freya
Oud Junkie
Posts: 276
Registered: 2-8-2004
Location: Asheville NC
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Mood: Happy in the mountains of WNC
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Fish Glue
Greetings,
I saw a post on the forum here a few weeks ago referring to "fish glue". I had seen references to "Isinglass" previously but had dismissed them as
being a) esoteric and b) environmentally troubling as the Russian sturgeon is under such stress.
Looking around a bit more I found numerous references to Norland fish glue on various luthier sites and all of the references were positive - not a
single example of actual failure under high humidity conditions. It is made from collagen-bearing parts of deep sea fish like cod and haddock -
basically the scraps.
I got a bottle of glue from Lee Valley and glued up the braces on an oud top and the braces on a jumbo guitar back. I then used the fish glue to
attach the back on the jumbo. I must say I have never used a glue that was easier to use and more forgiving than this fish glue. It has good tack
after very brief expose to air, does not run all over the place like titebond - either on application or as squeeze-out - and stays workable for at
least 15 minutes - far long enough to mess with alignment as still get a good joint. It cleans very easily with a damp cloth (while still in the tacky
state). Also, no smell that I noticed.
We'll have to wait for the weeks of high humidity this Summer to see if it softens at all, but the reports I've seen suggest that will not be a
problem. I've attached some info from Norland on the properties of the glue.
Cheers
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SamirCanada
Moderator
Posts: 3405
Registered: 6-4-2004
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+1
it is great stuff indeed.
@samiroud Instagram
samiroudmaker@gmail.com
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jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
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It should be noted that 'isinglas' is not the same stuff as 'fish glue'.
Isinglas is made from the swim bladders or 'sounds' of fish - most notably the Sturgeon but also other species such as Hake, Cod, Ling, Catfish and
Carp that have well developed sounds that can produce good yields of the pure gelatin (i.e. glue). Isinglas for centuries (according to historical
record from at least the 14th C but probably much earlier) has been used (either alone or mixed with hide glue) as a glue for instrument work and
woodworking in general so has a long successful 'track record' as a wood glue. It is prepared for use, hot, like hide glue.
The wild Sturgeon is now an endangered species according to C.I.T.E.S. so legal supplies of sturgeon isinglas now come from fish farms where the
creatures are raised primarily to supply the market for caviar. The stuff is very expensive - $700 or so a kilogram - but its supply is ensured from
legal sources for those who can afford it.
Better quality fish glue is made from fish skins (like the Lee Valley and Norland products) lower quality stuff is made from any old fish waste. It
comes in various 'strengths' from being suitable only for gluing paper to a much more sustantial glue. I have yet to find any historical reference to
fish glue being used for instrument work (although this type of glue likely also has a long and ancient history) so assume that its use in luthier
circles is a recent innovation - untested for longevity (like most modern synthetic glues).
There would seem to be a mixed reaction among luthiers as to the suitability of fish glue for all aspects of instrument assembly work although - as
with all animal glues - much depends upon how a glue (and joint surface) is prepared and the glue applied. Some luthiers swear by it while others have
experienced catastrophic failures for whatever reason.
Liquid fish glue contains a deodorant chemical to disguise an otherwise (to some) offensive stink as well as an anti-bacterial agent to delay the time
it takes for the glue to eventually go bad. This period (shelf life) for the Lee Valley fish glue is 2 years - although no doubt there is a factor of
safety in there allowing a longer period without spoilage.
Shelf life is not a problem for either hide glue or isinglas as these glues in their solid form will keep indefinitely and are only 'made up' as and
when required.
Of interest would be the unbiased testing of stressed glued joints under elevated humidity levels for liquid fish glue compared to hot hide and
isinglas glues - not an easy matter given the possible variables but worth a try.
I have an interest in testing genuine isinglas, hot hide glue and Lee Valley fish glue as a binder for making silk oud strings but will, at the same
time, arrange to test these glues comparatively to see how they hold up to stress and humidity as wood glues - to be reported (eventually!) as a
separate topic on this forum.
These tests will hopefully supplement Harry's planned investigative work concerning Lee Valley fish glue on this thread.
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jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
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Here for general interest is a paper from the US Bureau of Fisheries dated 1917, concerning the manufacture of isinglas glue and fish glue
http://archive.org/details/fishisinglassglu00whit
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