Glue used on a 1960's Japanese? archtop

[blackalex1952]

I am working on a restoring what I believe is a 1960's Japanese made archtop guitar. The instrument has some curious attributes. All plywood construction, the veneers are all two ply, Maple outer. The bracing is similar to the bracing on a French Italian f hole guitar,eg a Castellucia, being ladder braced with two angled longitudinal braces under the bridge which connect to the two lower ladder braces. The neck is attached so that the fingerboard contacts the soundboard, unlike the Benedetto/Gibson construction. The binding has a distinct decorative inlay, which appears to be MOP with some kind of black paint infill. The inner bindings are a single 2mm thick solid Spruce. The lower top and bottom brace ends are linked at the brace ends by uprights, which at first glance look like side splints, but are only glued to the inside of the liners and do not touch the laminated sides. Pix attached. Comments re Japanese origin or not, please?
Because the braces were rattling I decided to pop the back off, which came off cold fairly easily with a knife, the glue was quite brittle. The brace "props" were unglued where they were glued to the ends of the back braces by pushing a knife blade in from each f hole. I was able to remove the back without removing the plastic binding. The brace ends were a little more tricky where they were let in to the sides, but I managed. The glue didn't respond well to heat. At first I thought it was hide glue of some sort, but now I am cleaning the old glue off the tail and headblocks in order to ensure that my hide glue takes, I am finding that it has the following properties. I don't believe, by the way, that is is an epoxy. It has penetrated the end grain of both blocks, one is Cedar and the other is a hardwood of some sort. It is very hard and doesn't sand well, it also blunts tools. The best method ended up being a coarse file. I took the glue shavings and dust and held them on a knife over a flame. It didn't smell much, definitely not like a plastic or resin, and didn't melt or fuse into itself. It also did not easily come off the end block when I tried the hot knife. When I removed braces and cracked the back it was brittle. I am wondering if anyone knows what kind of glue may have been used, I suspected Casein, but not sure. The dried colour is like a very light hide glue. I have not had any experience with fish glues, knowing the Japanese love of seafood, I wouldn't be surprised if it was made from whales! The repairs have gone well, the guitar had been poorly repaired by gluing two huge maple splints on to the sides of the rattling longitudinal braces, via the f holes. The glue hadn't taken properly and the braces still would have rattled due to the fact that the glue between them and the top had failed. So they ended up being twice as stiff. Other braces were also unstuck. The owner said that the guitar, last time it was strung up, was quiet, but he liked the sound, except for the rattling. Being plywood, I haven't liked my chances, but decided to do some brace shaving having stiffness tested the top for flexibility, and removed the extra unneeded Maple stiffening. So I am very curious about the glue!

[kiwigeo]

What makes you think it's Japanese? Most Japanese guitars Ive seen from the 60's have generally come from a fairly small number of known manufacturers (Suzuki, Yamaha etc) and there'd generally be some sort of ID mark or number somewhere on the guitar.

[kiwigeo]

Being plywood, I haven't liked my chances, but decided to do some brace shaving having stiffness tested the top for flexibility, and removed the extra unneeded Maple stiffening. So I am very curious about the glue!

I reckon you could probably remove the braces completely and not affect the sound or strutural integrity of the top

[blackalex1952]

I reckon you could probably remove the braces completely and not affect the sound or strutural integrity of the top

HA HA! Well, the plywood was rather thin, and when I removed the longitudinal braces it flexed quite a lot, even though the ladder braces were still way too stiff. It is a very lightly built guitar.I did a deflection test with my rig and a 3kg weight and the section where those small braces were was quite flexible, but over the lower ladder brace there was stuff all movement, so lowering that brace height,I figure, is probably a good thing anyway, so that the guitar has a chance of having better bass as the lower bout would move more. I aimed at getting the top to move, at least below the centre brace, as one unit. I also took a little off the centre brace, but left the neck brace as it was to keep the neck angle stable. Although the top was just two ply, with what looked like Meranti on the inside, the Meranti was about twice as thick as the Maple. I also thinned the inside ply on the top around the lower edges just inside the liners. I had an old classical, the first guitar I owned over 50 years ago, and sanded it back to re finish later when I was a teenager-I had sanded the edges thinner (don't ask how I know this) and noticed a marked improvement in tone and volume. This got me interested in guitar making, way back then, but have only, relatively recently for my age, been actually making. (I have done my share of repairs over the years for my students as a guitar teacher), and have always done my own set ups as a guitar player.
I did some google image searches, and found a guitar with strikingly similar binding inlay. It was made in Japan by a factory which was run by a guy who had been one of the first Japanese manufacturers after WW11. There were Canadian and US companies that re labelled Jap guitars for their markets, and used multiple names. The name Canora, well known in Aus in the 60's, is the name of a place in Canada..they labelled Jap made guitars for distribution. The thing that makes me a little unsure re the origin, is the bracing...a definite French Italian influence there. But who knows what was going on in Japan post WW11..major change and European/American influences. The liner method is questionable, also the quirky props at the ends of the brace...I reckon the props help with the strength given that the liners are so light. So I posted all that info in the hope that someone could tell me the guitars origin. The owner said that he had a vague memory that it was made in Japan. I think he sanded the logo off when it was re varnished at one time. He is an accordion player, so one could forgive a poor memory!
https://drowninginguitars.com/2015/06/0 ... op-guitar/

[jeffhigh]

A customer of mine has a friend in Japan who sends him guitars for resale on Ebay Australia.
A while back he brought me a couple of archtops, one of which looked very much like yours with the wide binding, but with the original dark finish.

It was a horrible guitar, bad neck angle,huge non adjustable neck, nasty tuners etc and the sound was poor.
I am sure that the attention you are giving this one will improve it.

The Japanese guitars I have seen from the 50's and early 60's seem to be mostly GLO's (guitar like objects), built with no real understanding and without the attention to copying details that the Japanese became known for later

[blackalex1952]

Thanks,Jeff. The more info the better. This guitar has had a solid steel truss rod put into it and a nice rosewood fingerboard added by a luthier in Melbourne many years age.So all intonation and neck issues have been dealt with. Tuners stay in tune, according to the owner. He also reports that he likes the sound it made, although quiet. It probably has that ladder braced gypsy jazz sound, or the old bluesy mojo. As I said previously, I decided to try to open it up more with my modifications.I'll see how it goes, but perhaps my efforts have been in vain...I'm pretty sure I will have squeezed a little more out of it.Given that, with all the loose braces, the only way to get it back into shape was to remove the back plate, I thought why not give it a quick go? (I also had to reglue the top to the sides in a few areas) If it is still nothing to write home about, with the plywood construction and the fingerboard flush with the top, a pickup could be fitted into the soundboard. Given the old neck work, it will be a playable guitar and I reckon that, either way,I'll squeeze some usefulness out of it.
But I am still curious regarding the bracing used, there is a definite European influence there I suspect, as I haven't seen any US archtops with that-the ones I have seen have had either parallel or x bracing. And my glue question is still unanswered. Perhaps casein glue? I have never seen dried casein, but believe it's water soluble, hard and stronger than hide glue and dries clear (according to Wikipedia) Cheers! Ross

[Dave M]

There is a glue sold under the brand name of Cascamite in the UK. All I can see is it is described as a 'powdered resin' glue. It is comes as a dry powder which is mixed with water. It was very popular with hobbyists a few year back. Reckoned to be good for external work.

A possibility for your stuff. It is certainly another class of adhesive to the usual suspects.

Dave

[routout]

I agree that powdered stuff was popular back then easy to use I remember making a small dingy with the same type of stuff