National Folkstar resonator neck repair

Date: 03/12/2010

Published in: Gitarist Magazine (nl) 2011

Kord King neck repair

This is an article describing the repair of the neck of my National Folkstar resonator.

The Folkstar resonator

The Folkstar resonator is a special guitar among the resonator guitars. The body is made of fiberglass or reso-glass as it was called when these came out in the beginning of the sixties. What sets these guitars apart is the rather dry sound with a very nasal character, which comes as a result of the fiberglass body.

I had set my mind on getting one of these for a while. Although they do turn up now and then on eBay and some other sites for vintage guitars, I was hesitative buying one that way because I would not be able to see the instrument in real before buying it. I only know if an instrument will eventually work for me when I have it in my hand. Questions about the neck being straight would probably be answered with a yes and even when I was sure about the seller being honest about it, I wouldn’t know if it is straight the way I wanted it to be.

Nevertheless the day came that I could not resist the auction on this black National Folkstar. I saw it on eBay for a reasonable price and I won it for the amount that I wanted to spend. Or maybe I should put it this way: for the amount that I thought I could take a risk.

I was very pleased when the guitar arrived. It was well packed in an, almost new, case and it was in good condition. When I started to play, I knew right away that this was going to be an instrument for me. Originally I intended to find one to use for slide. But when I started playing on the instrument I realized that it would be great for both regular playing and for slide!!

But, as it turned out, the curve in the neck was not right for regular playing. It had too much curve to keep it well in tune and to find the right string height that would facilitate both regular and slide playing. That is when my journey started.

I took the guitar to my guitar tech’ Chris Teerlink of Luthier's Gitaren in 's-Hertohenbosch. Chris has been working on my guitars for more then 20 years now. Being one of the most asked for in the Netherlands, he has a huge knowledge on guitar repair.

Because the Folkstar neck did not have an adjustable truss rod, Chris treated the neck by heating the fretboard. This is the traditional way for necks like this. In this way he could re-glue the fretboard and in the same time bend the neck in the right position. This turned out really well. The neck was in exactly the right curve and I found out that this was also exactly how I would be able to use it the way I intended to.

Unfortunately after two weeks the neck returned to his old position. At that point the only option seemed to be to put a truss rod in the neck. This would be a rather expensive procedure with no guarantee of solving the problem for good. What was so different about that neck?

This neck is connected to the body with a two screw system (and tilt adjustment), a system commonly used on these guitars. This makes it difficult to use a regular neck as a replacement. Putting a truss rod in this neck would also mean that this truss rod could not be running through the whole neck, because of the screws at the end. Not an ideal solution. At that point I decided to see if I could find a more affordable solution, e.g. in finding a replacement neck.

Searching for more information I started searching on the web to find out more on that guitar. One of the places where I started looking was the Michael Messer forum of blues guitarist Michael Messer. Here I got some answers very quickly and right on top of the subject. This is what makes the web so great.

Michael Messer himself was the first to respond. He wrote: "Without going into too much detail, I should explain that the most interesting thing about your guitar is the neck! It was factory fitted to that guitar and was never marketed as anything special. In fact it was never listed in any catalogue with that 1950s National tulip headstock. These guitars were manufactured at a time when (a) nobody cared, and (b) lots of bits were used to make up orders. It is a long story, but Folk Star, Airline and Bluegrass 33 guitars have an interesting and confusing history.

So, my point here is that to replace your neck with any Supro/National Cord King neck would not be easy, in fact better to buy another guitar! However, apart from Jeff Lang in Australia and one or two others, the neck on your guitar is almost unique. Bearing that in mind I would recommend trying to get it repaired. I know you have had your guitar tech' look at it, but I do not think a regular luthier with no experience of these neck would be able to do anything. I will ask my friend Mike Lewis (Fine Resophonic Guitars) in Paris, if he can do anything and let you know. Mike is in my opinion the world's leading maker and restorer of National & Dobro type instruments".

Then Mark Makin, guitarist, graphic designer, and one of the world's leading authorities on all things 'National Musical Instruments' related responded: "Are you aware what a 'Kord King' neck is? The entire neck is an aluminium core wrapped in a thin covering of wood! It was invented and designed to be 'warp-proof'. If you have a bent one of these - it will need some serious work to flatten it - I suspect it may need more than a truss rod. Here is a 1965 Catalogue for the Supro Folkstar which mentions the Kord King neck. Black was more usually used for the Resoglas Airline instrument. The neck you have was a 1950s style used on things like National New Yorkers. The first heel-less necks with a solid core were called 'Stylist' necks. They were first used in 1948. By 1957, they were known as 'Kord-King' necks. They used what National referred to as 'Aircraft technology' i.e. airframe aluminum. This seems to have stemmed from Valcos involvement in aircraft manufacture during the war years.

The headstock style on your reso guitar is extremely rare. More usually, the Folkstar had the typical wavy Supro headstock, the black Airline had the a-symmetrical wavy sided headstock and the National Bluegrass (white version) had the typical National 'Glenwood' type. Yours only occurs on a few select instruments. I suspect your guitar is the Airline version because Jeff Lang (Australian slide guitarist) also has the same neck as yours and his carries an Airline logo. If I were you - I would try to rescue it, rather than replace it." You can imagine I was very pleased to get this expert help and so fast. And above all, the new information made the whole quest even more interesting.
Michael Messer even took time to talk with Mike Lewis. A luthier based in Paris, France and a specialist in National guitars. Michael wrote: "I have just had a conversation with Mike Lewis about your guitar neck. He says that it is not possible to straighten the aluminum rod as it could break the back of the neck. His only suggestion is that you have a new fretboard fitted that is shaped to compensate for the bowed neck. Mike also thought that it has not bowed, but was probably never straight."

I got the feeling that this might be what I would end up with.

In the meantime I had been in contact with Bruce Bennett from BML in Chatanooga, USA, who is a specialist in these guitars. With BML they do the remakes of the Supro guitars. (I found him through a post on this subject on the web.) Bruce said that he could make me a replacement neck. He has done that before, and based his necks on the truss bar of old necks. He also repairs necks that are not broken. "At present I don't as yet, have a suitable supplier for the original Kord King truss bars, so I've been reusing the ones in old necks."

But he also said: "It is also possible to straighten an original intact neck. My replacement necks have been for folks that have a "beyond repair" broken headstock. Most unbroken necks are repairable, they simply require heat treatments and fretwork to solve their problems. Some necks require only 1 or 2 heat treatments, while others require up to 7 treatments and then a complete planing of the fretboard and new frets and nut. The truss bar is glued in the neck with an old epoxy-like glue. The fretboard is glued with that same glue. Over time it becomes brittle and the whole thing comes loose".

I thought then that it would be best to ask the guys at the Michael Messer board their opinion on this again.
Mark Makin responded within a day: "When I said the neck was very rare, I don't mean to imply that the instrument is a 'must-save', exceptionally valuable item. It is certainly more interesting than usual but that's about it!
Please think about the effort and cost implication. With the money invested in repairs you may quite easily find a replacement instrument. After all, there were many thousands of these instruments and they are highly regarded by collectors but less-so by players. As I mentioned earlier on in this thread, the Kord King neck started life as the 'Stylist' neck. It was first used in late 1948 and practically ALL Valco products made through the 50s and 60s with a Spanish guitar neck had them fitted.
Valcos description of these necks was as follows: “In 1949 for the Stylist neck: Scientifically designed featherweight metal ribbed core alone will withstand all of the string tension. The durable wood shell is used merely to make the neck pleasing to the eye and 'warm' to the touch. Compensation against bowing, warping and twisting is unnecessary as these disadvantages do not occur"
In 1958 for the 'Kord King neck: "String tension will not bow, twist or warp this exclusive neck. It is slim, straight and comfortable. The featherweight core is of modern aircraft metal. This improves tone, has no heel and is fully guaranteed" The selling point (as far as guitar marketing was concerned) was not really its straightness but the fact that it did not need a heel to impede the access to higher frets. The actual metal bar in the neck has a right-angled plate bending down at the bottom end (in place of the heel). It is this plate, that is covered by a white plastic sheet, where the heel should be on all 50s Valco solids and archtops. The other end has the bar extending at a 15 degree backwards angle INSIDE the headstock. The idea of course, was to make a completely stable unit of the neck assembly. As we know, it didn't always work. I suppose you can bend anything if you try hard enough!"

So that was an enormous amount of extra information. Who would have thought that? He also came up with a picture showing the internal trussbar. This is not the neck of my guitar by the way.

But Mark Makin also wrote: "Thought you should know that I was round at Dave Kings' guitar workshop a few days back, and he had one of those guitars on his workbench. I'm pretty sure he said he was sorting out a similar problem. Give him a call, he's a great bloke and I'm sure he'd be of help (not forgetting of course that in the UK, he's considered by the elite sliders to be Mr. National)."
So that is what I did. I phoned Dave King In England who called me back the same day. He said he would be able to repair the neck as it is. He was not able to do it soon, but I could send him the neck in a couple of weeks.
Back to the repair shop At that point the guitar was still at the shop of Chris Teerlink. I went down to ‘s-Hertogenbosch where his store is located, and told him what I found out. I also showed him the pictures. With this new information, Chris' conclusion was that he could probably do the repair himself.
When the guitar was at his shop, he found out that the fretboard had come loose from the neck, due to the glue becoming so brittle. Chris said that he could probably remove the fretboard now, even without heating it. By doing this we would be able to see how to proceed. So he did and we then saw a neck with, indeed, a huge aluminum trussbar. Re-gluing the fretboard wasn’t an option, as the neck would probably go back to its old position. It was just too flexible. Chris suggested finding someone who could cut a slot the neck for an adjustable trussrod. This person should then be able to cut in the aluminum bar. I have a very good friend, a former acoustical engineer but now a visual artist, called Michiel van Overbeek. It took a while before I realized that he works a lot with all kinds of metals and that he might have the right machinery. I talked to Michiel who said that he thought he could do it with a CNC machine, a computer controlled router.
So some time later we spent a day at his workshop working on the neck. Most time was needed for preparation. First we had to find out how the neck could be put in a stable position so the cutter could do its job.

We managed to fix the neck by using one of the attachment holes to screw the neck down on the CNC 's table and on the top of the neck we attached two pieces of wood on each side for the same reason.

After we were finished with that we programmed the CNC machine to cut in two lines, side by side, a slot of 6mm wide and eventually 9mm deep. This took the whole afternoon, because we cut it in series of 0,10 mm at a time. It was quite a puzzle. We had to be sure that the slot was big enough to hold the trussrod, but at the same time we shouldn’t cut too deep. Luckily you can work step by step with a CNC machine. The slot we made did not cover the whole neck. Chris had suggested making the slot go up to about 5mm from the first attachment holes. We needed to keep those, as they are an important part of how this neck is attached. But Chris was convinced that it would be no problem to do it like that, because the rest of the aluminum trussbar, in combination with the new trussrod, would be stable enough to make the neck adjustable, yet steady.

After this afternoon I took the neck to Chris again, to have him install the trussrod and to reattach the fretboard. Chris told me that in order to add the trussrod, he only had to make minor extra adjustments to the slot we made with the CNC machine. He removed all the old glue that was left on the trussbar and on the fretboard, before re-gluing the fretboard with two-component glue. He had to use quite a lot of glue to fill the space left after removing the original glue, but that also gave the fretboard the possibility to "settle" in the glue on the neck. He let it dry for about a week to be sure that all the glue had dried, using a special clam that evenly spread the pressure over the fretboard. He then only needed to remove the excess glue and correct some minor marks in the neck paint with black shellac. The neck has now an adjustable trussrod that enables me to adjust the neck exactly to my playing needs. The only visible change is the trussrod cover that was not there before.

Was it worth all this trouble? Mark Makin was very right in questioning how much you should invest in an instrument that, although old and rare, was originally not very valuable. So was this worth it? For me it certainly was. I am a performing and recording musician. My instruments are my tools and however rare or valuable they may be, I should be able to use them. This guitar is an important asset to my collection of instruments, that I am using a lot now and will be using a lot in the future because it is playable. Chris Teerlink was very surprised as well with the result. He said he is sometimes skeptical about reviving vintage instruments that originally where not the greatest instruments. In this case however, with all the knowledge gathered and the chosen strategy based upon that knowledge, we were able to create a solution that made a uniquely sounding instrument be very playable again. That was certainly worth the trouble.

I wrote this article to describe how I solved the problems with my resonator guitar. I have been helped a lot by several people and I hope that this article may one day help someone with a similar problem.

A lot of thanks to Michiel van Overbeek and of course most of all to Chris Teerlink for doing a great job. If you are ever running into a similar problem then contact Chris, as I am sure he will be able to help. I would also like to thank all those who helped me in finding the right information: Michael Messer (what a great board you have!!), Mark Makin, Bruce Bennet and Dave King. Thanks to Ineke van Doorn for editting the article.

(c) 2010 Marc van Vugt

Luthier's Guitars.

Michael Messer

Michiel van Overbeek/Kristalhelder

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