BRUCE SEXAUER: FT-16-C (Adirondack Spruce/Australian Blackwood)
 

As Bruce mentioned in his general build thread/shop journal (http://www.acousticguitarforum.com/f...&postcount=135), he is beginning a new commission for me (My fourth Sexauer!).

This will be a larger guitar whose shape is based upon a J-185. This is a large bodied shape with a narrow waist. Bruce has made many 16” guitars but he has never made a J-185 shape. Because build methodology does not rely upon the use of molds (he builds in the air!), he can build pretty much any guitar shape a client desires. Under the hood I expect that the guitar will have very little to do with a J-185 and will be pure Bruce.

Here are the basic specs. below:

Lower Bout Width: 16”
End Depth: 4-1/4” to 4-1/2”
Scale Length: 25-3/8”
Nut Width: 1-3/4”
String Spacing: 2-1/4”
Fingerboard Radius: 16”
Cutaway: Venetian
Wedge: 1/4”-5/16”

Top Wood: Adirondack Spruce
Body Wood: Australian Blackwood
Neck: One-Piece Honduran Mahogany
Fingerboard: Gaboon Ebony
Bridge: Indian Ebony
Rosette: Koa/Maple
Bindings/Head-plate/End-graft: Amazon & Madagascar Rosewood
Tuners: Schaller GrandTune Gold Butterbean
Fret Wire: Jescar EVO Gold 43080
Case: Harptone

Bruce’s “Journeyman Grade” comment is a little joke between us about the all too common wood grade inflation that we see (e.g. Master Grade, AAAAA, your some special designation to a terroir or history etc.). Bruce selected an aesthetically nice (AAA) set of Adirondack (Red) Spruce for the top that was dead on quarter at the center seam that had little deviation towards to outer edges of the set. More importantly, he was excited about its acoustic potential for this large bodied project. He had a set of “Old Stardard” that we considered, but for this project his instincts recommended this set which had less provenance.

Here is a shot of the unjoined set.

http://i1238.photobucket.com/albums/...pszm4yd36l.jpg

Here is the set being joined on Bruce’s bench.

http://i1238.photobucket.com/albums/...srfmsb5da.jpeg

I believe that this will be Bruce’s 8th Australian Blackwood guitar in the last two decades where he has consistently recorded his work. Aside from the aesthetic beauty of its figure, we chose this set because Bruce felt that its acoustic contribution fell between what a mahogany and rosewood which was supportive of our sonic target on this larger bodied guitar. Australian Blackwood’s physical properties are different than its cousin Acacia (Koa). On average, it tends to be much stiffer and its density can range widely.

Here is a shot of the unjoined set.

http://i1238.photobucket.com/albums/...psfz2eyozc.jpg

Here is the set being joined on Bruce’s bench.

http://i1238.photobucket.com/albums/...s3jg6bnpb.jpeg

More, when I get it....

Boy, you could have fooled me, I would have put good money on that being Koa....gorgeous....congrats on numbet4!

What Tom cannot really know is that this B'wood would be unlikely to be confused with Koa by any knowledgeable person that handled it as is is amazingly dense. I have great expectations for this set. It was harvested in NSW (North South West?), Australia by luthier Tim O'Dea who sold it to me about 20 years ago. Tim told me, if memory serves (and I believe it does), that he had a day job clearing power line slash and got a lot of great timbers such as this as a by product. If only PG&E were so diligent here in California. . .

I believe that NSW likely = New South Wales :)

This is great. I love how much you can trust your builder. Your relationship is well established and is what everyone hopes for. All the best going forward!

Awesome! Love the arch back and 00 (?) he made for you.

Very pretty Blackwood. Looking forward to this build

Eureka!

http://mojoluthier.com/LP17/SJ/templateline.jpg

Or, to be nitpickingly pedantic ...New South Wales ...

🐳 🐳 🐳...auto correct (thanks Murray..:))

OK so I struggle with this as I do not have a Sexauer...

FT: Flat top
16: Lower bout width
C: Cutaway

???

Acacia Genus
 

Both Blackwood and Koa are in the Acacia Genus therefore are close cousins. They are very similar in regard to hardness and density. Bruce may well have a set that is above average hard. The Wood Data Base provides the following: The average Janka hardness for Blackwood at 1160 is a bit less than Koa at 1170. Blackwood is a trifle denser at .54/.64 and Koa at .53/.61. They have very similar grain and I bet that many would not be able to tell the Blackwood that Bruce is using from Koa. Remember someone somewhere misidentified a number of Martin and Coupa guitars from the 1840s as being made of Koa when ion fact they are made of Goncalo Alves. So if a wood the is really strikingly different than Koa can be misidentified as Koa than I am sure extremely nice curly Blackwood can be mistaken for Koa as well. The Wood Data Base is a great site for very good basic information that all wood workers should be aware of and use.

Look at the elastic modulus and you’ll see the key difference between these two Acacias.

Goncalo Alves is SO different from Koa that mistaking one for the other seems like a rookie error to me. I have built with both. I did once see an alleged Pernambuco guitar from a Canadian builder showing at Healdsburg which I instantly recognized as Goncalo Alves. It is not subtle.

I currently have on hand 5 sets of Oz B'wood from three trees, and 10 sets of Koa all possibly from different trees. Of these one of the sets of Koa is noticeably denser than the rest, but the two sets of B'wood which I believe are from the same tree (same flitch) are in another category of density altogether.

The way that the materials are hard is different as well, but hard for me to describe as it is a feeling rather that something I measure. I think the Koa has a shorter grain and a brittle sort of harness, whereas the B'wood has the feeling of a structural timber to it, long fibers and a feeling of general competence which I really like. It occurs to me that it is a bit like comparing Redwood to Spruce, structurally.

The guitars I have made from B'wood seem much more focused to me, more in the Rosewood direction. Whereas on this simplified scale of things so common to guitar talk, the Koa is almost always a lighter more felicitous sound, more in the mahogany direction.

The Koa-Goncalo Alves error was perpetuated for many years. Washburn and Johnson in 1997 published photos of guitar in their book, Martin Guitars, An Illustrated Celebration as being made of Koa. The photo appears on page 43 with th eguitar attributed to being in the Chinery collection. This mis identification was finally corrected in print with the 2013 publication of "Inventing the American Guitar", ed by Shaw and Szego. While I never saw that particular guitar I had the opportunity to look at a similar Martin and Coupa guitar that may well have been made from the same cant. The back and sides of that guitar were identified as Goncalo alves by the US Forest Products Laboratory in Madison, Wi in 2012. Even with that there were a number of well respected people in the guitar world that insisted it was Koa. This error is also possibly behind use of th name Brazilian Koa that is now being used for Goncalo alves as is the name , Brazilian tiger wood. The error probably originated with an amateur identification but it persisted for a number of years.