Bunya Braces

[Steve.Toscano]

Hey guys.
The misses bought me a heap of woods for the next build (steel string dready).
Anyway, the brace stock is bunya (top is sitka).
I've never built with bunya braces before. Any tips or tricks to working with bunya braces?
Should i aim for the same sizes and bracing pattern that works for me when i use spruce braces?

The grain in the these pieces seems to be much much wider then spruce, would this be a problem?

Cheers

[Steve.Toscano]

Note: i use an X brace pattern that I have modified slightly.

[Tod Gilding]

You may not get an answer to that one Felix

I find that Bunya properties can be all over the shop.

[Trevor Gore]

Anyway, the brace stock is bunya...

Should make good kindling...

[auscab]

Your misses buys you wood

Lucky you

At a recent tool sale a friend watched a lady buy her husband a no 1 Stanley for a present, more

As for what Trevor and Tod are saying of Bunya , is it's stiffness the problem for braces ?

[nnickusa]

Iused Bunya on my first, as it was part of the "kit' my wife gave me for X-mas a couple back. Knowing nothing, and not having any spruce of any flavour at hand, I built with it, and had a BUnya top, too.

It sounds fine, but my ear is about as finely tuned as a....well, let's just say it's made of tin....

Other people who really should know better than to encourage me have been approving....

[Trevor Gore]

As for what Trevor and Tod are saying of Bunya , is it's stiffness the problem for braces ?

The stuff I've come across is about half the stiffness of good spruce and denser, so not much, really, to recommend it.

If you build off standard plans, you're almost certain to get an over-built guitar if you use good materials. If you use "average" materials, you will still likely get an overbuilt guitar. If you use poor materials you can get a guitar top that is not too stiff, but will be rather heavy, so won't have the loudness of a well designed guitar. This not only goes to show that it is relatively easy to get an outcome better than the factories achieve, but also shows how much performance is left on the work bench when good materials aren't used to their potential.

[Steve.Toscano]

I cut out a length about 10mm square x 400mm long. Compared it to some German spruce i had laying about that is the same size. Weight and stiffness *feel* identical.
The bunya is in nice big lengths. Perfectly quartersawn. I can always use it for end blocks and back bracing i suppose.

[Steve.Toscano]

Your misses buys you wood

You could say we have a wood exchange program going on.

[Trevor Gore]

Compared it to some German spruce i had laying about that is the same size. Weight and stiffness *feel* identical.

Nothing like measuring it for real, then you know what you have. You may even have some from the legendary tree that Bootle found. Or you may have some rather nasty German spruce...

For the record, decent Sitka measures up with an Elong of ~13 GPa and a density of ~450Kg/m^3.

On the other hand, the Bunya I've measured comes out at 4-6 GPa, density ~500Kg/m^3.

[Steve.Toscano]

Thanks Trevor.
How does one measure this?

Sorry for the noob questions.

[Trevor Gore]

There's two main ways: static testing, which usually comprises a three point bend test and dynamic testing where you measure the vibrational frequency of a rectangular section piece of wood and then figure out the Young's modulus. Both give the same results to a very close tolerance. Once you get used to it, the dynamic method is faster and is what I use most of the time. You've then got to figure out how best to use the results. There's quite a bit to know about, so I'd recommend reading up on it.