Opinions about bubinga wood ?

[skap]

I would appreciate to hear any opinions about bubinga (African rosewood) wood in the flute making context. Specifically, the durability. Would it be less prone to cracks than blackwood or boxwood, does it warp, etc ? But also the influence on the tone.

[Terry McGee]

I've heard of the timber from local woodies, but have had no experience with it.

On a quick glance, it would appear a bit lighter than we'd like, and probably too dense to make it hard to "bulk up" with chemicals. Inserting it in our developing list, which starts at the absurd and progresses to the extremely effective....

Pine 0.4
Pear 0.65
Birch 0.67
Bubinga 0.89
Boxwood, 0.95

Water 1.0

Blackwood 1.27,
Mopane 1.3,
Gidgee 1.35
Delrin 1.356

On the stability issue, this might help:

Boxwood Shrinkage: Radial: 6.2%, Tangential: 9.8%, Volumetric: 15.8%, T/R Ratio: 1.6
Bubinga Shrinkage: Radial: 6.0%, Tangential: 8.2%, Volumetric: 13.9%, T/R Ratio: 1.4
African Blackwood: Radial: 2.9%, Tangential: 4.8%, Volumetric: 7.7%, T/R Ratio: 1.7
Gidgee Shrinkage: Radial: 4.0%, Tangential: 5.1%, Volumetric: 9.2%, T/R Ratio: 1.3
Mopane Shrinkage: Radial: 4.0%, Tangential: 5.2%, Volumetric: 9.3%, T/R Ratio: 1.3
I'm imagining that Delrin doesn't exhibit any significant movement with humidity!

(T/R Ratio is the ratio of the Tangential and Radial rates, and can be seen as a measure of how uniform the shrinkage will be. A higher ratio when combined with high Volumetric shrinkage will encourage ovalling.)

Bubinga's shrinkage rates look more like boxwoods than those of the heavier woods we gravitate towards. Again, doing something to prevent the moisture getting into the wood (like a really impervious inner coating) would help mitigate against player-induced movement.

Having a metal lined sections would probably be a bit dangerous, for the same reasons we see in old boxwood flutes. Really old boxwood flutes (before tuning slides) generally survive well, but later ones with slides generally didn't. I'd imagine that those high shrinkage rates could contribute to cracking in long cold or dry spells or when the flute moves to New Mexico!

[Geoffrey Ellis]

I've used a lot of bubinga over the years (don't use it anymore since CITIES) but never for a jointed, conical bore flute. I've used it for things like xiao, shakuhachi, and other one-piece flutes. It's nice for some applications, but I don't like reaming it. It's quite hard but not oily, so it fights the reamer more than things like blackwood, cocobolo, bocote, etc... It's a lovely wood, especially if you get some with a bit of figure in it, but I don't think it would be a great choice for the sorts of flutes being discussed on this forum. Terry's right about it absorptive qualities as well--I've tried resin stabilizing it and it just doesn't gain any significant weight.

[flutefry]

I had a recorder in bubinga and I noticed that the grain raised in the windway, so it was no longer flat and smooth, and the lip wasn't sharp. Pretty as can be, but functionally, didn't work that well in my opinion.

[skap]

Thank you all for your comprehensive answers. Theory, application, and the end user experience seem to converge here.