Fish Glue

I hate watching television even though I have two TV’s in my house but thankfully never used, I can’t stand listening to the news because there’s never anything positive to hear but they’re usual over dramatization and fear mongering tactics.  I hate politicians, because they never keep their election promises, constantly lie, they live in the back pockets of corporations, they pretend as if they know what they’re doing and they just can’t seem get along without resorting to some kind of war.  Oh, and they’re radicals because they’re ignorant.  A professor at Griffith University at the school of law once said “Ignorance breeds radicalism.”

So, I turn to books and articles written by prominent highly educated and respected people on various subjects pertaining to my interests.  I was recently doing some research on hide glue and it’s uses and made some amazingly new discoveries which could have helped me during my build of the small router plane.  Prior to the build, I was blinded to this information but a few days after the second build I make this discovery.

Did you know that metal expands and contracts with humidity and temperature fluctuations in opposite direction to the wood?  In fact, so does water.

heat-20-728

Did you also know that epoxy is brittle and the metal glued to wood would eventually break off?  Just when this will occur is anyone’s guess, but since I’m all about quality workmanship and having my builds outlive a generation or two at the very least, why take the risk.  I’m sure you feel the same.

Prior to knowing these facts about metal’s movement during these environmental fluctuations I was stumped on understanding why epoxies brittleness would eventually cause bond failure. Well now it all makes sense, this important bit of information I wasn’t made privy to all makes good sense, “movement”.

As woodworkers, we expect for wood to move and we make accommodations for that movement but how many of us knew that metal moves as well and in the opposite direction to wood. So, scientists came up with a solution of gluing metal to wood and that’s Loctite 330 and there are other numbered Loctite’s that will also do the same trick but, wait a minute. Isn’t antique furniture covered in brass ornaments, doesn’t some antique braces have brass plates fixed to them, ok fair enough they’re reinforced with screws but what about antique clocks and their brass fittings.


So, if these metal fixtures were glued to the wood hundred of years ago and are still affixed firmly in place today, what did they use? I’m sure Loctite didn’t exist in that era, well the answer is animal glue and fish glue to be precise.  According to Patrick Edwards fish glue was used in marquetry to glue ivory, bone, horn shell and metal (brass). Which makes perfectly good sense because all animal glues allow a certain amount of movement of these elements.

There are a variety of traditional animal glue applications that continue to be used by modern craftsmen. Rabbit skin glue is necessary for laying gold leaf properly.  Instrument makers and restorers have a wide variety of applications that depend on animal glues. For example, the fact that these glues can be coloured and mixed with many components allows the addition of plaster of Paris to glue for laying ivory keys. Marquetry workers add different colours to the glue to restore Boulle tortoise shell and make mastic. Fish glue has properties which make it perfect for exotic materials, such as tortoise shell, horn, leather, shark skin, cloth and metals. Fish glue is a liquid glue with strong cold tack grip, and its used to glue brass, pewter and copper in Boulle marquetry is further strengthened when the metal is first rubbed with a fresh clove of garlic. Animal bone and hide glues are used individually and mixed together for all types of woodworking. Diluted glues are used for veneer sizing and flattening, as well as for sizing end grain and porous woods before sanding.
Had I known these facts before I would have used fish glue and come to think of it I actually have a bottle I bought a number of years ago, I doubt very much if it’s of any use anymore in fact I just opened it for the first time and took a whiff and it stinks, but I’ll glue some small pieces with it just for fun to see if it will work being so old as it is. Having said that, Fish glue will still be good for a number of years even though it is a protein glue and fish glue is smelly by nature anyway, so the stench of mine is probably normal.
You have to admit the benefits of using animal glues far outweigh the benefits over synthetic glues, yes, it’s true there’s no ease of use.  It’s time consuming to prepare and you have to keep an eye on it constantly so it doesn’t over cook, if you’re working in a fully-fledged business production run workshop your glue must be hot and ready for use throughout the day. But, that’s life and that’s how it’s always been for the last 8000 years with this glue.
Here’s one more tip you also probably didn’t know. Cold water is added to dry glue and hot water equalling the temperature of the hot glue is added to thin it. Cold for cold and hot for hot and yet I see on YouTube cold water added to hot hide glue. If you’re going to use cold water then allow the glue to heat up to 140° F (60°C) before you use it, don’t do what I’ve seen people do and use it straight away and it’s not just on YouTube but in a particular book as well.  If I mention which book then the author/seller will get all snotty with me, funny though I must be the only one that will cop it in the chin when I get it wrong, I learn from it and move on but when it comes to them they hold a grudge and take it with them to their graves.  This is called online woodworking politics and there is a lot of that.

Take care

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6 thoughts on “Fish Glue

  1. A quick update on the fish glue test, it’s been drying for about 10hours now and still feels a little tacky but the bond is very strong. I can’t pull the two pieces apart apart and the material I glued is light coloured and the glue line is very faint. I will see if it cures in 12 hours time if not then this bottle is out of it’s used by date, in the meantime I’ll do some further research on this glue.

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  2. 24 hours has passed and this glue has cured there’s no tackiness and the join is solid pretty amazing considering the glue is about 5 years old. I love the long open time and its clear which is great for light coloured timber. They say it’s not as strong as hide glue but if it can bond metal to wood it’s definitely strong enough. Maybe I’ve just resolved another myth created by makers, marketers and other supporters of synthetic glues.

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    1. From what I have read so far you use it in its cold state. The bottle I bought from lee valley the glue is in a liquid state and runs off easily from the brush much like hide glue and syrup description. I will do some further research on it.

      Liked by 1 person

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