Hide Glue Part II: Glue making, the basic essentials

about hide glue headerBy Steven Edholm

Making hide glue, is well within the reach of anyone with access to the necessary materials, and is a great addition to your skill set.  In part one I discussed hide glue in general, what it is, and some of it’s strengths and weaknesses.  This article is a combination of personal experience and research into technical aspects of glue making.  Like most people,  I started my glue making career boiling down hide shavings and stray hock skins, without any further preparation.  Glue strong enough for many uses can be made with little care and marginal materials, but over time and with the input of  glue making professionals of the 19th and early 20th century, I found that a little care goes a long way toward making stronger, prettier and better smelling, glue   Here are the most important basic concepts and steps in making very high quality hide glue.

hide glue cube macro

Clarity is a good sign. opaque glue is not necessarily bad glue, but clear glue generally indicates that care was taken in processing.

Common materials for glue making are:  Skin (including fish skins), fish air bladders, sinew scraps, and antler.  (Bone can be used to make a glue, but it is harder to make and inferior to glue from the sources we’ll be talking about.)   All share in common a large amount of a protein known as collagen, which is the basis of both leather and glue.  Hide glue is also sometimes known as collagen glue.

*Skin is easily accessible and easy to work with unless it contains a lot of fat.  It is generally best for the home producer to avoid very fatty skins such as pig, bear and raccoon.  The legs, and other tag ends trimmed from skins before tanning, are a good source of glue stock and were a staple material for traditional hide glue makers.  Fish skins can also be used,  but I don’t have any personal experience using them.

*Fish air bladders are supposed to make excellent glue, but they are not very accessible to most of us.

*Sinew makes excellent glue.  Be sure to collect sinew that is free of meat and fat, scraping it clean as necessary.  The sheaths that surround the tendons in the lower legs of browsers and grazers also make excellent glue.

*Antler, from elk, moose, caribou, deer, etc… contains a good deal of collagen.  The collagen can be difficult to extract, but reducing the size of the antler by grinding or slicing helps. It is important  to note that horn proper, from cows, sheep and goats, is entirely different.  Horn is an outgrowth similar to hair, and does not contain collagen.  Hooves are similar to horn and also do not contain any collagen (see part one for more discussion on that point.)

Previously frozen materials should never be used.

Dried material is preferred over fresh material.

Decayed materials should be avoided.

Ideal steps in Collagen glue making:

*Clean the material:  The very strongest glues are made with un-decayed and thoroughly cleaned materials.  Fats, muscles, dirt and other non-collagen materials are removed as much as possible before the material is boiled.  This can be accomplished by liming, or soaking in wood ashes, followed by thorough, repeated scraping and washing to remove dissolved solids and residual lime.  However, very strong glue can be made by boiling fairly clean materials like sinew and even skin from lean animals without undergoing so thorough a treatment.  At the very least though, skin should be very thoroughly fleshed and washed.

Many materials are best prepared by thorough dehairing, fleshing and scraping, much as for tanning.  Skins are also generally best limed or soaked in woodash to dissolve unwanted fats and proteins.

Skins are generally best soaked in lime or wood ash to dissolve unwanted fats and proteins before thorough de-hairing, fleshing, scraping and repeated rinsing, pretty much as one would in preparation for tanning a skin.

*Dry the material at some point before cooking:  All glue stock should be dried as some point before boiling.  If it has been limed, the stock should be dried after liming and before boiling to change the residual caustic lime (calcium hydroxide) into inert calcium carbonate (limestone).

Materials for hide glue are best dried before cooking.  This glue stock is carefully prepared bull hide.  It was limed and then scraped and washed very thoroughly to remove the residual lime and all unwanted material until very little was left except the collagen fiber network that is the basis of both leather and glue.

Materials for hide glue are best dried before cooking. This glue stock is carefully prepared bull hide. Before drying, it was limed and then scraped and washed very thoroughly to remove the residual lime and all unwanted material until very little was left except the collagen fiber network that is the basis of both leather and glue.

*Simmer the material in clean soft water:  If you have very hard water, buy some distilled water.  Just cover the stock with water.  Avoid scorching the glue stock in the pan.  Traditionally, a layer of straw was often used to line the boiling vessel to keep the glue stock away from the metal, so that it would not stick and burn.

This glue was poured off once and is being re-cooked.  The second batch is harder to extract thoroughly, and in my experience, seems a little less cohesive.

This glue batch was already poured off once and is being re-cooked to extract more of the collagen. In my experience, the second boiling seems a little less cohesive.  BTW, this is in a double boiler, which isolates the glue from flame.  It works well, but is slower than cooking directly in a pot.

*Cool the resulting gelatin solution:  When the glue solution seems thick, cool a small amount in an egg shell.  When ready, it should set upon cooling into a firm, easily handled piece.  Pour the solution into a clean flat pan of some kind, to a thickness of 3/8 inch or less.  When cool, it should be easily handled when picked up with dry hands.  If not firm enough to handle, it will crack apart easily and maybe stick to the hands.  If too wet, evaporate it further in the sun or in a low oven until it will jell more firmly when cooled. If not fairly easy to handle, it will stick to the drying surface.

When gelled by cooling at room termperature, the gelatin should be easily handled.  If it breaks easily, it is either too wet still, or has poor adhesive power due to poor base material, or mishandling at some step.  If it sticks easily to dry hands, it is too warm, or too wet still.

When gelled by cooling at room temperature, the gelatin should be easily handled. If it breaks when handled, it is either too wet still, or has poor adhesive power due to use of a poor base material or mishandling at some step. If it sticks easily to dry hands, it is either too warm, or too wet.  Evaporate until it is  easily handled when gelled.

*Cut and dry the gelatin before use:  When the glue is firm, but still cutable, you can dice it into small cubes before drying further.  Large pieces of glue are difficult to break apart for soaking.If firm enough, the gelatin can be dried on a clean cloth.  The glue must be dried in a cool area with good air circulation.  The un-dried gelatin will turn back into liquid if it gets too warm.  The drier the gelatin becomes, the warmer it can be without melting.  Glue has traditionally been dried on nets.  Glue dried during thunderstorms can be damaged by ozone and may melt.

Large sheets of glue are difficult to break up.  The smaller the pieces, the faster they will soak up when you are preparing the glue for use.

Large sheets of glue are difficult to break up. The smaller the pieces, the faster they will soak up when you are preparing the glue for use.

Glue can be dried on a clean cloth if it is firm enough not to stick.  This glue is almost finished drying.  A fan is very helpful when drying glue.  Just keep it out of sun and heat or it will melt and you'll be all &%^%$$#!!!

Glue can be dried on a clean cloth if it is firm enough not to stick. This glue is almost finished drying. A fan is very helpful when drying glue. Just keep it out of sun and heat or it will melt and you’ll be all like, &%^%$$ ##@$!!!

Note the deeply indented centers and sharp edges of these glue pieces.  That is a sign of quality.  What it indicates is that the adhesive power and solidity of the gel was so great that it could be firm while still retaining a relatively high water content.  A weaker gel would have fallen to pieces with so much water.

Note the deeply indented centers and sharp edges of these glue pieces, a sign of good quality. What it indicates is that the adhesive power and solidity of the gel was so great that it could be firm enough to handle while still retaining a lot of water.  A weaker gel would have fallen to pieces with so much water.

Now you have glue.  Skipping some of these steps such as drying the material before boiling, cleaning the glue stock thoroughly, or drying the gelatin, will result in a usable and sometimes even very strong glue.  However, all of these steps combined and executed properly will assure that you end up with very a very high quality product.  Glue is not the best place for sloppiness and procrastination.  Believe me.  Here at Paleotechnics, we’ve already made all these mistakes for you!

To drive home some of these points, here is what not to do!

*Don’t freeze the glue materials before boiling.

*Don’t use decayed materials.

*Don’t use greasy, fleshy or dirty materials.

*Don’t burn the glue material in the pot.

*Don’t let the boiled solution sit around and decay at all before drying it out.

*Don’t make, use or dry glue during lightning/thunder storms (ozone supposedly affects glue quality causing it to lose it’s jelling power.)

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8 Comments

  1. This series contains great information as usual. Keep up the amazing work!

    I usually use hide glue in an outdoor campfire environment while teaching. To facilitate the quick re-melting the glue with a sometimes finicky heat source, I have processed the glue as follows. When making a batch of hide glue I pour a thin layer onto a metal pan to cool. Then by gently twisting the pan the glue cracks off and I have a bunch of really fine flakes that will readily turn back into a liquid due to their low individual mass, usually heated up in a large clam shell. I usually start with a small amount and once it is liquid I can slowly add more flakes as they will melt quickly due to the liquid contact area. I usually use the liquid hide glue as a binder for pigments on hide and wood.

    I learned most of what I know from your classes!

    Reply
    • Hi Chuck! That’s a cool idea. I’ve done that inadvertently while cooling hide glue in pans and it does dissolve really fast. commercially, they grind it to make it fast to reconstitute, but I’m not sure that’s within my means, though I haven’t given it a good go yet. It does take a really long time to swell all the way if it’s in larger pieces like I usually cut them. I’ll try making a few like that next time I boil a batch. The next time I get a cattle hide, I think I’m going to make a large vat of hide glue. I’m encouraged by the quality of my last batch. Thanks for the praise. You keep up the good work too. I know you’ve reached a lot of people over the years.

      Reply
  2. R.K

     /  December 15, 2016

    Hi, may I know the reason why previously frozen materials should never be used? Sometimes I make glue from previously frozen sinew and found nothing negative from the yield.. thanks in advance

    Reply
    • Hi. That is something I picked up from an old glue making manual, but I also experienced problems using previously frozen material. Interesting that you have used it without apparent problems.

      Reply
      • R.K

         /  December 15, 2016

        Well, I didn’t do any comparison test though.. the glue is exceptional, but I’ll check on my next batch..

        By the way, I think this blog and your youtube series is very good and thorough in explaining the hide glue making..

      • R.K

         /  December 15, 2016

        Well, I didn’t do any comparison test though.. the glue is exceptional, but I’ll check on my next batch..

        By the way, I think your blog and youtube series is very good and thorough in explaining the hide glue making..

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