Official Luthiers Forum!

I got some rods from them recently and they are very nice! Every bit as nice as anything else out there at half the price! CAn't beat that kinda deal guys! Get em!

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John Mayes
http://www.mayesluthier.com

What size is most commonly used for acoustic necks?

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JJ
Napa, CA
http://www.DonohueGuitars.com

JJ: I am using .125" x .335", One on either side of the truss rod.

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tim...
http://www.mcknightguitars.com

Thanks, Tim...I'll give it a try.

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JJ
Napa, CA
http://www.DonohueGuitars.com

I use .250 x .187 one on each side.

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John Mayes
http://www.mayesluthier.com

and I typically use .25 X .25 one on each side.
Thanks for the kind word John, glad you like em.

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Jim Watts
http://jameswattsguitars.com

Wow...3 posts...3 different recommendations! What are your rationales?

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JJ
Napa, CA
http://www.DonohueGuitars.com

Y'all realize that to make a member stronger, it is 8 tiems more effective to add height than width, right? First semester engineering...

Jim, with your two 1/4" square pieces, as an example, if you simply made them twice as tall, you could get away with 1/32" thick, instead of 1/4". In other words, a piece of .031" thick x 1/2" tall CF on either side of the rod will give you the same strength as the two 1/4" square ones. Much less weight...

But more important, you can now double the thickness, and use .062" for each one, and double the stiffness, and still bank a sizable weight savings.

Always add depth before width, if the space allows. In a neck, there's plenty of room for 1/2" deep CF....

Quick question at this juncture: is there a website? Because googling ain't helping.

The link is here on the OLF! Didn't see it until just now.

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D..

Uh, right. OK. I'm officially blind :-)

[QUOTE=Mario] Y'all realize that to make a member stronger, it is 8 tiems more effective to add height than width, right? First semester engineering...

Jim, with your two 1/4" square pieces, as an example, if you simply made them twice as tall, you could get away with 1/32" thick, instead of 1/4". In other words, a piece of .031" thick x 1/2" tall CF on either side of the rod will give you the same strength as the two 1/4" square ones. Much less weight...

But more important, you can now double the thickness, and use .062" for each one, and double the stiffness, and still bank a sizable weight savings.

Always add depth before width, if the space allows. In a neck, there's plenty of room for 1/2" deep CF....[/QUOTE]

Mario, that said, (and I agree with the post) but would it not also be good to give side to side stiffness? If that were the case, you would also want the "height" to be in the horizontal direction. So a .25x.25 would give stiffness in both directions. I laminate my necks so it isn't an issue but I would think there is a case where a solid mahogany neck might want to bow in the side to side direction. I've seen it on old martins.

I've never, ever, seen a neck bow side to side. Twist, yes, but never side to side. I guess it -can- and does happen, but it would be so rare that we don't need to build for it, and I would assume that if a piece of wood has that much tension and stress built-in, it will move no matter how much CF you put into it.

CF shouldn't be used to make bad wood usable. Bad wood is bad wood. CF should be seen as a way to make good wood even stiffer, more stable.

That said, I've never used any in a neck, yet...., but I did have to replace a neck last year that was so rubbery it was all over the place. THAT one could have used lots and lots of CF <bg>. Pretty flawless looking piece of mahogany it was, too.... Oh well, build enough of them, and it has to happen.
Mario38719.4589467593

[QUOTE=Mario]
Jim, with your two 1/4" square pieces, as an example, if you simply made them twice as tall, you could get away with 1/32" thick, instead of 1/4". In other words, a piece of .031" thick x 1/2" tall CF on either side of the rod will give you the same strength as the two 1/4" square ones. Much less weight...
[/QUOTE]

Mario, you comments are right on as far as the hieght width thing. I like the 1/4 X 1/4 for a few reasons, primariliy because I'm already set up on a router table with a 1/4 bit. I then route a 1/4 X 3/8 deep groove on either side and cap off the cf with a hardwood strip. I think it would be impractical for me to route a 1/32 X 1/2 groove as the length to diameter ratio is pretty large there
So it as much for practicallity as structure. While your right about the stiffness part, more carbon will create a more stable neck simply because the cf is a more stable material, but if you want stiffness taller is always better.

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Jim Watts
http://jameswattsguitars.com

Composites from Los Alamos? Have you held a geiger counter up to them
yet? Howard Klepper38719.6666435185

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Hi Jim,

I couldn't get your link to work.

By the way, I grew up just up the road from you in Pagosa Springs, CO. We took a field trip to Los Alamos when I was in high school.

Jimmie,
It should work I think, it works for me. Maybe Brock could look into it, but try itagain as maybe the server was down or something. Thanks for checking or trying to check it out.
Howard, No radioactive Carbon fiber coming out of here!
.
Actually Los Alamos is really a nice seculed place. Great place to live!

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Jim Watts
http://jameswattsguitars.com

"No radioactive Carbon fiber coming out of here"
That's very interesting! Specially milled, low boron carbon was used as a moderator in early reactors(a la Chernobyl). Very interesting!!

Did they... just find this stuff... lying around?

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

Jim:
I received my CF rods today. Thanks for the fast and friendly service, and your willingness to custom size them to my specs. They look great too. Too bad we are the only two people who will ever see them ;)

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tim...
http://www.mcknightguitars.com

Very glad you like them Tim

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Jim Watts
http://jameswattsguitars.com

[QUOTE=Jim_W] Jimmie,
It should work I think, it works for me. Maybe Brock could look into it, but try itagain as maybe the server was down or something. Thanks for checking or trying to check it out.
Howard, No radioactive Carbon fiber coming out of here!
.
Actually Los Alamos is really a nice seculed place. Great place to live![/QUOTE]

It works fine for me. Anyone else having trouble?

I am thinking it must be a minor server glitch somewhere.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I checked for a 1/8 by 3/8 bar. That is the size I typically use on either side of the neck and I couldn't find them in the offerings. Does Los Alamos make such a layup?

John

OK, I retract that question. I see it. I'm gonna get some NOW!

What thickness is appropriate for laminating for braces - 0.020?

-Mark

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Pullman, WA

The more I know, the more I know I don't know.

trippguitars.com
OR
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I use .022".

.020" will be fine...

Jim, since Tim mentioned custom sizes, would 1/8"x1/2" be in the works? Just curious...