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Main Forums => Technical Discussion => Topic started by: pakhan on December 09, 2009, 12:19:19 PM



Title: Koa tonewood Profile
Post by: pakhan on December 09, 2009, 12:19:19 PM
Hi Folks!

For your viewing pleasure, I have just published a profile on the acacia also known as Koa as part of my ongoing tonewood database. As always, improvements, corrections and additional information/ your own experiences are much appreciated- I'll update the profile citing you and linking back to you! If you have an experiences or data to share, I would be very grateful.

I can't link pics directly to here so do pop by to
http://guitarbench.com/index.php/2009/12/09/koa-tonewood-profile/

for the full Visual presentation. As always, I present the text portion of the article for your consideration- although I do highly recommend popping by to see the pics!

Warmest regards,
Terence
http://www.guitarbench.com

Acacia Koa | Tonewood Profile | "Koa"

All pictures - Click to enlarge!
Please email with any corrections/ additional info
We aim to keep each profile as complete as possible & your help is appreciated!

Quick Facts
Scientific name: Acacia Koa
Trade names: Koa
Janka: 1250
Uses: Tops, Veneer, Back and sides
RIYL: Walnut, Mahogany
Bling factor: Curl and colour variation is not uncommon
Availability: Uncommon
CITES status: Not listed. No restrictions

Note: (RIYL) Recommended If You Like

Natural History

Koa is endemic to the Hawaiian Islands attaining heights of 30 metres and 6 metres in diameter. It is found thriving in forest zones of 1002,300 metres on all 6 major Hawaiian Islands. As a nitrogen fixing species, it is able to thrive in very young volcanic soils.

Status

koa was used by ancient Hawaiians for a variety of uses from to build dugout canoes to surfboards. During the Hawaiian music craze of the 20's it's similarity in strength and weight to that of black walnut led it to be extensively logged for use in wood carving and furniture. Today only 10% of the original Koa forests survive but due to conservation efforts and it's hardy nature, Koa is not endangered.

Physical properties

The wood is fine-grained can display a number of figure: plain, straight, banded, fiddleback and in one instance quilted. Heartwood can vary from a rich crimson-brown to golden yellow and can vary greatly from log to log. The janka of Koa is around 12250 and it has a specific gravity of 0.55.

As a tonewood...

Koa guitars can vary tonally, in accordance with density and weight. They are most often described as a warm sounding Mahogany to a brighter sounding Rosewood. A lower density koa guitar tends to produce a more mahogany tone, whereas denser sets tend towards the rosewood spectrum.

Subjective tone...

I would broadly characterise the tone of Koa as being similar to Australian Blackwood, with a woody, open tone somewhere between mahogany and rosewood

Availability
As a managed species, Koa stocks are still available and tonewood stocks look limited by healthy. Alternatives exist, namely close cousins Australian and Vanuatu Blackwood. Read more about Australian Blackwood here.