Heat treating a neck?

[T-Bird]

Hi.

Since the magic heat treating necks to remedy crappy workmanship seems to pop up quite frequently, there's a question I'd like to ask.

Is there many people around that can say it really works?

And by working, I do NOT mean that it was enough to fool an ignorant buyer, I mean the instrument to remain playable and adjustable for more than 2 or 3 years without heat treating the neck all over again.


The reason I'm asking is that it was the big craze in "the crap invasion from the east" in the mid 80's, and because it really didn't work, it was pretty much abandoned.
The science also pretty much works against it working so it's not a big surprise. To me at least.

I entered the scene at that time so I have no idea whether that was the first time the method was around (probably not), and since I was pretty inactive from mid 90's to mid 00's as well, I didn't notice its resurrection even if there was one.

And before anyone asks, yes, I did try that with several different methods, and 1 year was the best I ever got out of it. The method that yielded the best results required heat severe enough to soften most finishes and glues.


Regards
Sam

[OldogNewTrick]

No, I haven't had a neck heat treated - so no vote in the poll.

However, I fail to see how that would actually work.... a google search revealed ony warpedneck.com who offer no information except for the promise of a miracle cure....

The billet, from which the neck was machined, could have been incorrectly cured resulting in bowed wood, or may have been inconsitently cured (wet spots) or had a too high moisture level when machining.

With the neck machined straight under those conditions, the possible resultant bend after drying or due to unsuitable grain structure seems to be, from my understanding, incureable.

Maybe you could provide a link explaining the process and underlying theory of the treatment.

[T-Bird]

Hi.

I have no links as the engineer and woodworker in me doesn't see how it would work, so I've been dismissing the idea for years. Up until recently, when the mentions of heat treatment has surfaced everywhere. I may look some up when I have more time, but I seriously doubt that they'll make a believer out of me.

The procedure is really simple, You stress the neck onto the desired shape, and heat it for a pre-determined period of time.

Since neither the stress, nor the heat involved is high enough to cause permanent structural changes in the material (needed for it to work as claimed), a hunt for any success stories is the reason behind this thread.

I'm not saying that it doesn't work because the theory (none) escapes me or because it didn't work for me.

That said, back in the day when I discussed about the procedure with a veteran woodworker, he laughed and told that I'm free to try, but shouldn't expect a success.

Regards
Sam

[john grey]

If grain structure is inappropriate for a straight neck (poorly worked at point of mfg) I don't see how utilizing a method of making it temporarily more pliable would substitute for the improper grain structure. You still have the poorly cut sample.

However, when making walking-canes, there are techniques to bend wood in a radical curvature from a straight sample. I believe that is where the concept may have began. Grain in a single type of wood (example; maple) could be altered but that's a far cry from a laminated neck!
Realistically in that example one is working from straight to curved; not curved to straight. Further, the exacting tolerances do not need to be maintained or even achieved beyond a steep curve (a cane handle is a cane handle; not a musical instrument). In fact if one were to look deeper into that sort of wood working the utility of that technique upon a laminated sample would demand too many complications to stand-up for any period beyond a short span of time. Obviously; only opinion & I know I'm using extreme examples. But the need is for very exacting alterations. I don't see how it would retain straightness if the sample is substantially mis-cut.

[BigOldHarry]

I friend of mine who is a very respected local tech/luthier has done this and it has worked - but it told it it's hit & miss. some necks can be saved, some can not.

[OldogNewTrick]

bending is a fairly old woodworking technology, some species work very well (beech) and others not. However the timber has to be steamed inorder to make it pliable and is then dried in form/shape.

Not at all the same thing.

Just using heat, like using an iron for pressing a shirt.... hmmm, I am always interested to learn something new... I especially look forward to any explanation as to what happens to the cell structure of the wood.

Edit: Heating up a neck will dry the timber out beyond the ambient temperature moisture content equilibrium point. The timber will dry at uneven speed (end grain, tangential and radial grain) causing even more bending problems. Maybe there is a crucial part of the process not mentioned so far.

[Hoover]

I've had two different bass necks heat-straightened by luthier Craig Jones @ New England Vintage Guitars up in Boston MA. The work was performed sometime between 1993 and 1996. One of those basses -- an 8-string (!) with a 3-piece laminated maple neck -- was still straight when I sold it 10 years later. The other bass -- a 4-string with a 1-piece bird's-eye maple neck -- is still my main go-to bass and is still as straight as it was when Craig fixed it ~15-17 years ago.

[Ben B]

my case may be a little different than what the OP is referring to. My bass is one of Carvin's early 5 strings and I believe an inadequate truss rod was the cause of the problem rather than an issue of poor quality wood or poorly cut wood. I believe within the next year or two, Carvin started using reinforcing rods to eliminate this problem.

Anyway, I purchased a Carvin bass new in 1989. After I had it a couple days, the neck bowed due to string pressure. I tightened the truss rod and it was fixed--for a day day or 2. Then it bowed again. After a few days of the bow returning and adjusting the truss rod, I had the truss rod tightened all the way and the neck was still bowed.

I sent the bass back to Carvin and they heat bent the neck. It worked. The bass has been fine ever since--22 years later.

I will also add that heat bending is part of Taylor's normal production process. I haven't heard of any of their guitar bodies warping after assembly.

Ben

[OldogNewTrick]

there is no mention of such a process on the Taylor Guitar website....

Can anybody point me to an explanation on the process?

[john grey]

Originally Posted by Ben B

my case may be a little different than what the OP is referring to. My bass is one of Carvin's early 5 strings and I believe an inadequate truss rod was the cause of the problem rather than an issue of poor quality wood or poorly cut wood........

I think this is a primary issue. IF the elemental neck is well made, there may be every possibility of achieving a slight correction through various techniques.

However, if you're starting out with a major mis-shapen lamination (or even solid sample) it seems too demanding to maintain.

[Ben B]

Originally Posted by OldogNewTrick

there is no mention of such a process on the Taylor Guitar website....

Can anybody point me to an explanation on the process?

I live about 5 miles from the factory. I took a tour and saw the process. I can't offer much explanation except it's a machine with clamps, rollers, and a heat source that reminds me of a fuser in laser printers. I don't believe the machine adds moisture, but Taylor's keeps all wood in a humidity controlled environment, so, I'm sure the wood is already at the right moisture content to do the heat bending.

'If you even make it to San Diego, you can take a free tour of the Taylor factory.

Ben

[lavmonga]

Had a 1980 Koa winged Maple neck thru BC Rich Mockingbird, truss was turned completely. I needed heat treatment and it lasted about 6-8 months before it needed it again, I was touring at that point though and going through some drastic weather conditions.

[Hapa]

I build basses for a living. I have done repairs using a heat treating method and it works. Most simply don't do it correctly, mainly leaving the heat on the neck for too long and then unclamping too early. Or in instances where there is not a truss rod or a cheap truss rod or a rod that has been forcibly bent out of effectiveness nothing can really straiten out the neck. Also keeping in mind an unstable neck is almost always forever an unstable neck. If it ever got so far out of whack that it even needed a heat treatment, why is the player even considering relying on it?

I am reading above and I think yall have the wrong idea about what heat treating is all about. Its not at all about bending the wood back into shape its resetting the glue.
The glue is heated and softened usually with a heating element and flat metal block with dots/blocks covered to prevent burning/ scorching (fixing an upbow) and with the truss rod neutral. When heated it should be clamped to a back bow (slightly...by experience) meaning the body of the guitar needs to be set in a jig. unless one has a string tension simulation jig with a fitting for that type of neck. the fb clamped to a flat heating block with remain parallel in radius to the back bowed neck. like clamping a finger board to a backbowed neck from the start like classical guitar builders used to do before truss rods existed but after the fact.

Doing this can cause many other problems with the neck after the fact as well. If you are applying enough heat to loosen glue on the neck the same applies to Frets, they can easily come loose. Dots and blocks can easily be damaged or binding, ivoroid binding can go into full combustion. pearloid same thing anything cellulose based really. Its not a strait ahead repair and results are not always what you want. Most guys won't do it because of all the other stuff that can happen not that it doesn't work.

[blindrabbit]

I had a heat treatment done to the neck of my Guild B-50 back in the early 90s. The neck was warped something nasty. Anyway, it didn't work worth a hoot, and I ended up selling the bass shortly after. The luthier was a pretty decent guy, and seemed to know what he was doing with other repairs, so I'm more likely to fault the treatment as opposed to the quality of his work.

[T-Bird]

Hi.

Thanks guys, much appreciated.

Heat treating, bending and lamination using steam & pressure are ancient woodworking methods I know, but mainly in manufacturing, not something that can be used on a finished instrument. Without a neck refin that is.

I've steam bent wood obviously, as well as have I made a test lamination in the "Alvar Aalto" style, but then again so has probably every woodworker in Finland .

I'm also well aware how the "band-aid" method could be used on a hack build to make a quick buck, hell, if the mistake isn't severe enough it may even work for quite a while. Not long enough for me though, as Hapa among others have said: "an unstable neck is almost always forever an unstable neck" . I have never sen anyone who has done extensive repairs to disagree on that.

One of the necks I treated all these years ago was my own work, and since it was unfinished, it also held up the longest.

Still, I'm not entirely convinced that the method is as feasible as the folks praise it for (and suggest to using it to left and right), to me it seems like a quite a bit of work for unpredictable results. And since the non-destructive repair is mostly a dream only if lasting results are expected, the valuable neck that could have been saved with a more suitable method may well be ruined beyond feasible repair.

Since the tools and facilities are much better nowadays, wouldn't a simple FB reshaping or removing the FB (/skunk stripe) and replacing the TR with a double acting rod be more cost effective in the long run?
If "in the long run" is the repair persons and the owners intention .

Regards
Sam

[JLS]

It's always worked, for me.

When thewood of the neck has taken a set, you have to un-set it. I'm unconvinced that it's solely the slipping of the glue joint.

[Hoover]

Originally Posted by JLS

I'm unconvinced that it's solely the slipping of the glue joint.

Since I've had it work on a 1-piece neck I'm inclined to agree.

[teleharmonium]

I don't think there's anything wrong with the science of it; but not all wood will respond to it. Maple is special because after heating, it tends to retain the new shape. That's how lots of instruments are made in the first place; you heat up laminated maple and bend it into a mold and now you have the curved sides or the arched top or back of a hollowbody guitar.

I don't know what other woods allow this or how well they all work, but presumably all of the woods normally used for the sides of acoustic guitars would allow this, since they are steamed and bent rather than carved out of larger solid pieces. Solid mahogany and rosewood, laminated spruce certainly. But they may not handle it being done a second/+ time as well as maple does.

[Hapa]

Originally Posted by Hoover

Since I've had it work on a 1-piece neck I'm inclined to agree.

Hmmm, It worked on a one piece? now I got to think a bit about that. So I will agree may not only be the glue joint, other than that I am stumped. Not to be un-trusting, but was the one-piece fender style with a truss rod or like a musicman one-piece where the fingerboard is cut from the same blank as the neck making it appear as a one. The only thing I can think of is resetting the skunk stripe glue but that doesn't seem like nearly enough wood to re torque the neck. this is going to bother me...

[BassmanAd]

Just out of interest (I've never experienced a neck warped so badly it needs treatment) what kind of conditions cause this? Is it just a case of a badly cut neck blank or can it be caused by extreme ambient temperatures / humidity? I've done a lot of international touring with a late 70's P-Bass with a one piece maple neck, including many flights, and I did find myself tweaking the truss rod more often than any other basses but the neck always straightened out and never warped.