Falcate bracing

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DarwinStrings
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Falcate bracing

Post by DarwinStrings » Thu Mar 21, 2013 7:10 pm

G'day Trevor, I am a bit curious about a few things.

You use 7mm and 9mm to achieve 170Hz and 180Hz respectively. I assume you don't expect them both to end up with a 2 degree bridge rotation so what sort of difference to you end up with?

Spruce will bend easily to the shape of the main falcates so why do you choose King Billy? I can understand the use of King Billy in the secondaries.

If I used spruce for my main falcates would I reduce their height and if so what sort of percentage would I reduce them by?

The extra braces that run around the sound hole I notice are bound in by the top layer of CF but do you feel the need for a bit of glue on the endgrain to long grain join as well?

I probably have a thousand or so more but will let you catch your breath first.

Jim
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Re: Falcate bracing

Post by Trevor Gore » Thu Mar 21, 2013 8:44 pm

DarwinStrings wrote:You use 7mm and 9mm to achieve 170Hz and 180Hz respectively.
No, I said the braces are typically between 7mm and 9mm high, and (elsewhere) I pitch the resonances of medium sized guitars at ~170Hz and small body guitars at ~180Hz. Big difference. The resonant frequencies you get depend a lot on the materials you use and the way you put them together, as well as the brace height and size of the guitar. For example, I nearly always use braces around 7mm high, but recommend that most people start with 9mm high to get to the same end point using the same materials. Why the difference? All I can say is that experience seems to count - it seems that I put them together better. That is all I can isolate it to.
DarwinStrings wrote:I assume you don't expect them both to end up with a 2 degree bridge rotation so what sort of difference to you end up with?
The two degrees bridge rotation is used as a guide to sizing the bracing (on SS guitars) because most of the stiffness is in the bracing and most of the mass is in the top panel. But, as I've said elsewhere, you see the bridge rotation but you hear the resonances, so regard the two degrees as a ball park to be in for a responsive guitar, which gives you a decent chance of homing in on your target resonances.
DarwinStrings wrote:Spruce will bend easily to the shape of the main falcates so why do you choose King Billy? I can understand the use of King Billy in the secondaries.
Depends on the spruce. I've had spruce that could not be bent for the primaries and spruce that will easily bend to the secondaries. I had quite a large stock of bracewood which could not be bent for primaries when I was developing falcate bracing, which is why I looked for alternatives, as I assumed all spruce would not bend. When I got in the next batch of spruce bracing stock (a couple of years later, and Sitka again), it would easily bend for secondaries.
DarwinStrings wrote:If I used spruce for my main falcates would I reduce their height and if so what sort of percentage would I reduce them by?
Spruce has ~ twice the Young's modulus of King Billy and for the same brace height gives me ~10Hz lift in main top resonance.
DarwinStrings wrote: The extra braces that run around the sound hole I notice are bound in by the top layer of CF but do you feel the need for a bit of glue on the endgrain to long grain join as well?
I work on the basis that anywhere wood touches wood, glue it.

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DarwinStrings
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Re: Falcate bracing

Post by DarwinStrings » Thu Mar 21, 2013 11:53 pm

Cheers for clearing that up for me Trevor. I must have missed a bit in the black book. I was getting that 7mm and 9mm bit from 11.2.5.5. "Shaping the braces" in the white one and couldn't see how you could get 2 deg for both on the guitar in the plans.

So now when I buy my braces I should ask for the bendy spruce not the other one.

Cool, that gives me something to guesstimate brace height with.

Those joints had me bothered and I naturally wanted to house the buggers.

Jim
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Re: Falcate bracing

Post by Trevor Gore » Fri Mar 22, 2013 12:55 am

DarwinStrings wrote:So now when I buy my braces I should ask for the bendy spruce not the other one.
:lol:
It was the really tight grained, bony stuff (lots of silica in it) that collapsed on the insides of the bends for me (fantastic for straight back braces, though), but it's difficult tell what it will do until you try to bend it. There's two silver ashes, too (if you ever get to messing with silver ash). One bends and one doesn't. The one that doesn't bend is slightly yellower and stronger smelling, but both are sold as silver ash (sometimes called northern and southern, I think, but I can never remember which is which).
DarwinStrings wrote:Those joints had me bothered and I naturally wanted to house the buggers.
With the glueline at the soundhole reinforcement, the joint with the soundboard, the butt joint and CF over both sides of the butt, there's probably enough...

I'm pleased to hear you're taking on the falcate, Jim. Are you using the body shape in the book or one of your own?

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Re: Falcate bracing

Post by DarwinStrings » Fri Mar 22, 2013 12:01 pm

The shape I am using is a parlour Trevor. Taken from a 1905 Washburn with a little more meat added below the extremity of the lower bout width, a little thicker in the waist, the soundhole moved a bit towards the neck and a bit more depth to the body. Also 14 fret to body.

I feel better about that join now and so will not add skewed screws through the falcates into the end grain of those sound hole braces.

Jim
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Re: Falcate bracing

Post by Trevor Gore » Fri Mar 22, 2013 1:47 pm

DarwinStrings wrote:I feel better about that join now and so will not add skewed screws through the falcates into the end grain of those sound hole braces.
:lol:

Young Tom built a falcate parlour. I'm not sure exactly what he did, but it sounded really good even with me playing it. I would expect him to have stuck pretty close to the principles in the book.

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Re: Falcate bracing

Post by DarwinStrings » Fri Mar 22, 2013 2:31 pm

Is that one he made as a student of Alan Lloyd? Am not sure he needs much luck to go along with the skill he has.

I am trying to stick close to the book but as I had started this one (the tailpiece one with the failed top, now on the back burner) before I bought the book there are a few differences like the back was thinned by ear, not maths and is not domed but more trad. I will see how it goes then there is always the next one. This one is 330mm across the lower bout.

Jim
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Re: Falcate bracing

Post by kiwigeo » Fri Mar 22, 2013 2:34 pm

Jim,

I tried spruce for my laminated braces and found it a pain in the arse to bend. Occasionally you'll find a piece of spruce that will do what you want it to do but generally not. King Billy Pine bends like butter and its worth the effort trying to find the stuff.
Martin

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Re: Falcate bracing

Post by jeffhigh » Fri Mar 22, 2013 3:03 pm

I'm on my fourth falcate build, all using sitka, never found it a problem to bend.

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Re: Falcate bracing

Post by kiwigeo » Fri Mar 22, 2013 4:00 pm

jeffhigh wrote:I'm on my fourth falcate build, all using sitka, never found it a problem to bend.
Well you must have more patience or better sitka bracing stock...or both.
Martin

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Re: Falcate bracing

Post by DarwinStrings » Fri Mar 22, 2013 6:03 pm

Thanks Martin and Jeff. I tried to get some King Billy but it seems some Geologist from South Australia has already bought up all knows remaining stock of it.

I have a set of braces all ready to go out of Sitka, the spruce deity was on my side this time.

Jim

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Re: Falcate bracing

Post by kiwigeo » Fri Mar 22, 2013 8:01 pm

DarwinStrings wrote:Thanks Martin and Jeff. I tried to get some King Billy but it seems some Geologist from South Australia has already bought up all knows remaining stock of it.

I have a set of braces all ready to go out of Sitka, the spruce deity was on my side this time.

Jim

To seek perfection is human, to achieve it is not.
I spent a day trying to find some KBP. Walked into Otto's here in Adelaide and asked them if they had any and they remarked that I should try Tasmania....sums up how helpful and professional that place is. Popped into Carbatech on the way home and found a huge hunk of the stuff propped against one of their walls.
Martin

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Re: Falcate bracing

Post by Trevor Gore » Fri Mar 22, 2013 8:31 pm

DarwinStrings wrote:Is that one he made as a student of Alan Lloyd?
I think the parlour was his 4th guitar, the clone of mine his third (both of which he built in his own shop, iirc.) and I think the previous two were with Alan. He may have borrowed one of Alan's moulds for the parlour though, as Alan built a few. The pics were taken in Alan's music room.

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Re: Falcate bracing

Post by Barry Daniels » Tue Mar 26, 2013 12:24 am

jeffhigh wrote:I'm on my fourth falcate build, all using sitka, never found it a problem to bend.
Jeff, since you have some experience with sitka, can I ask you what height braces you used and what your main top resonances turned out to be? I want to try an OM for my first falcate using sitka and would like to target 170 Hz.

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Re: Falcate bracing

Post by jeffhigh » Tue Mar 26, 2013 6:56 am

7mm should be fine for a 170kz OM

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Re: Falcate bracing

Post by Barry Daniels » Tue Mar 26, 2013 11:11 pm

Thanks Jeff!

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Re: Falcate bracing

Post by n~dl » Fri Apr 05, 2013 2:53 am

While the subject is floating about here, can any of you recommend some spruce alternatives, for those of us outside Australia, who might be able to find king william anywhere? I'm pretty patient at the bending iron (rather enjoy it, actually), but of course if I can get anything done faster...!
Some kind of cypress or cedar, possibly? Suppose I'll just have to experiment.
-Nate L

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Trevor Gore
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Re: Falcate bracing

Post by Trevor Gore » Fri Apr 05, 2013 9:38 am

An alternative to spruce that won't bend is spruce that will :shock: , though it's very hard to tell the difference until you try it.

A possible alternative to try is Alaskan yellow cedar. I'm sure, by now, a variety of other species will have been tried and maybe we'll hear about them...

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Re: Falcate bracing

Post by n~dl » Fri Apr 05, 2013 1:43 pm

Haha, yeah, I thought that might be the case. I've been thinking of Port Orford Cedar, actually, which, like Alaskan Yellow, is also a cypress. It's pretty light, stiff, stable. I've seen it offered in a few places as back/sides sets, so I figure it's gotta bend with ~some~ effort?

But either way, it smells real nice :P
-Nate L

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Re: Falcate bracing

Post by jeffhigh » Fri Apr 05, 2013 3:45 pm

Alaskan Yellow bends easily for flamenco sides in my experience

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Re: Falcate bracing

Post by Steve.Toscano » Tue Oct 13, 2015 10:47 pm

Sorry to dig up an old thread.
What about WRC for falcate braces? I recently salvaged some from an old outdoor table. Perfectly quartered.
Haven't tried bending it yet.

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Trevor Gore
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Re: Falcate bracing

Post by Trevor Gore » Wed Oct 14, 2015 12:55 pm

WRC tends to bend like a carrot. I've never tried really hard to get it to bend, but I wouldn't be holding my breath. If you can't find any bendable spruce, maybe try macrocarpa. Never tried to bend it myself, but at least it's not that hard to get hold of.

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Re: Falcate bracing

Post by RobDyball » Thu Oct 15, 2015 5:04 pm

Macro is probably the easiest thing I've bent so far, couldn't get it to break
R

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