What makes necks warp, and how much can truss rods prevent or fix that?

[greenfrog]

I have a Lanikai baritone (LUTU-21b, from before they started adding truss rods) that has a warped neck. The warp is one-sided (only on the side under the lowest two strings) and towards the headstock end of the neck, making that part of the neck (and the first several frets on it) stick up a bit closer to the strings than they should and buzz unless the action is kept high at the saddle end. I can’t see the warp myself (I thought I just had loose frets) but it was bad enough that a luthier spotted it immediately.

I have a bunch of questions to try to learn from what happened to it, so I can avoid this happening in the future.

1. Why would a neck warp like this? It was bought used (no idea how last owner handled it), then kept in a cold basement (but humidified regularly in the winter) for a few years during the pandemic when I wasn’t there to play it, then eventually I asked for it to be shipped to me during what turned out to be one of the hottest weeks of summer. So it’s been through a lot, but I’m curious if one thing stands out as a likely cause.
2. Is there anything I should do (or avoid) now to keep the warp from getting worse? Put a second humidifier in the case closer to the neck? Loosen the strings when not playing?
3. Could a truss rod have prevented or fixed this?
4. Is it common for baritones without truss rods to eventually develop neck problems (if not this specific problem, then some other neck problem)? If so, how long is it normal for a baritone without a truss rod to last before the problems start?
5. Are warped necks fixable? A luthier advised me to put my money towards an eventual new ukulele instead, but if a more expensive baritone with no truss rod developed neck problems are there ways it could be fixed?

 

[John Colter]

There are two main reasons why necks warp. One is the tension of the strings pulling the neck upwards at the headstock. The other is that some individual pieces of timber have built in stresses which relieve/resolve over time, pulling the neck out of shape. The former tends not to be a problem with the smaller sizes of ukulele. The latter can affect anything made of wood and is quite unpredictable.

I know nothing about baritones or truss rods.

 

[saltytri]

You ask some very good questions that focus on what might be done after the horse is already out of the barn. Without, I hope, being seen as minimizing your problem or hijacking your thread, this seems like a good place to remind us all of proper building practices that can minimize problems with a neck down the line.

In answer to your first question, there are some things that can be done to forestall these problems. First, the builder should use wood that is among the most dimensionally stable species, such as Honduran mahogany, Spanish cedar, Alaskan yellow cedar and Port Orford cedar. The billet from which neck will be made should be seasoned for as long as possible. A period of years isn't too long. Even relatively stable wood that has been seasoned can warp or twist due to internal stresses when it is cut into smaller pieces. Long before the wood is actually shaped into a neck, it should be cut to the approximate shape of a neck so that any stresses in the wood are relieved and then set aside for at least a few months if not longer before being finally shaped. I always have a couple dozen roughed-out neck blanks sitting on a shelf.

Although not all builders advocate the use of carbon fiber reinforcement, I now use two 1/4 inch rods placed side-by-side down the center of the neck to inhibit changes over time. I don't have any direct experience with fixing a twisted neck but have read that people in the guitar world have had some success by using various methods to mechanically apply counter-twist over an extended period. In fact, my son-in-law had success with this in correcting twist in the neck of a very nice USA-built Fender Strat.

Generally speaking, an adjustable truss rod can be useful to adjust the amount by which string tension bends the neck into an arc but probably won't be of much value in either countering or repairing the tendency of a neck to twist.

Without knowing more and actually seeing your instrument, I tend to agree with the advice of your luthier that attempting a repair may not be the best idea. You might want to explore whether the problems that you are experiencing could be minimized by careful adjustment to the setup.

It wouldn't be surprising if we can all learn something useful from your experience. Your question is an interesting one and may be applicable to some of the instruments that other UU members enjoy playing, so please let us know how you make out and whether you are able to solve this problem to your satisfaction. Good luck!

 

[Ziret]

You ask some very good questions that focus on what might be done after the horse is already out of the barn. Without, I hope, being seen as minimizing your problem or hijacking your thread, this seems like a good place to remind us all of proper building practices that can minimize problems with a neck down the line.

In answer to your first question, there are some things that can be done to forestall these problems. First, the builder should use wood that is among the most dimensionally stable species, such as Honduran mahogany, Spanish cedar, Alaskan yellow cedar and Port Orford cedar. The billet from which neck will be made should be seasoned for as long as possible. A period of years isn't too long. Even relatively stable wood that has been seasoned can warp or twist due to internal stresses when it is cut into smaller pieces. Long before the wood is actually shaped into a neck, it should be cut to the approximate shape of a neck so that any stresses in the wood are relieved and then set aside for at least a few months if not longer before being finally shaped. I always have a couple dozen roughed-out neck blanks sitting on a shelf.

Although not all builders advocate the use of carbon fiber reinforcement, I now use two 1/4 inch rods placed side-by-side down the center of the neck to inhibit changes over time. I don't have any direct experience with fixing a twisted neck but have read that people in the guitar world have had some success by using various methods to mechanically apply counter-twist over an extended period. In fact, my son-in-law had success with this in correcting twist in the neck of a very nice USA-built Fender Strat.

Generally speaking, an adjustable truss rod can be useful to adjust the amount by which string tension bends the neck into an arc but probably won't be of much value in either countering or repairing the tendency of a neck to twist.

Without knowing more and actually seeing your instrument, I tend to agree with the advice of your luthier that attempting a repair may not be the best idea. You might want to explore whether the problems that you are experiencing could be minimized by careful adjustment to the setup.

It wouldn't be surprising if we can all learn something useful from your experience. Your question is an interesting one and may be applicable to some of the instruments that other UU members enjoy playing, so please let us know how you make out and whether you are able to solve this problem to your satisfaction. Good luck!

It’s funny, I was thinking as I read it, “Good thing that will never happen to my Ono,” when you popped in and said why.

 

[merlin666]

I think that the neck of my oldest uke warped a bit last winter. It is kept in a zippered case with soundhole humidifier and it developed some odd buzzing of the g string at some of the higher frets. I figured that the neck was drying out and I placed a damp sponge in Ziploc bag under the neck. After a bit more than a month this seems to have fixed it.

 

[saltytri]

It’s funny, I was thinking as I read it, “Good thing that will never happen to my Ono,” when you popped in and said why.

Well, that's a relief!

 

[greenfrog]

There are two main reasons why necks warp. One is the tension of the strings pulling the neck upwards at the headstock. The other is that some individual pieces of timber have built in stresses which relieve/resolve over time, pulling the neck out of shape. The former tends not to be a problem with the smaller sizes of ukulele. The latter can affect anything made of wood and is quite unpredictable.

You ask some very good questions that focus on what might be done after the horse is already out of the barn. Without, I hope, being seen as minimizing your problem or hijacking your thread, this seems like a good place to remind us all of proper building practices that can minimize problems with a neck down the line.

Thank you both for this!!!

So this wasn’t something I caused? I was feeling so guilty about having it shipped in the summer heat instead of waiting…

 

[greenfrog]

Although not all builders advocate the use of carbon fiber reinforcement, I now use two 1/4 inch rods placed side-by-side down the center of the neck to inhibit changes over time. I don't have any direct experience with fixing a twisted neck but have read that people in the guitar world have had some success by using various methods to mechanically apply counter-twist over an extended period. In fact, my son-in-law had success with this in correcting twist in the neck of a very nice USA-built Fender Strat.

Generally speaking, an adjustable truss rod can be useful to adjust the amount by which string tension bends the neck into an arc but probably won't be of much value in either countering or repairing the tendency of a neck to twist.

That’s good to know!

So when at some point in the future I buy another baritone, I don’t need to focus on brands that use a truss rod? Or assume that baritones without a truss rod will have a more limited life expectancy?

Without knowing more and actually seeing your instrument, I tend to agree with the advice of your luthier that attempting a repair may not be the best idea. You might want to explore whether the problems that you are experiencing could be minimized by careful adjustment to the setup.

It wouldn't be surprising if we can all learn something useful from your experience. Your question is an interesting one and may be applicable to some of the instruments that other UU members enjoy playing, so please let us know how you make out and whether you are able to solve this problem to your satisfaction. Good luck!

Thank you!

For now the solution is “keep the action high at the saddle end” and eventually a new ukulele.

But I’m kind of sad about this one, and have also been worried about buying another and whether it would eventually develop neck problems too, so the new ukulele part of the solution might wait for a while.

 

[bbkobabe]

To be fair, ukuleles that sell for under $200 probably are not made with premium materials... I rather doubt they are aging their woods for years!

I agree with the "solution" that you have suggested: adjust it the best you can and keep playing it..

And then: start saving your money for something better...

Such as a Pono baritone! I simply love mine. I got it used and it is fairly old, but sounds awesome, all for about twice the amount that you will pay to replace what you have.

And yes, it does have a truss rod...

Good luck!

 

[saltytri]

To be fair, ukuleles that sell for under $200 probably are not made with premium materials... I rather doubt they are aging their woods for years!

I agree with the "solution" that you have suggested: adjust it the best you can and keep playing it..

And then: start saving your money for something better...

Such as a Pono baritone! I simply love mine. I got it used and it is fairly old, but sounds awesome, all for about twice the amount that you will pay to replace what you have.

And yes, it does have a truss rod...

Good luck!

I've never used truss rods in my instruments, not that they are a bad idea at all if that's what the builder does with success. I still have a 20" bari that I built about 9 -10 years ago with carbon in the neck, always under string tension, and all is well. The first uke I bought was a base model Pono baritone, all mahogany, about 21" scale, with a truss rod. That was something like 13 years ago. It's been under string tension the whole time and the neck is fine - no adjustment ever needed. The tone is very satisfying. That's real value! If you like a model that Pono offers in your price range, go for it.