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A couple months ago, I took some leftover soundboard scraps and used 18 month old fish glue to attach some small Mahogany blocks. I had been meaning to test the glue for a while but just hadn't gotten around to it. The joints were prepped like I normally do -- freshly sanded, clean compressed air to clean off all the dust, and moderate clamping press (a go-bar deck). I don't believe you want to use a great deal of pressure with fish glue since the open time is long.

The scraps were placed outside in a corner for about 1 month. They were exposed to radical shifts in humidity (30% to 85% range). We live right on the intercoastal waterway. It rains often here. The scraps were placed where blowing rain could reach them but they were generally never soaked in water for very long. I tested the joints during a particularly humid day. The result was complete wood failure -- no joint failure at all.

I personally don't feel fish glue is the best glue for bridge joints because they are under the most tension and with high humidity, the joint will likely not be as stable as hot hide glue. However, I use fish glue for many tasks where I need more time than hot hide glue.

For builders who are unable to achieve flawlessly mated parts, I do not recommend the hide glues. You need perfect joints for these glues. I personally would advise that most new or amateur builders stick with Titebond or LMI white glue (both of which are excellent glues) unless you are completely confident that your components achieve a perfect fit. For those who are concerned about the effectiveness of fish glue, I thought I would share my experience.

Thanks for sharing that - it's good to hear as I've become quite fond of fish glue over the last several years.

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Steve Smith
"Music is what feelings sound like"

Who would ever think that a fish glue wouldn't be able to stand up to water?

@Toonces, Thanks for that info, I have used HHG for quite some time and after hearing guys praising Fish Glue here I decided to order some and try it out. The recent post about the perils of fish glue made me just put it on the back shelf so I could do some tests for myself before I used it on anything important. I will still test it for myself but you just moved that bottle to the front of the shelf where I can see it.

Cheers
Bob

Just to clarify, I lodged the pieces vertically on a ladder that rests on the side of our house. Rain doesn't reach unless there is blowing rain -- which does happen here but usually Florida storms pass by quickly. The glue joints looked great -- no opening or separation and as I mentioned, there was complete wood failure. I am pretty certain that the glue joints wouldn't have fared as well if I stressed them right after a storm; hence, my reluctance to recommend fish glue for high humidity situations under a lot of stress. Also, this was just one trial run -- I think you would need a lot more data to come to any definitive solutions. However, most of us base things on anecdotal evidence and so I figured this was relevant. I've been using fish glue for a few years now and haven't had a problem at all.

In fact, I had an instrument that was damaged by FedEx in shipment to New Zealand. By the time I got the guitar back, the instrument was severely swollen from high humidity. The guy didn't realize how humid his environment was. I had to replace the soundboard and let me tell you, as I destroyed the top, the bracing had complete wood failure and the top was a bear to remove from the kerfing. In other words, the fish glue (used for the rims, x-brace, and bridge plate) held up extremely well after being in a very high humidity environment for about 6 months. My personal opinion is that the prep work that goes into a glue joint is by far the most important determinant of whether the joint will function as intended. I am confident in fish glue and its use for many parts of the guitar. Just one more opinion to add to the pot!!!

Hi Bob,
I would do what I did -- prep some glue joints and put them outside somewhere for a month or two and see how they hold up. Again, I would preference HHG whenever possible but I use it for my back bracing and x-brace because it allows me to position the braces exactly where I want without any need to move quickly. Also, it works great on end-grain where you can let the grain soak in glue for about 10 minutes or so before you clamp the joint. I definitely find it useful along with the HHG, epoxy, and CA glues that I use for my builds.

I/ve had similiar problems with 18 mo old fish glue used on uke bridges.In my case it was starving the glue joint .I switched last year to 315 g HHG even though it can be a pita .I joined a 5 pc tamarid uke back yesterday.with 315 it/s tricky and one has to work quickly.

Thanks for sharing. I've recently started using fish glue, mostly for repairs at this point, and I love it. I have used it to reglue a few bridges already and the ability to clean up makes that application very favorable. Seems like a test like that would indicate that it's a good glue for bridges. It dries rock hard and does'nt creep from what I understand.

Hey Toones,

Thanks for sharing this information with us. That said, I'm a little confused. Maybe I'm reading your posts wrong but in the first one you say:

And in a post a little further down you say:


Am I missing something?

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Thanks for that. So far the only thing I do with fish glue is bindings, where the long open time really helps, and fingerboard ends on bolt-on necks, ditto. Neither is really structural, so I'm hoping I won't get into trouble.

I was a bit confused as well. When you say "the results was a complete wood failure" that means to me that the glue joint itself was strong and the wood broke before the glue joint.

That is why I said I was going to reconsider and do some tests myself. Prior to that I put the bottle on the back of my shelf and figured I would find another use for it other than guitars. I will not use a product that I know people are having problems with on a guitar I am building and certainly not on a clients guitar.

Bob

It would appear to me highly probable that "glue" in the second post is simply a typo , and that Toonces meant to say *wood* failure ...

I am a big fan of fish glue and use it now for nearly everything, so I am of course bewildered by the wide variations of stories pro and con it's durability. I have come to believe that over-clamping can be a culprit, due to the long open time. As was the case with some early epoxy joints (slow drying of course), I have managed to so thoroughly starve a few fish glue joints that the parts could literally be pulled apart and the surfaces of the glued joints were nearly clean. I have learned to clamp more lightly and let the glue do it's HHG-like thing. I have one fish-glued guitar body I have been trying to disassemble off and on over the last couple of years (because it has a little twist) and I can't get it apart with water, heat and a palette knife without doing wood damage each time I try.

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Jim Kirby
kirby@udel.edu

Yea. That makes sense.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Sorry for the confusion -- I meant "wood failure". The post has been corrected!!!

Maybe, but I've definitely had better luck/less surprises by not adding that last extra crank/squeeze. (Or maybe I'm just better at gluing, I dunno)

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Jim Kirby
kirby@udel.edu