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Sven
08-08-2014, 03:05 AM
I decided to put some carbon fibre into a few necks but ran into a problem since I wanted the slots to taper in depth from 12 mm to zero. The method I came up with might not be for everyone (my methods rarely are) but it was simple and made me feel clever so I'll post a link to the blog post that describes it here.

http://www.argapa.blogspot.se/2014/08/installing-neck-reinforcement-rods.html

The trick was to use the tapered cf wedges as spacers under the neck blank while making the slots, thereby avoiding measuring to a large extent.

You can see a pic here if you don't want to read the post:

69785

Beau Hannam Ukuleles
08-08-2014, 10:40 AM
That is a total waste of time and expensive CF which will create toxic dust when you cut it down.

Also you have made the weakest part (near the nut) have the less amount of add stiffness.

Just bury those suckers full depth and forget about em :)

ericchico
08-08-2014, 11:40 AM
On the subject of CF rods in the neck will one down the middle do fine or is 2 needed to help stop twisting. Not trying to hijack just curious. I am using 1 square tube for now and would like to upgrade to carbon fiber.

Beau Hannam Ukuleles
08-08-2014, 12:31 PM
one down the middle is fine.

Bruce Sexauer
08-08-2014, 02:26 PM
I use 2 1/8 x 7/16 about 1/2" apart in my steel string Ukes and that works very well. CA seems to work well to bond them. HHG does not, oddly.

Michael Smith
08-09-2014, 05:56 PM
Most if not almost all of the time zero is plenty.

Sven
08-10-2014, 11:38 PM
Oops - sorry for wasting your time Beau. I chose to add the carbon fibre since I wanted to add some protection from warping. Two cuts and a different material near the surface will give me that. I'm not really worried about the strength of the necks, as Michael pointed out they would be fine in most cases as they were.

Paul Henneberry
08-11-2014, 01:40 PM
Hi Sven,
that is a VERY clever solution. Going back a bit, how did you cut the tapers? I've never used CF and have been put off by it's reputation of being brutal on edge tools. I've got one of those proxon saws and it is very cute but very overpriced by the time it is retailed in Australia. If you cut it on the proxon, which blade did you use?
cheers
Paul

Rob-C
08-11-2014, 01:54 PM
As a matter of interest, just how toxic is the dust from carbon fibre composite? Is it really any more hazardous than wood dust, or dust from sanding GRP composites?

Beau Hannam Ukuleles
08-11-2014, 04:50 PM
You didn't waste my time :)
I, however, was trying to save you time by pointing out that what your doing (not simply embedding the CF full depth for its length) was a waste of time and material.

No warping will (should) happen with seasoned wood on ukes, regardless of using (1 or 2) CF or not,

DennisK
08-11-2014, 05:09 PM
I'm curious about CF dust danger as well. My guess is that it would be on level with shell inlays. Not toxic, but small and sharp and permanently lodges in lungs. But then there's the resin binder as well, and I'm not sure what kind of properties that has after it's cured.

Sven
08-11-2014, 08:52 PM
Ok Beau, thanks then for the info. I'm sure you're right about the cf. But I'm still rather pleased with using the wedges as, erm, wedges for sawing the slots.

Paul - I cut it on my proxxon mini bandsaw, don't know the effect on the blade really.

Rob - it is a nasty substance, and as I think of it more as a strengthening through laminating (but without cutting through the blank) I have now started pondering adding splines of wood instead of cf. That would make my life a lot easier. Or at least the part of my life I spend in the shop doing this.

Kekani
08-11-2014, 10:09 PM
Just for conversation, I had to find a way to NOT route it so deep, as I actually sanded through to the cf on one neck. So, I thought I'd leave the cf a little proud - 1/8"x3/8" (or is it x1/4"?).

I initially thought I'd sand it down level, but once I did the first one, I made a different fretboard taper jig. End of story is I route a very shallow 1/8" slot underneath the fretboard, which lines up with the cf rod. Since I've done more than a few fretboards with inlays, this is a great way to center the fretboard, without pins. Plus, I get to taper my fretboard on the router table, instead of table saw. Much cleaner.

Just a different means to an finished instrument. The guys from who attended my class at last year's UGH Exhibition had some positive comments, though I'm not too sure how many will actually incorporate that into their builds.

Beau Hannam Ukuleles
08-14-2014, 04:18 AM
... So, I thought I'd leave the cf a little proud - 1/8"x3/8" (or is it x1/4"?).

...I route a very shallow 1/8" slot underneath the fretboard, which lines up with the cf rod. Since I've done more than a few fretboards with inlays, this is a great way to center the fretboard, without pins

Great Idea Aaron!-
so you
1-cut the fret slots.
2- route a shallow trough in the bottom of the FB (to match to raised 1/8" CF in the neck.
3- use a tapered jig that fits to the FB trough to route the FB taper??

Do you epoxy the FB on??
Sounds like a really good method :)

Kekani
08-14-2014, 06:12 AM
Great Idea Aaron!-
so you
1-cut the fret slots.
2- route a shallow trough in the bottom of the FB (to match to raised 1/8" CF in the neck.
3- use a tapered jig that fits to the FB trough to route the FB taper??

Do you epoxy the FB on??
Sounds like a really good method :)

After I saw your nail thingy, I was wondering if you'd be interested in this.

There's an image of the jig on the BIUG Gallery of the UGH Exhibition last year. Its the 4th image after I start with my M&T jig.
http://www.bigislandukuleleguild.org/gallery/ugh---exhibition-2013.html

And you have the sequence correct, although, I guess you could route the slot first, then cut the fret slots.

I epoxy the rod in, but LMI glue the board on. If I'm in the mood, I'll use epoxy on Cocobolo.

You cannot image how easy it is to glue on fretboards this way. The hardest part is jigging up for it. But after the M&T, my "centerline" jigs make everything so much easier, and more accurate. For me, anyway.

Beau Hannam Ukuleles
08-14-2014, 07:35 AM
Nice!
The only problem i can foresee would be slippage forward or backwards, but lmi is pretty tacky so its probably not a problem.

Aaron- are you around is october as ill be in Oahu for 2 weeks

Kekani
08-14-2014, 09:52 AM
Because my headstock veneer is proud to the fretboard gluing surface, I can just slide the fretboard and butt it up against the veneer, & its very easily controllable and clamped. Note: I used to have the nut go between the veneer & fretboard, but now put the nut in the fretboard, like Fender Guitars. I do this for a number of reasons, first one being finishing, but that's another story.

I'll email my schedule to you later. Would be good to hook up.

Sven
08-22-2014, 01:30 AM
Well I do have an important piece of information that I must share rather than to let the thread die and be forgotten. Slicing the cf on my bandsaw totally killed a blade and I am a bit worried about the dust residue in it. I hope I haven't inspired anyone to waste blades.

So don't do this. At least not with carbon fibre, I might actually continue doing something similar but with wooden wedges if I feel like it. The reason would be to strengthen the neck with a partial lamination (yes I know most necks wouldn't need it).

Beau Hannam Ukuleles
08-22-2014, 06:34 AM
Dont wedge, just inlay full depth :)

1- Takes more time
2- Loss of expensive material
3- Less strong

I cut the CF rods to lenght with a hacksaw