Official Luthiers Forum!
http://www-.luthiersforum.com/forum/

Koa double top w/ soundport
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=9784		 Page 1 of 2
Author:  Jim Watts [ Mon Dec 11, 2006 6:21 pm ]
Post subject: 
I recently finished this up this guitar and thought I'd post it before the holiday cruch is here which starts tomorrow at my house with a visit from the inlaws, which is good.
This is a koa douple top using some of Shanes lovely Lutz spruce. It's very lightly braced, insprired from a John Calkin piece several years ago in the GAL rag, Ferrari OM, and my experience with my other douple tops. The tops never pull up as much as I think they will under string tension, so I lightend the bracing on this one.
This guitar really rocks! I'm a little uncomfortable stating that as it's my own work but the owner of it really likes it too. The sound is very rich and full with strong bass and trebeles. All I'd hoped for!
So, here's some picts.



Koa from Steve at Colonial.




Sound port detail.



The X is actually about .5 x .25 at its tallest segment.

Looks like I forgot to rotate the photo's, sorry about that. It's late
Just tilt your head .
Thanks for checking it out.
Author:  Rod True [ Mon Dec 11, 2006 6:35 pm ]
Post subject: 
Jim, nice looking guitar there.

That Koa is killer looking.
Author:  Kim [ Mon Dec 11, 2006 7:07 pm ]
Post subject: 
Jim that is beautiful, great work. The Koa is very pretty and that Lutz is spectacular, no wonder she rocks.

Well Done

Cheers

Kim
Author:  Billy T [ Mon Dec 11, 2006 7:26 pm ]
Post subject: 
Ahh! Koa!   
Author:  Alain Desforges [ Mon Dec 11, 2006 7:55 pm ]
Post subject: 
Ouch!!!! That is absolutely fantastic! Drop dead gorgeous!

I love your bridge and that Koa... Well,... let's just say I wet myself.... The silk in that top is just crazy too!

Top drawer, my friend, absolutely TOP DRAWER!!!
Author:  Bob Long [ Mon Dec 11, 2006 11:31 pm ]
Post subject: 
Beautiful guitar Jim!   I'd love to see a close-up of the inlay on the FB.

Long
Author:  LanceK [ Mon Dec 11, 2006 11:32 pm ]
Post subject: 
Jim, you really do nice work!
Author:  Anthony Z [ Tue Dec 12, 2006 3:17 am ]
Post subject: 
That is gorgeous Jim.

Can you describe and share with us what the double top is all about?
Author:  JohnAbercrombie [ Tue Dec 12, 2006 4:23 am ]
Post subject: 
Jim-
Really beautiful and tasteful guitar!

I'm also interested in the 'double top' bit...not the 'hi-tech' style of laminated nomex double top? (I thought they didn't have any bracing to speak of...)

John
Author:  Andy Zimmerman [ Tue Dec 12, 2006 4:34 am ]
Post subject: 
Absolutely beautiful
BTW How do you do your double tops????
Author:  MSpencer [ Tue Dec 12, 2006 4:34 am ]
Post subject: 
Very Nice!

Mike
Author:  Steve Kinnaird [ Tue Dec 12, 2006 5:19 am ]
Post subject: 
Jim, that's beautiful!
More pix, please.

Steve
Author:  K.O. [ Tue Dec 12, 2006 6:22 am ]
Post subject: 
Tis sweet, but how do I get my neck unstuck.
Author:  Cocephus [ Tue Dec 12, 2006 6:32 am ]
Post subject: 
Nice, Jim!
How about a closeup of that fretboard?
Coe
Author:  KiwiCraig [ Tue Dec 12, 2006 9:04 am ]
Post subject: 

Very very very COOL Jim !

I too would like to know about the double top ,,, and a closer look at the fretboard inlays

Superb work Jim


Craig Lawrence
Author:  Serge Poirier [ Tue Dec 12, 2006 9:10 am ]
Post subject: 
I'm in love with this one Jim! WOW WOW WOW!

Gorgeous, elegant, stunning!
Author:  Arnt Rian [ Tue Dec 12, 2006 9:37 am ]
Post subject: 
Very elegant guitar. You do nice work!
Author:  James Orr [ Tue Dec 12, 2006 10:43 am ]
Post subject: 
Jim, oh my gosh!
Author:  CarltonM [ Tue Dec 12, 2006 3:17 pm ]
Post subject: 
You done a good thing, Jim!
Author:  Jim Watts [ Tue Dec 12, 2006 5:17 pm ]
Post subject: 
Thanks for all the kind words.
For those who wanted to see some more of the fingerboard here's a shot. Rotated this time

The fingerboard inlay design was provided by the customer. I had built a previous guitar for him with a variation of this design on it for him several years ago and he recently comissioned this one for his wife.

It's a little of a hodge-podge of a design but mostly it's a Christian theme. On the 7th - 12th frets it's two angles touching wing-tip to wing-tip with 5 cheribum around each angel. This design is belived to have been woven into the curtain of the holy of holies. The 5th fret has a star of Bethlehem and I don't know what the 3rd fret is . I think it might be a piece of jewelry but I'm not sure. There snow flakes on the 12 and 15th fret because they like snowflakes. It gives the guitar a very personal touch for them.
Jim_W39064.0779050926
Author:  Jim Watts [ Tue Dec 12, 2006 5:45 pm ]
Post subject: 
And for those that wanted to know a little more about the double top thing; It actually is a spruce/nomex/spruce top.

I start out with one top jointed and glued together and thickness to about .13-.14.

I then route out two pockets in the top where the honeycomb goes, leaving areas under the bridge, the soundhole and just aorund the edges for the binding solid for ease of installation of the rosette and bindings. I route the pockets so that it leaves a skin of .035.

I then bond in the honeycomb in my vacuum press with epoxy. The honeycomb is a little taller than the depth of the pocket at this point. After its cured I then sand the top to .090 at the center, a little thiner at the edges.
At this point the top looks something (ok, just like) this.



My routing template pins into the two holes you see at either end of the top. Allowing me to precisely locate my pockets where I want them. These same holes locate the top in my side mold when it gets glued on.

I then take a second top and sand the entire top down to .033-.035 and bond the second skin to the first side.

I now have a top that's similar to a standard top only it's a lot lighter in the cored areas than a standard top would be, and the cross grain stiffness is also higher.

I brace my tops as shown in the original photos above. I believe that Charles Fox doesn't brace his "ergo" double top guitars, but he has changed a lot of other things also. Most double tops are occuring in the classical world and are also braced as far as I know.

In the end I get a lighter, stiffer top, with a different flex profile than what a "standard" top has.
They're fun and interesting to build but then again so is a standard top.

I could try to clarify this for anyone if you want more.


Jim_W39064.0787615741
Author:  JohnAbercrombie [ Tue Dec 12, 2006 6:17 pm ]
Post subject: 
Jim-
Thanks for the double top details. Pretty neat concept and the workmanship is A1!
John
Author:  John How [ Tue Dec 12, 2006 7:18 pm ]
Post subject: 
Very nice work Jim!!!
Author:  Dave Anderson [ Wed Dec 13, 2006 2:26 am ]
Post subject: 
Yes,I agree with everyone - Beautiful Work !
Great koa too!
Page 1 of 2 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/