Is Fish Glue suitable for gluing Braces?

[CMStewart]

I've heard humidity can cause the glue to fail. I really don't feel up to using traditional Hide Glue (being a new builder/hobbyist). So I've been thinking about using Fish Glue. But I can't seem to find solid advice on if it's suitable for braces.

My other thought is using Old Brown Glue, which is hide glue but can be heated and used from the bottle, and re-used later. So not as difficult as traditional HHG. It also has a longer set time, which will be helpful for me. I'm curious what other builders think of these options. I know plenty use Titebond also. But I'm just curious about other's experience with these glues in particular.

- Colby

[Tim McKnight]

Old Brown won’t dry as hard as HHG.

Fish glue will fail in high humidity. In dry conditions it’s fine.

Learn to use HHG. Practice your dry clamping multiple times and as long as you can clamp your (accurately fitted) joint in 20 seconds or less it’s your friend. If you can’t clamp it that quickly and the glue gels the joint will fail. HHG will not fill gaps in poorly fitted joints.

[Andy Bounsall]

Originally Posted by Tim McKnight

…Fish glue will fail in high humidity. In dry conditions it’s fine.

Tim, do you have firsthand experience with fish glue joints failing due to high humidity? If so, how humid and for how long? I’m curious because I’ve heard this statement in the past but have also heard of fish glue being used successfully for guitar joinery for years. Fish glue does have certain properties, such as long open time, that’d make it desirable and some, such as long clamping time, that are less desirable. We tend to try and keep our guitars in relatively stable and moderate temperature and RH levels in North America so I wonder if the warning of fish glue potentially failing in high humidity is more appropriate for instruments that will spend their lives in more tropical climes?

[CMStewart]

Originally Posted by Tim McKnight

Old Brown won’t dry as hard as HHG.

Fish glue will fail in high humidity. In dry conditions it’s fine.

Learn to use HHG. Practice your dry clamping multiple times and as long as you can clamp your (accurately fitted) joint in 20 seconds or less it’s your friend. If you can’t clamp it that quickly and the glue gels the joint will fail. HHG will not fill gaps in poorly fitted joints.

I too have heard about fish glue being susceptible to humidity, but have also heard it being used successfully (it seems a lot use it for joining the plates to the sides, which makes sense given its longer set time). I've seen some claim that they used it for the entire build, but those are scattered and have little detail on if there has ever been an issue later on.

As regards Old Brown Glue, I have not seen any actual data to substantiate that it is not as strong as HHG. It seems that if you use it as intended (heat it up, clamp it, and give it around 24 hours to cure), that it shouldn't have any less strength than 192g HHG. I've even seen one test showing it was stronger than HHG, but none showing it as inferior. So I'm really curious if this is just theory (because it contains urea), or if it's been demonstrated through some kind of testing.

[Bruce Sexauer]

Aside from requiring to be mixed with water and heated, and used with some efficiency time-wise, there is not much I’d call difficult about using HHG. Once one knows how to monitor it’s viscosity, it’s a simple matter to add a bit water now and again as it dries out. People who haven’t used it seem to call it difficult, people who do use it never seem to say that.

[Tim McKnight]

Originally Posted by Supercurio

I too have heard about fish glue being susceptible to humidity, but have also heard it being used successfully (it seems a lot use it for joining the plates to the sides, which makes sense given its longer set time). I've seen some claim that they used it for the entire build, but those are scattered and have little detail on if there has ever been an issue later on.

As regards Old Brown Glue, I have not seen any actual data to substantiate that it is not as strong as HHG. It seems that if you use it as intended (heat it up, clamp it, and give it around 24 hours to cure), that it shouldn't have any less strength than 192g HHG. I've even seen one test showing it was stronger than HHG, but none showing it as inferior. So I'm really curious if this is just theory (because it contains urea), or if it's been demonstrated through some kind of testing.

A good friend and peer (who shall remain nameless) shipped two guitars to Singapore of which the top braces were joined with FG. Two weeks later both tops imploded due to multiple glue joint failures. He had to eat the shipping $$$ cost $$$ both ways, then replace both tops $$$ and never used FG again. We ship a fair amount of guitars to high humidity countries and his experience was reason enough for me to never use FG.

I never said Old Brown Glue wasn’t as strong. I said it doesn’t dry as hard as HHG. It’s simple to measure the hardness with a durometer gage.

[CMStewart]

Originally Posted by Tim McKnight

A good friend and peer (who shall remain nameless) shipped two guitars to Singapore of which the top braces were joined with FG. Two weeks later both tops imploded due to multiple glue joint failures. He had to eat the shipping $$$ cost $$$ both ways, then replace both tops $$$ and never used FG again. We ship a fair amount of guitars to high humidity countries and his experience was reason enough for me to never use FG.

I never said Old Brown Glue wasn’t as strong. I said it doesn’t dry as hard as HHG. It’s simple to measure the hardness with a durometer gage.

Tim - my apologies for misunderstanding (hardness vs strength).

That was my fear with Fish Glue (humidity causing it to fail). I guess I hadn't heard of specific examples, but those help. Thank you for sharing them.

In terms of hardness, do you know where OBG would stand when compared to PVA glue? (i.e. Original Titebond).

Bruce -- there are a few issues for me jumping right into HHG. The main one is probably the small open time. I am a brand new builder, and I work full time with another job and probably won't have a ton of time to practice (at least for the time being), and having something that will still work, have a longer open time for me, and still be reversible in the case of mistakes, would be best for me for right now. I have a lot I'm learning and I just feel I will jump into HHG later once I have some of the other techniques down in the process of building. These may sound like excuses, but learning all the things I am is really enough without the challenge of using HHG at this point.

Old Brown Glue, assuming it will still work (meaning it won't fail) right now seems most appealing as I'm starting out. It is reversible, has a longer open time than HHG, and -- though not as hard as Tim has said -- still seems better than PVA glue. Right now, I'm mainly concerned with whether these glues are going to fail in these applications.

[Bruce Sexauer]

The actual hardness of glue may matter because the energy in the strings travels from one piece of wood to another through the glue joints, and softer glues are almost certainly “higher damping”, by which I mean they are getting in the way of the energy flow. I clarify because it has been pointed out to me in the past that I am possibly misusing the term “damping”.

A relatively soft finish such as the oil varnish I use also has a higher damping than a harder finish, but it is damping the overall nature of the tone rather than the functional integrity of the mechanics, and the result is actually pleasant rather than an impairment.

IMO, of course.

[CMStewart]

Originally Posted by Bruce Sexauer

The actual hardness of glue may matter because the energy in the strings travels from one piece of wood to another through the glue joints, and softer glues are almost certainly “higher damping”, by which I mean they are getting in the way of the energy flow. I clarify because it has been pointed out to me in the past that I am possibly misusing the term “damping”.

A relatively soft finish such as the oil varnish I use also has a higher damping than a harder finish, but it is damping the overall nature of the tone rather than the functional integrity of the mechanics, and the result is actually pleasant rather than an impairment.

IMO, of course.

I'm curious if there's a test showing the relative hardness of HHG, Old Brown Glue, and Titebond Original (used by many builders today). I'm curious if the urea in Old Brown Glue makes it inferior to PVA in terms of hardness, or if it is still superior to PVA, even if it doesn't meet the level of HHG.

[Tim McKnight]

I've written a couple of articles about glue and vibration energy transference but they don't include OBG or FG. Sorry but they were not available at the time I performed these tests many moons ago but the data is still relevant. LMII's white glue is no longer available here in the US either.

https://mcknightguitars.com/more-info/special-projects/

[Andy Bounsall]

Originally Posted by Tim McKnight

I've written a couple of articles about glue and vibration energy transference but they don't include OBG or FG. Sorry but they were not available at the time I performed these tests many moons ago but the data is still relevant. LMII's white glue is no longer available here in the US either.

https://mcknightguitars.com/more-info/special-projects/

Interesting stuff Tim. Thanks for sharing it.

[sinistral]

Originally Posted by Andy Bounsall

Interesting stuff Tim. Thanks for sharing it.

Seconded! I ended up reading all of the articles/experiments—very interesting! It’s no wonder your guitars sound so good!

[Carey]

I am not a professional maker, but have done fairly rigorous tests of Norland Fish Glue and Old Brown Glue. If I were sending instruments to very humid
places I would not use fish glue, but it's my preference between those two for its ease of use, hardness of drying, and general tenaciousness. I think fish glue is definitely more hygroscopic than hot hide glue and doesn't dry *quite* as hard, but to me it's clearly preferable to Old Brown Glue for use on musical instruments.

Adding: easy reversability and cleanup are not fish glue's strengths, and it needs plenty of clamping time.

[Jlhunt]

Originally Posted by Tim McKnight

I've written a couple of articles about glue and vibration energy transference but they don't include OBG or FG. Sorry but they were not available at the time I performed these tests many moons ago but the data is still relevant. LMII's white glue is no longer available here in the US either.

https://mcknightguitars.com/more-info/special-projects/

Tim, I read your article on glues several years ago when I first started building guitars. I found it very interesting. I had been building Arts and Crafts style furniture for many years and took a class on glues from the individual who developed the Old Brown Glue and used it successfully on furniture.

After reading your article I used HHG for some parts of my builds and LMI glue for other parts. I have been using LMI glue now for years with good results. After your comment that the LMI white glue you tested was no longer available I panicked.

I went on the LMI site and realized I have been using LMI's yellow luthiers glue. Do you or anyone else have any comments or advice on the use of this glue in building.

Thanks, Jim

[Tim McKnight]

Originally Posted by Jlhunt

Tim, I read your article on glues several years ago when I first started building guitars. I found it very interesting. I had been building Arts and Crafts style furniture for many years and took a class on glues from the individual who developed the Old Brown Glue and used it successfully on furniture.

After reading your article I used HHG for some parts of my builds and LMI glue for other parts. I have been using LMI glue now for years with good results. After your comment that the LMI white glue you tested was no longer available I panicked.

I went on the LMI site and realized I have been using LMI's yellow luthiers glue. Do you or anyone else have any comments or advice on the use of this glue in building.

Thanks, Jim

Hi Jim,
I don't know for a fact but my hunch is that their yellow glue is VERY similar to Titebond yellow with an added florescent dye added. Its obviously working or Chris would not be selling it so I would not panic.

You can put a few drops, enough to cover the bottom of a paper Dixie cup and do the same with HHG then allow both to dry for a few days then tear the cups apart to get down to the glues. Afterwards see if you can imprint the dried glues with your thumb nail. That will give you some tactile comparison of their respective hardnesses.