CAN YOU RE-SET A YAMAHA ACOUSTIC GUITAR NECK?

CAN YOU RE-SET A YAMAHA ACOUSTIC GUITAR NECK?

By Brian Howard, luthier

  Yamaha guitars have a loyal following and have always been a good value for the money. A common situation is that someone comes into an older Yamaha acoustic that has seen its best playing years. And as is typical of older acoustic guitars they often need a neck re-set to compensate for the deformation caused by years of string tension trying to fold the guitar in half.  So this becomes a common request. And while some makers like Martin make the job quite easy for the serviceman others like Gibson make it tougher and then some are all but impossible…… Yamaha acoustics will fall into the latter two categories, tougher and impossible.

  So how can you tell which you have? There are a few ways to tell. Older guitars built for the USA export market that have the inside of the sound box finished are generally set with a releasable glue and aside from the fact that they are finished after joining like a Gibson come apart rather easily. These instruments appear to built entirely with a white instrument glue similar to the old LMI product. The finish inside was only done on export guitars to keep moisture damage from sea shipping to a minimum. So guitars that were built for the eastern “domestic” market will not typically have finish inside. Lots of guitars have migrated around the world especially in the digital age so interior finish is only one clue. Here are some pics of the finish inside a 1972 FG160

  If the instrument is unfinished on the inside that does not necessarily mean that it is now one of the impossible or nearly so types….. They also switched to water resistant glue for main assembly to eliminate the interior finish which was expensive and spotty at best but retained the former releasable glue for the neck joint. As it is completely sealed by finish this was fine. At some point, maybe when the truss adjustment was moved to the body(?),they started using this same glue for the neck as well. This is where the problem for a conventional neck re-set comes in.

  The problem with releasing water resistant glue is that it is water resistant and therefore steam resistant. Making it a real problem to get the dovetail apart as all the adhesive must be heated to about 250 °F to release.  By the time you get the joint itself up to temp long enough to release a lot of other parts will start coming undone as well. These guitars are candidates for bolt on conversions of their necks only.

  So, the only way to know for absolute certain on any guitar of unknown construction as to whether it can have a conventional neck re-set or should be converted to a bolt on is to release the fret board extension on the body. The glue used under the extension will be the same glue used in the entire joint. So if the extension comes loose easily and cleanly the joint will respond well to steam and conventional methods of re-setting a neck. If however this is hard to release at reasonable temperatures, if your pallet knife is coming out of the hot joint with sticky residue all over it then this should be a conversion job. And since this is the first step for either job you do not to dig in too far to figure out which path to follow.

  Since I have one here I decided to demonstrate the neck removal process. First I score the finish all around the joint with a razor and protect the top and pick guard with my heat shields. Then I place my iron set on high on top of the FB extension, be careful not to toast the position marker dot!

  After about 7 minutes or so you should start smelling rosewood..... When the FB starts to sweat oil like this pic it is ready. The difficultly you experience here will be what the dovetail holds in store.... also shown, my selection of knives for this type job.

  Now work proceeds as normal, while still hot I pull the 14th fret and drill two access holes. Install the neck removal press and steam the joint. About 10 minutes and it's all undone.

  We now know the if and the how….. but let’s talk about the different approaches and their results and approximate costs involved in each. The conventional re-set is the traditional way to go but is in the same labor/cost class as a Gibson or Guild guitar and will involve separating and dealing with finish. So this generally costs about 30% more than a typical Martin re-set job. With fret level and crown, new saddle and finish work you are about 9-10 hours on an invoice here plus parts. On the other hand a bolt on conversion can save a bit on that and would bill at 6-7 hours plus parts.

  In the end there should be no real difference in feel or sound between the two jobs assuming both were done very properly. In fact the conversion is almost always an option on any guitar if costs are the main concern. Since we are now discussing costs I would be remiss if I didn’t point out that on today’s market few Yamaha acoustics have retail values high enough to warrant this type of investment unless for sentimental reasons. But they make fine instruments for learning Luthiers to practice on as they are reasonably well built, decent sounding and affordably priced on the used market. Look for a complete bolt on conversion neck tutorial in the near future.

  Brian Howard, Luthier

  Magnolia, DE