Double Bass "graphite" in neck

[Matthew Tucker]

Luthiers sometimes install graphite rods in basses under the fingerboard, and from what I understand this is to increase stiffness, or reinforce a thin neck.

I'm guessing the technique is simply to routs a channel in the neck under the fb and glue the rod in with epoxy.

I'm also guessing that this is the sort of product used:

Invalid Link Removed

If its not a trade secret, what sort of cross section do you use?

My interest in this is because even if I look at the experience local makers have with guitars and other stringed instruments, I don't know how local (australian) hardwoods will hold up to the high DB tension in the long run, and so a reinforcing stiffener from the outset seems like it might be a good idea.

 

[ToneRanger]

The EUB I've just had made by Bill Paulin has a 3mm x 12mm graphite rod under the fingerboard. I bought it from a local hobby store - about $20 for 1 metre. We chose the 3mm because it fits nicely into a saw slot that was cut the whole length of the neck before the fingerboard was glued on. Bill just epoxied the rod in the slot then trimmed the ends, which are still visible.

Like you, we thought this would provide extra insurance against instability. In my experience with BG's, graphite or steel rods can also eliminate nodes & dead spots.

The bass is very rigid, highly resonant and has no apparent dead spots - I suspect it would be much the same without the graphite, but it was an easy way to gain a little extra confidence in the neck's long-term stability.

 

[ToneRanger]

(I'll post some pics when I can, but my digital camera is currently being repaired)

 

[Tumbao]

Luthiers sometimes install graphite rods in basses under the fingerboard, and from what I understand this is to increase stiffness, or reinforce a thin neck.
I'm guessing the technique is simply to routs a channel in the neck under the fb and glue the rod in with epoxy.
If its not a trade secret, what sort of cross section do you use?

I'd like to know more about it...
http://www.talkbass.com/forum/showthread.php?t=152086&highlight=graphite

 

[KSB - Ken Smith]

I'd like to know more about it...
http://www.talkbass.com/forum/showthread.php?t=152086&highlight=graphite

Ok, ok.. Time has passed so I will report back. First, I have used Graphite Carbon Fiber in many forms for the last 25 years in the Smith Electric Basses we make here. The best results have been with high compression rods or well braided strands. Forget the strands. If I had kept up with that since the early 80s I would have already died from Cancer and not be here to talk about. Get the best high quality rod in the shape that fits your design. Not all Graphite is created equal and neither are the designs or installation methods that people use either. Taking wood out of a neck to put something else in its place can help or hurt depending on how you do it and what you put in it place of the missing wood.

How?.. None of your beezwax...lol . I keep my technique closely guarded like a government secret. But as we have seen on the News too often, 'loose lips sink ships'.. If you know how to do it as we do, equal but different or even better.. Fine, have fun.. A good Graphite product installed favorably can improve the Bass in more than one way..

Now, as far as the link posted above, I did not make the Morelli into a 5er but did put the Graphite in and added a C ext instead during its massive restoration. Arnold went all out and I am proud of his work. He also put Graphite in two other Basses of mine and they too were improved to my ear and feel. One was only a Neck graft/FB replacement so I could tell by the tone. The other two were restored completely with Top re-graduation as well and the Back on the Morelli so there were other factors that improved the Bass other than just the Graphite.

My final word on this (this posting only!) is this, 'if it ain't broke, don't fix it!'... If you are getting a new FB put on, try the Graphite at that time. If you don't need a new board, then don't try taking off the board to re-place it just to try the Graphite and risk loosing the FB and an added expense much greater than the Graphite job itself. My Martini is in for a few little things as well as an ext. and I wish I would have had him do this b4 but that was over a year ago at a different shop and it's not worth ripping off a good board for the Graphite. If the neck ever breaks on the Martini, then within the repairs and new neck graft, I will add the Graphite. I have decided to do this to every Bass I own, buy and restore as long as it needs a new Fingerboard. If the FB can come off easily or is coming off anyway then I would do it as well.

Just my 2cents...lol

 

[Nick Lloyd]

I'm guessing the technique is simply to routs a channel in the neck under the fb and glue the rod in with epoxy.


My interest in this is because even if I look at the experience local makers have with guitars and other stringed instruments, I don't know how local (australian) hardwoods will hold up to the high DB tension in the long run, and so a reinforcing stiffener from the outset seems like it might be a good idea.

I've been using a 1/4" x 3/8" rectangular graphite rod in my new basses, and sometimes in necks that have warped, and also in neck repairs. I didn't see this dimension listed on the link you provided... Luthier's Mercantile out of Healdsburg, California sells different size graphite rods.

PM me if you need help designing your routing jig.

What species of hardwoods are you considering?

 

[Matthew Tucker]

Thanks Ken and Nick for those pointers.

I don't really know about wood yet. We don't have true maple.

Blackwood (a variety of acacia) is used in guitar backs, sides and necks. I have used Tasmanian oak (a variety of eucalyptus) quite a lot, it stays straight, is hard, and can resonate quite well . (I think axe-handles are made from it too) But a bit boring to look at. And you need to find a bit without resinous streaks.

Blackbean (a hard local rainforest wood) is one of my favourites for working with - looks great too, but I've no idea how it performs musically. There are many varieties of close-grained, hard gum (eucalyptus) to try, redgum,, yellow box, ironbark etc and plenty of well-seasoned recycled wood (warehouse beams etc) for necks and ribs. Some of these might be too brittle.

Specially quarter-cut wood, I don't know, but I should be able to find some closegrained straight hardwood to work with.

There is another wood from Western Australia called Jarrah that is sometimes used in instruments, but I have little experience with it. Tasmanian Myrtle and sassafras are also available but again, I have no experience with these.

I figure I should be able to get my hands on some fruit woods, too. We grow fruit in Australia.

For the belly I'm thinking King Billy pine, perhaps Silky Oak (lacewood(?)), perhaps Bunya pine.

I'm in France right now, so I have to look around when I get back in January.

 

[bribass]

Ok, ok.. Time has passed so I will report back. First, I have used Graphite Carbon Fiber in many forms for the last 25 years in the Smith Electric Basses we make here. The best results have been with high compression rods or well braided strands. Forget the strands. If I had kept up with that since the early 80s I would have already died from Cancer and not be here to talk about. Get the best high quality rod in the shape that fits your design. Not all Graphite is created equal and neither are the designs or installation methods that people use either. Taking wood out of a neck to put something else in its place can help or hurt depending on how you do it and what you put in it place of the missing wood.

How?.. None of your beezwax...lol . I keep my technique closely guarded like a government secret. But as we have seen on the News too often, 'loose lips sink ships'.. If you know how to do it as we do, equal but different or even better.. Fine, have fun.. A good Graphite product installed favorably can improve the Bass in more than one way..

Now, as far as the link posted above, I did not make the Morelli into a 5er but did put the Graphite in and added a C ext instead during its massive restoration. Arnold went all out and I am proud of his work. He also put Graphite in two other Basses of mine and they too were improved to my ear and feel. One was only a Neck graft/FB replacement so I could tell by the tone. The other two were restored completely with Top re-graduation as well and the Back on the Morelli so there were other factors that improved the Bass other than just the Graphite.

My final word on this (this posting only!) is this, 'if it ain't broke, don't fix it!'... If you are getting a new FB put on, try the Graphite at that time. If you don't need a new board, then don't try taking off the board to re-place it just to try the Graphite and risk loosing the FB and an added expense much greater than the Graphite job itself. My Martini is in for a few little things as well as an ext. and I wish I would have had him do this b4 but that was over a year ago at a different shop and it's not worth ripping off a good board for the Graphite. If the neck ever breaks on the Martini, then within the repairs and new neck graft, I will add the Graphite. I have decided to do this to every Bass I own, buy and restore as long as it needs a new Fingerboard. If the FB can come off easily or is coming off anyway then I would do it as well.

Just my 2cents...lol

Ken, I found this old thread about carbon fiber rods to firm up necks.

It gave me confidence in my decision to have this done w/ a new fb.

The neck on my German bass has been having some seasonal warping issues and this has caused the scoop in the fb to be too drastic, making the bass harder to play than it should be. I've been thinking of having this done for a long while now along w/ a new fb. I could just have the fb planed in the lower and upper positions to compensate for the slight warpage, but the fb that I had put on about 12 or more years ago (I won't mention the shop) was never quite right. Not a great piece of ebony, I've been told, and the shape was never right either. I don't want to throw $ at this questionable fb so I'm taking the plunge w/ a nice new board and cf rod to firm up the (beech) neck. How do you think this will affect the sound? As is the bass has a nice punchy, but mature tone. You're typical 1920's or so 3/4 German gamba shop bass. A good amplifying Jazz bass w/ a nice arco sound that has served me well for many years and was my main bass before obtaining the Prescott. Now it's my go to 'in the trenches' bass for work a day gigs that may be too risky for the Prescott and for flying out of town.

Bri

 

[Don Harris]

Anybody care to describe their routing jig for adding a carbon fiber rod to an existing bass?

 

[Jake deVilliers]

Its pretty basic Don, just a 3/4 ply 'L'. The top ripping has a slot partway for the router bit and peeking. I have a fence screwed on the left side the appropriate distance from the slot. The 'L' comes down on the left side so I can shim and clamp as necessary.

I clamp the vertical at the heel and the horizontal at the scroll. Not fancy bit it works well.

I could try to find it and send you a photo if you want. We're on the last leg of an extensive renovation that included my workroom and lots of non-daily-use stuff is piled at the back of my machine shed.

 

[Andrew McGregor]

If you're looking for carbon rod to use for this, Avia Composites are one of the top manufacturers: http://www.aviasport.net/composites/index.htm

 

[ctregan]

I am making a neck out of cherry wood that will need some reinforcement since it is not as structurally strong as maple. My idea is to use two strips of carbon fiber angled towards the center (a V shape in cross section of the neck). Also, the space between the two strips would increase or widen as it progresses toward the heel. I have done some mock-ups that seem to suggest this may be a stronger method, (but the more difficult to mill).
With only one strip of carbon fiber (implanted 90 degrees off the fingerboard), it seems like the neck could still move side to side. Wobbly necks absorb string energy from what I understand.
Cherry is pretty wood, and carves easily, but a little on the soft side. I hope the carbon fiber, plus the ebony fb, will give it the enough strength for the job.

 

[KSB - Ken Smith]

Ken, I found this old thread about carbon fiber rods to firm up necks.

It gave me confidence in my decision to have this done w/ a new fb.

The neck on my German bass has been having some seasonal warping issues and this has caused the scoop in the fb to be too drastic, making the bass harder to play than it should be. I've been thinking of having this done for a long while now along w/ a new fb. I could just have the fb planed in the lower and upper positions to compensate for the slight warpage, but the fb that I had put on about 12 or more years ago (I won't mention the shop) was never quite right. Not a great piece of ebony, I've been told, and the shape was never right either. I don't want to throw $ at this questionable fb so I'm taking the plunge w/ a nice new board and cf rod to firm up the (beech) neck. How do you think this will affect the sound? As is the bass has a nice punchy, but mature tone. You're typical 1920's or so 3/4 German gamba shop bass. A good amplifying Jazz bass w/ a nice arco sound that has served me well for many years and was my main bass before obtaining the Prescott. Now it's my go to 'in the trenches' bass for work a day gigs that may be too risky for the Prescott and for flying out of town.

Bri

Brian (and anyone else listening), you have 3 basic components here. The Neck, the FB and the CF. If a Neck itself is bad, I don't see the value in fixing it with CF and a new FB. It is very possible that the Neck will continue to move and either separate from the FB or take the FB with it, with or without the CF installed. If the Neck is too stiff to give, then separation is a strong possibility.

Now, providing the Neck is in good shape, the CF will help stiffen it physically but smooth out the notes harmonically and make them sound more even. There is this other part that may or may not agree with this and that's the Bass itself.

The new FB will also help just as much in the sound and structure if not more. It is also important to know that CF can bend as well. The CF though has 'good memory' and will want to return to its original position when not under tension so its a stabilizer as well.

I have had the CF added to several of my Basses but this was during restorations where a new FB was required as well as a Neck Graft in some. My Martini is getting a Neck graft with CF added and if possible will re-use the FB that is less than 4 years old if it can be saved as it is still fairly thick. The main concern is re-fitting the C-Ext after all is said and done. The CF is just Icing on the cake!

 

[bribass]

Brian (and anyone else listening), you have 3 basic components here. The Neck, the FB and the CF. If a Neck itself is bad, I don't see the value in fixing it with CF and a new FB. It is very possible that the Neck will continue to move and either separate from the FB or take the FB with it, with or without the CF installed. If the Neck is too stiff to give, then separation is a strong possibility.

Now, providing the Neck is in good shape, the CF will help stiffen it physically but smooth out the notes harmonically and make them sound more even. There is this other part that may or may not agree with this and that's the Bass itself.

The new FB will also help just as much in the sound and structure if not more. It is also important to know that CF can bend as well. The CF though has 'good memory' and will want to return to its original position when not under tension so its a stabilizer as well.

I have had the CF added to several of my Basses but this was during restorations where a new FB was required as well as a Neck Graft in some. My Martini is getting a Neck graft with CF added and if possible will re-use the FB that is less than 4 years old if it can be saved as it is still fairly thick. The main concern is re-fitting the C-Ext after all is said and done. The CF is just Icing on the cake!

Thanks Ken. Ofcourse there is no telling what wood will actually do, but both Arnold and Jeff seem to think that this would solve the problem. I don't think either felt the additional expense of a neck graft or neck/scroll replacement is warranted here. The thicker, better board alone may do the trick, but as you say, while your in there might as well go for the CF as well. I'm betting the board and CF can only improve the sound and stability of this already great sounding bass.

BG

 

[KSB - Ken Smith]

Thanks Ken. Ofcourse there is no telling what wood will actually do, but both Arnold and Jeff seem to think that this would solve the problem. I don't think either felt the additional expense of a neck graft or neck/scroll replacement is warranted here. The thicker, better board alone may do the trick, but as you say, while your in there might as well go for the CF as well. I'm betting the board and CF can only improve the sound and stability of this already great sounding bass.

BG

I agree, it's well worth the try. By the way, while at Jeff's did you see my Loveri he's working on?

 

[bribass]

I agree, it's well worth the try. By the way, while at Jeff's did you see my Loveri he's working on?

Yes, he had it on his bench. Looked like it was coming along nicely w/ some cracks filled in w/ wood and had some sand bag(s) as if to flaten it. Interesting wood on that back. Twisty, burly grain.

Bri