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"Economy" Chinese Instruments Finish and Glue


Bob Sp
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I am faced with repairing less expensive Chinese instruments (okay - maybe cheap is the right word).  I am suspicious I am dealing with something other than hide glue and real varnish.  Does anybody know for sure?

 

I have gone through a couple of dozen threads in the Pegbox to see if there has been any mention of what kind of glue and finish are being used on Chinese instruments currently being produced.  I haven't found any mention of this.

 

I am reluctant to experiment on somebody else's violin, so I am asking here if anybody knows.  I am suspicious that the finish may be some kind of commercial spray lacquer - at least on some (some are very brittle).  I am seeing mostly Gewa and Menzel brands around here.

 

Cheers,

Bob

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If you have an older Parrot or similar Chinese from 1960/1980 or more recent better one, I'd say that you can expect animal glue. With new cheap Chineses, you can expect anything (hide, white, yellow, PU, epoxy...). Try to look into the body and find some glue squeezed out of joints. It could give you some idea about the sort of the glue.

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I have looked inside a few and there is usually a white powder residue.. I thought at first it might be glue residue but I now believe it is buffing compound used in polishing a lacquer finish.

 

I have seen what might be a transluscent glue.  I am considering finding one to sacrifice and deconstruct it.

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IMHO, the commercial Chinese finishes I've seen aren't varnish as we know it, but some polyurethane or nitrocellulose spray finish that is nearly impossible to touch up if it chips or cracks.  It's hard and it's pretty, but it seems insoluble in alcohol, turpentine, etc. and so doesn't play nice with real varnishes, shellac, or acrylics1:huh:

 

 

 

1.  In desperation I tried to repair a patch of it with clear nail polish once.  Looked good at first, then separated later.  And, no, I don't have any poly or nitro lacquer in the shop.  One might try those..... :rolleyes:

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Nitrocellulose is easy to retouch. Poly is impossible.

 

Most guitar manufacturers who use the catalysed Poly suggest CA for finish repairs.

 

With the cheapest Chinese stuff, I try to scratch the finish or glue with a knife, scraping some finish/glue off and smell of it. You'll figure out what it is most of the time.

 

I almost always try hide glue first, and if it doesn't hold, move forward from there...

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I had to repair an inexpensive Chinese cello which had a detached fingerboard. The residual glue on the neck and f/b was VERY easy to dissolve with warm water. The softened glue smelled exactly like wheat paste which used to be used to hang wallpaper.

Perhaps rice starch paste (a bit stronger than the wheat paste) cooked with some sugar and rice vinegar? Rather usable glue, as far as I know.

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I mentioned that glue made from rice flour and starch because I have some experience with it. During the war in Bosnia, we did not have a lot of things available, among others - glues. But, at times, we have had various kind of flour and some amount of various starches, unsuitable for human consumption, for various reasons. So, we made glues. These "kleisters", when we had some "real" glue to mix with, were almost good for furniture repairs, but for bookbinding - close to excellent.

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Rice glue is the traditional glue for Japanese joinery.  It's just strong enough to hold the joint together, but separates easily with a small tap (much less than for hide glue).  The strength of the join is from the joinery, the glue just stops it slipping during use.

An amusing trait of the rice glue, is that when it has been cooked to the ideal consistency for eating, it is also at the correct state for joinery.

 

I can't imagine using it on violins (or even VSOs), as it has bulk, and cannot be spread thinly in the way that hide glue does.

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I have looked inside a few and there is usually a white powder residue.. I thought at first it might be glue residue but I now believe it is buffing compound used in polishing a lacquer finish.

 

I have seen what might be a transluscent glue.  I am considering finding one to sacrifice and deconstruct it.

If you can put the little piece of Kleenex soaked in hot water over that translucent remain, after an hour or two you will know whether it was hide glue (if it softens) or something else (if not).

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I have looked inside a few and there is usually a white powder residue.. I thought at first it might be glue residue but I now believe it is buffing compound used in polishing a lacquer finish.

 

I have seen what might be a transluscent glue.  I am considering finding one to sacrifice and deconstruct it.

For me, the specks or splatters of white residue on the inside is one of the identifying hallmarks of a less pretentious Chinese violin, and I'd like to know what they are.  

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A lot of the mid cost range commercial instruments coming out of China are top coated with a CNSL based varnish.  This is a natural phenolic liquid made from cashew nut shells.  The varnish is very tough and somewhat brittle.  It powders easily when abraded.  If it scratches it is tough to repair.

on we go,

Joe

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