of a couple little nicks here and there.
My fan widths are right around 5 mm - 4.7 for the most narrow and 5.2 for the thickest - I will take a little more off the taller braces and sand the bridge pad down a bit.
My lower bout is 14 and 7/8" at the widest point.

correction on plate thickness - I just remeasured with my calpiers - it come out to about .08 at it's thinnest to .095 in some parts. My recollection was incorrect.

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PostPosted: Thu Sep 02, 2010 10:33 am 
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Honestly, I don't really like how it looks, but my first brace carving job was worse. But how it looks doesn't make the sound. I would rather advise not to work on them anymore between bridge and soundhole since your front tapers are too aggressive already (but wait, how deep is your solera?) In any case you could refine the cutoff bars. As a rule I want to see gentle height transitions, nothing abrupt as seen in some over-scalloped X braces.

The pad is sort of neutral, it does add stiffness but weight too. Transverse braces are similar. If you'd hunt the main resonances before and after adding a patch you'd see they don't change much if at all. Although they do obviously move after each correction on the fan braces! In other words, a bridge patch does not compensate for a too thin top / weak fan.

If you want to get inspiration from some truly beautiful brace works, check out some of Jeff Elliot.

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Last edited by Alexandru Marian on Thu Sep 02, 2010 10:39 am, edited 1 time in total.

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PostPosted: Thu Sep 02, 2010 10:38 am 
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That's actually much better on the thickness, depending on where the thin and thick parts are. Your guitar is a pretty big body. I'd not take too much off those center braces, yet, the width is not as much as I thought. I would soften the hump where it dives, for better transition of stiffness to the tail. What does your bridge look like? You'll get some cross grain stiffness there, in addition to the patch. My thought on the patch is to just soften the edges down, not to thin the whole thing. How thick does he recommend for a bridge patch? I don't use one, so I don't have much experience there.

Alex posted before I did. I agree with what he said, that's why I said not to do anything above the bridge patch. He's right on the softer transitions though.

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PostPosted: Thu Sep 02, 2010 10:58 am 
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Cumpiano suggest 1/16" for the bridge patch - but I think for the next one - I may make it thinner and smaller.

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PostPosted: Thu Sep 02, 2010 11:26 am 
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You just want to make sure it's a little bigger than the bridge, all around. Look at the Elliott one, though he doesn't bevel his, I see. I would, but that's me.

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PostPosted: Thu Sep 02, 2010 2:55 pm 
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I have to say that it does look a bit overbraced to me, but only you with it in your hand can really judge.

However, I'm a Torres purist, and use just 7mm x 3mm fans on a 2.2mm top, so anything with a bridgeplate looks wrong.

I'd most certainly graduate the profile of the fans though.

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PostPosted: Thu Sep 02, 2010 3:47 pm 
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Ok - I took your suggestions - and taper a little more and made the tapers more gradual - I will keep all this in mind for my next soundboard which I will be doing in a couple of weeks.

Thanks - more comments still welcome -


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PostPosted: Thu Sep 02, 2010 3:53 pm 
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On my next builds I am going to eliminate the bridge patch and see how that works out. I'm thinking it's not as necessary as I once thought it was. Actually i am doing that now but my current one is a double top. FWIW I tend to keep the three center braces full sized in front of the bridge.


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