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Recently noticed how cleanly and easily I can peel the fishglue dried squeezeout with a sharp chisel of an ebony FB and fearing the glue might have gone bad I decided to test it. Glued offcuts from same neck and FB, 12h later put them in the vise, blow with a *big* hammer, 100% wood failure within the spanish cedar. Then moved the largest piece to the bathroom where i had a bunch of clothing drying up. Stayed there for a couple days, there were always clothing drying and people showering, its wet like a swamp.
Checked up the sample, all squeeze out (a bunch of it) has soften up completely, *could simply wipe it off like a syrup* !
Then put it in the vice, this time the ebony split, and then again, another cedar failure, but the joint remained absolutely intact.

I will probably not bother repeating it for a longer time since Colin already tried that and it seemed to hold.

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Build log

This is really good to know since I use it for almost everything

Great job Alex!!

This is great info to have so thanks for sharing

Alexandru,
I've noticed the same thing with hide glue. Matter of fact, I was just now flaking some dried glue off the sides and top where I had glued the binding on. I had a wash coat of shellac on the wood and was thinking how nice this it that most of the sqeezin's just peel off. I know that the binding is on tight and won't come off unless heated with moisture. Hide glue sands off pretty easy too. That's why I like working with it. I want to try fish glue sometime. I just like how hide glue sets up fast.

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"After forty-nine years of violin building, I have decided that the search for a varnish is similar to the fox hunt. The fun is in the hunt."
Jack Batts Maker and Repairer of Fine Violins

As Todd pointed do, that test doesn't give any information how a joint lasts over time, extreme environments, cyclical changes, etc. Will it cold creep, creep easily under heat or humidity, how's it's sheer strength, impact resistance after going through 100 wet/dry cycles under a load. If you had placed a long board against the end of one of your test boards, then struck that with the mallet (as though slide them apart, parallel force instead of perpendicular) the wood/joint failure may have been much different.

I'm not doubting or criticizing your conclusions. When I started using fish glue it seemed no one else had ever heard of it, and I did some similar simple tests myself. There are just so many variables to account for in the true test of a glue. I've always planned on doing much more involved tests with hundreds of samples, different forces, different glues, controlled environments, etc., but in spite of my intentions have never found the time to make it happen.

My experience shows me fish glue is fine, and will hold up without problems in intermittent periods of high humidity. I have heard some reports of failure in very long term high humidity (bayou conditions), but I see hide glue joints fail in those as well. It's been my main glue bottle around the shop for years and I've no plans to change. I use hide glue quite a bit still in favor of fish glue, largely for it's quick dry time and ease of clean up. It biggest trade off for me seems that the long working time comes with a very long clamping and curing time as well.

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Eschew obfuscation, espouse elucidation.

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I am using the Norland/LeeValley version.
According to Joshua, the German one sets a lot faster (maybe 2h compared to 6)
I remember I did a bridge mockup test rosewood to spruce and i ripped it after only about 1h, the spruce failed for most of it. But I keep every joint clamped for 12h as per bottle instructions just to be sure. I found out that thick stacks of veneers for marquetry might need even 24h to fully harden.
Considering I build part-time and that this part is very limited, the wait is killing me so I am moving to hide glue on my next. I will keep using fish for gluing the back and likely the FB too.

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Build log

I like fish glue and I use it extensively. But I have to say that I did recently have a bridge that was glued with fish glue come loose after a couple of years. This was a first for me. It was a clean separation (95%) and I'm unsure of the circumstances (obviously I am pretty adept in my bridge gluing technique - never even had a repair come loose).

Soon I am beginning a guitar for a member of this forum who is from Singapore. I spoke a bit with Gerhard Oldiges about this a year or so ago. He is the person who introduced Fish Glue to me and to Jose Romanillos. Based on the conversation I had with him and some issues some others have reportedly had with the glue in conditions similar to Singapore (Very humid and hot), I plan to use titebond for most of the guitar.

I trust Fish Glue, but in some circumstances I feel other glues are better suited to the job. I think that when you ask the best and most experienced makers, they will usually tell you that different glues are good for different applications. Mario, for instance, has used several different glues for different applications - and his insights are worth looking at.

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Instagram: @jfrenchluthier
Web: https://www.jfrenchguitars.com/

Also - I prefer the Kremer fish glue to the Lee Valley. I cannot prove it, but they seem very different in use. Piano makers and repairmen use it quite a bit.

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Instagram: @jfrenchluthier
Web: https://www.jfrenchguitars.com/

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In Taiwan, 50% RH is considered quite low and it almost never goes below 40%. Titebond joints held much better than Lee Valley FG here. I've never have a titebond-glued bridge failure OTOH.

Well Mike turned me on to FG last year and i love it for joints wher I need a bit longer open time.

Anyone know which fish glue on the Kremer site is the most applicable to Luthiery?

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

This is the one that I use and love. I glue braces and bridge with HHG and everything else with this FG.

Kremer fish glue

As Alex mentioned I ran some basic test some time ago with Hardwood/Hardwood, Hardwood/Softwood and Softwood/Softwood joints, these lived in our showerroom for a couple of months and must hgave gone through a hundred or so cycles of near 100% humidity, some of the wood distorted and bent, but I could never get a glue joint to fail, the wood always broke first.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Norland!!!