Sythetic Shamisen body

Building/Repair
#1

Hello everyone, I am new here and seeking some help with a repair. I am a luthier from Canada, mostly building acoustic and classical guitars.

Recently, a client has brought in a shamisen for repair. The instrument needs a re-skinning, simple enough. To my surprise, the instrument’s body is made of a synthetic material, which has a good resemblance to Teflon.

My question to you, is which glue should I use for this type of instrument? I’ve tested white/yellow wood glue, fish glue, hide glue, yellow/white cement glue (PVC), and even epoxy. None of those will adhere to the body properly and the cement glues seems to soften up the area but not adhere. I have not tested rice glue yet, but my guess is if hide glue doesn’t hold, rice won’t hold either.

There is some excess glue on the inside from the original gluing of the skins, which is yellow. It is similar to woodworking glue, but my tests have not been positive with wood glue.

So I turn to the forum for help. If anyone has worked on a similar instrument, please share some info.

http://imgur.com/rH6n7Iw
Notice the smudge on the lower left corner. The material has softened up from the cement glue.

Thank you,
Stefano Vellone

#2

Whoa, that’s a crazy dou! Personally never seen anything like this. I’d PM Kyle about it; he’s the man to go to for all kinds of questions like this one.

Best luck with the re-skin~!!

#3

Yeowzer! I haven’t seen a dou like that before. I’m gonna send a picture to my friend who skins shamisen and ask him if he’s ever seen a dou like this in his profession.

The outside seems very real. Does is seem like only the inside surfaces are coated with the synthetic material? If so, you could just scrape it off entirely.

If it seems solid, then perhaps… epoxy?

#4

It’s all synthetic, unfortunately.

The outside is etched to make it seem like wood grain and painted that color. The etchings are actually symmetrical on all four sides. No wood used in this, sadly.

The tests with epoxy were not satisfying. It didn’t hold well enough. I used marine grade epoxy, with a 7day cure time.

I’m tempted to use the cement glue, since it held. Only problem with that one is that it softened up the material. Pushing my nail lightly into it left a dent…

#5

すごい! I have never seen a shamisen with this material, looks like a sort of fiberglass or plastic. Have you tried the glue kyle uses to skin his shamisen? Its really strong however i wouldnt know if it was safe to use on this material…

Lets get gary in on this because he is a wizard who collects many shamisen…

#6

I saw some completely synthetic shamisen in a Japanese instrument factory in Nagano some years ago. Their market was public schools, and the goal was to mass produce the cheapest instruments possible. The ones I saw had synthetic skins, which would probably be easier to glue to a synthetic body. Unfortunately, I didn’t see them putting the skins on, so I don’t have any idea what kind of glue they used.
So that’s a roundabout way of saying “beats me”.
One tip, though: skin the back first, wait and see how it goes, then do the front once you are sure it worked. If something goes wrong with the gluing surface on the back, you can always sand it down smooth again, but if you try that on the front you will mess up the action.

#7

Thanks for chipping in, everyone!

I’m only reskinning the back since the client is on a budget. But that is very helpful to know about the action.

I’ll have to give it a go with the cement glue and hope it holds.

#8

頑張って:)

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