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All Koa OLF SJ
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=7749		 Page 1 of 1
Author:  Steve Saville [ Sat Jul 29, 2006 2:10 am ]
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I just took an order for an OLF SJ. The customer wants it to be all koa with bloodwood bindings and ebony fretboard/bridge. This will be my first experience with koa. I'm excited, but I have some concerns and want it to be right.

I have been doing some reading and believe the top should be about .080" thick, and the braces need to be a little taller. I'm not sure how much taller they should be and if my thickness is right.

He also wants it to be a 24.9" scale. I'm concerned about that. Should the koa top be a longer scale to get as much energy from strings as it can? Would a koa top do better with a smaller top, like a 000 or OM?

To get the best tone would you recommend a higher energy bridge/fretboard/bridge plate like EI rosewood?

Lots of questions - what am I missing that I should be asking?

Thank you for your help!
Author:  Andy Zimmerman [ Sat Jul 29, 2006 3:29 am ]
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I have built one all Koa guitar and currently I am making my 2nd. Both are
OM's not SJ's but they are 24.9 scale.
I thicknessed my top to around 0.105
I used my standard braces.
My fretboard and bridge were ebony. EIR bridge plate.

With my N of 1, I don't have a lot of experience, but I really didn't change
anything from my typical construction.
Author:  CarltonM [ Sat Jul 29, 2006 5:23 am ]
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I think some would suggest that you convince your customer to accept a rosewood bridge. There's a solid reason that classical guitars traditionally have ebony fingerboards and rosewood bridges--the most sound for your money. With a hardwood top, he's going to want as much string energy going to the soundboard as he can get, and ebony will absorb some of it.

As I understand it, ebony doesn't have the same effect as a fingerboard, because it also stiffens the neck, which is good for transferring string vibration to the top.

I'm not an expert on this topic, so I could just be blowin' smoke. Hopefully, someone else will clarify.
Author:  Mark Swanson [ Sat Jul 29, 2006 5:37 am ]
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I'm getting ready to build an all-koa guitar as well, so I'm following with interest. I agree with the rosewood bridge, extra weight and mass on the top won't help here, I think. And also, I may go thinner than a spruce top, but not that much and I think .080 would be way too thin.
Author:  Don Williams [ Sat Jul 29, 2006 6:25 am ]
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I've got plans for eventually building an all Tasmanian Blackwood guitar, probably an OM, so I too will be following the thread closely.
Author:  Michael Dale Payne [ Sat Jul 29, 2006 4:24 pm ]
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I have built several Koa topped guitars. they make great tops. Andy is right .105-.110 is the range you want on your top. On a 12 fret 24.9 scale you will need to shift the bracing and sound hole accordingly and could take the top down to .098 maybe but no more that that.
Wonderful blended tone Koa tops make. When voicing they will sound a bit bassy but not to worry once mounted to the rim the highs get clear.


Don't forget to fill the pores in this top!!!!!
Author:  Mark Swanson [ Sun Jul 30, 2006 2:12 am ]
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There's some other things to think about too. I bought a pice of Koa for a top from Bruce Kreps of Notable Tonewoods at the GAL meeting. I thought it would be a great chance to pick one out there, so that I could speak directly to him about what I wanted in a top.
He knew more than I did, and helped me with good advice, and selected a piece for me.
He told me that lighter colored Koa would work better because it was always less dense than the dark stuff and for a top you want a lighter, less dense piece. He also said that runout should be looked at too- much of the high-figure stuff has a lot of runout in it, because runout isn't usually as big of a factor if you are choosing wood for a back- but for a top it is something that you should keep in mind. He told me carefully think about any sapwood that you might use in a top and make sure it's good before you use it- the top I have has some in the center. A piece that isn't so highly-figured is going to be more stable across the whole top, and really when you think about it a guitar can have plenty of figure on the back and sides and would look very good with a top that was more even and didn't have as much figure as the rest of the guitar. Most of us are used to spruce and cedar anyway! Then again a guitar made out of all-matching Koa is striking at least!
Well, it is good advice and a good thing to consider when choosing a top. Mark Swanson38928.4688541667
Author:  Howard Klepper [ Sun Jul 30, 2006 6:41 am ]
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Steve, you haven't said what kind of music your client plans to play, or how he hopes the guitar will sound. That's where I begin with a client.
Author:  Steve Saville [ Sun Jul 30, 2006 8:07 am ]
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Great point Howard.

This guitar will be used for moderate strumming about 90% of the time with fingerstyle on the remaining 10%.
Author:  TonyKarol [ Mon Jul 31, 2006 12:35 am ]
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I never go below .100 on a full size top (maybe to 90-95 if its a stiff piece for a single 0). The two koa tops I did, I was still looking for the right crossgrain stiffness - one was the double neck, I left it thicker at .125-130, the other was a jumbo, it was more in the .105-110 range. The problem with thinner tops is I am afraid of too much brace telegraphing thru, and of course, over time it will likely belly more than others.
Author:  Steve Saville [ Mon Jul 31, 2006 2:12 am ]
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Wow, you guys are great!

.105" - .110" it will be.

This going to be a 14 fret model.

Author:  Michael Dale Payne [ Mon Jul 31, 2006 2:25 am ]
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Your customer will love this as a finger style guitar. Koa top has a wonderful malonic tone, clear highs, warm distinct mid range and smooth but penetrating bass
Author:  Steve Saville [ Mon Jul 31, 2006 4:33 am ]
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Michael,
I'm a fingerstyle guy myself. I've always preferred cedar tops. I have played a few koa topped guitars - Taylors and Goodall's. With the Taylors. it was a mixed bag for me. The 2 jumbo sized Kenny Loggins models were great, while the K12 smaller bodied guitars with not so good. The latest Goodall I played was a baritone. That was outstanding for fingerstyle.
You made me rethink this. Is koa just good for fingerstyle, or should it be on a larger body to sound good? Should short scale be avoided?
Author:  Michael Dale Payne [ Mon Jul 31, 2006 4:45 am ]
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I have build 4 OMs with Koa tops, 2 were EIRW back and sides all were for celtic finger style or folk finger style players. Personaly I love this combo on an OM. The OLF SJ is a slightly bigger and deeper body. so I think it will be fine. Brace it well but don't over brace it.
Author:  Steve Saville [ Sat Aug 05, 2006 5:42 pm ]
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Below is a picture of the sides laid across two back/top sets. The set in the lower portion of the picture is what I intended to build this guitar from - there are 4 pieces there for back and top. After reading this thread, especially what Mark Swanson said above, I am a bit concerned about the higher figure in that set for a top. The upper set is more quarter sawn. I am not good at looking for grain runout.
Would the set at the top of the picture make a better sounding guitar? The tap tone is more pleasing to me. Would the difference likely be big, or pretty small?
Thanks!


Author:  Steve Saville [ Tue Aug 08, 2006 2:00 am ]
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Hmmm, I thought someone here might have an opinion on the 2 top options in the post above.

Anyone?
Author:  CarltonM [ Tue Aug 08, 2006 3:17 am ]
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Steve,

I think, for a top especially, you should go for the most quartersawn wood. I also think the tap tone is your friend here. Go with your instincts. You'll prove yourself either right or wrong, but either way, you'll learn something. Besides, no matter what you do, it's going to sound like a guitar!
Author:  Steve Saville [ Tue Aug 08, 2006 7:36 am ]
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[QUOTE=CarltonM] ......Besides, no matter what you do, it's going to sound like a guitar![/QUOTE] Thank you for that simple, elegant, and needed reminder.
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