My early mentor, Buckskin Slim, used Elmer's for backing most of his bows, but had also used boiled down salmon skin glue. I'd eaten hundreds of boiled trout on survival trips and knew how sticky the skins became, but at the time it made more dietary sense to eat the skins rather than experiment with glue making (Perhaps Tim Baker will relate his experiments with fish skin glue).
The category "hide glue" sounded simplest and stuck somewhat dormantly in my mind. I was not then aware that commercial "rabbit skin" glue existed. Finally, about 15 years ago, the need for glue and the impetus for addressing that particular experiment coincided; I had finished a nice Serviceberry bow, wanted to sinew-back it and was determined not to use Elmer's!
The Original Experiment...
Since I'd been brain-tanning buckskin for several years, I always kept a stash of hides, and found some scrap pieces of deer and elk rawhide laying around. As whole hides, these had been fleshed while fresh, laced into frames to dry and the hair scraped off. The vast expanses had been used for quivers, other containers, knife sheaths, etc. With tin-snips I cut up a handful of dry scraps into 1-2" square pieces and plopped them into a #10 can of water boiling on the stove. An hour or so later, besides the interesting aroma that pervaded the house, I noticed the skin scraps were swelling and becoming somewhat gelatinous to the touch. As the water boiled away, I added enough more so as to not burn the skin. A couple times I'd quickly dip a finger into the soup, but noticed no discernible stickiness. A couple hours later it had again boiled down, seemed a little thicker than plain water and was becoming a translucent brownish color. I again dipped in a forefinger, smeared it on thumb to an evenly thin layer, blew on it a couple times to evaporate a bit more moisture, then tightly squeezed thumb and index finger together for about 30 seconds. The result surprised me, amazed me . . . and freaked me out -1 honestly could not pull finger and thumb apart. Eureka, I've finally discovered glue! However, I still had this problem. Fortunately, I more rationally remembered the glue is water soluble, and a rinse in warm water returned my use of thumb and finger as separate appendages.
Since that enlightening day I've made and used gallons of hide glue and can better describe my own "how-to" process in a sequential series of steps, tips, do's and don'ts, though I'm sure there is more to learn.
Note the curls of skin - seperate from hair for glue making.
The Hides ...
I suppose almost any skin will produce some glue, but larger, thicker hides as deer or elk seem more energy-efficient. If a hide has been salted for storage, I think it advisable to thoroughly soak and repeatedly rinse it in water to dissolve away as much salt as possible. You can use any pieces of skin, green or dried, but they should be fleshed clean of any meat or fat, and I prefer to have scraped off the hair prior to boiling them up. Initially, the hair is not detrimental, it just adds extraneous bulk, but you don't want hair in your final glue. Once I've boiled the mass to the point where the skin is well-cooked (swollen and gelatinous) and the glue has gone into the water, I pour all the liquid through a piece of window screen to strain out all skin pieces and hair. Cheesecloth or similar fabric is a bit slower but even more thorough in straining out hair.
Forthe last several years I've refined my glue process even more by using hide shavings, a natural by-product of making buckskin. In the dry-scrape buckskin tanning process I begin with a clean fleshed deerhide. It can be freshly peeled from the carcass, or most often is one I've previously dried or salted for storage, then soaked in plain water 24 hours or so until it's thoroughly wet and pliable. Either way, I cut inch-long slits parallel to the edge of the hide, 1/2" in from edge, every 3/4" around the hide perimeter. Then I lace or tie it into a rectangular pole or two-by-four frame fairly tightly and evenly stretched. As it dries over a day or two it shrinks and becomes even tighter, so some practice is required in not stretching so tightly at first that, as it dries, it rips out some of the ties. When dry, I begin scraping off the hair and epidermal layer of skin which lies beneath it. The scraper is a steel blade roughly 4" long, 1 1/2" wide, 1/8" thick, with a rounded cutting edge sharpened on a single bevel. This blade is lashed or screwed onto an elbow-shaped handle of wood, antler or flat angle-iron (see illustration).
If my goal is just getting the hide adequately scraped for the next step in making buckskin, I quickly shear off both hair and grain (epidermis) together with only one or two brisk strokes at any specific area as I work down and across the whole hide. When I want shavings for glue, however, I scrape more lightly to remove only the hair. When done, I clear it away from the base of the frame. Then I go back over the whole hide again shearing off the now mostly hairless epidermis. With long smooth strokes of the scraper blade, this comes off in thin curled shavings much like a plane removes shavings of wood. I then collect all these shavings which, since dry, will not spoil and store them until I need a batch of glue. Some hair remains in the root follicles of the shavings and other fluffs of hair unavoidable get mixed in, but are immaterial at this stage.
Making Glue ...
My standard, all-purpose, old reliable camping pots, stew pots, tea pots and glue pots are #10 cans (roughly 2-3 lb. coffee can size). I punch opposite holes just below the rims and attach wire bails for easy manipulation. For glue, I jam a couple big compressed handfuls of hide shavings into the pot, say, a well-packed 2/3 full, and fill with hot or cold water to 3/4 full. Since the shavings are so thin, they immediately soak-up a lot of water. I bring this to a rolling boil, pot uncovered to reduce boil-over potential. And maintain the boil for an hour or so, adding more water as needed. At this stage don't worry about too much water-more is better than less to prevent burning the skin. I stir this glop frequently. After an hourthe shavings should be swollen and gelatinous. I pour off all the liquid through a screen or strainer into a second pot, refill and reboil the first for another half hour, then strain that into the second pot. This time I also hand-squeeze the skin glop to get most liquid out and discard the skin as compost. By this time most of the glue from the skin should be in the water.
Besides the fact the skin shavings soak and boil up quickly, I believe this mostly epidermal layer contains proportionately more glue than the rest of the hide, though this theory remains objectively untested. In my experience with shavings, one pot's worth makes enough glue to easily back one bow, with considerable glue left over. Again, for an expected ration of raw skin to finished glue, more experimentation could be done; I'm simply not into the real statistical end of it!
Whetheryou've boiled upfresh skin, dry skin, hairy skin, skin shavings, etc. and strained the liquid, you now have quite a pot of milky to tan-colored soup, free of most hair and actual pieces of skin, but still way too thin as is for glue. As you further boil this down and as water evaporates to a quarter pot or less, the "incipient glue" should become more viscous and somewhat darker. I use different viscosities of glue for different jobs, but generally seek a consistency slightly thinner than the commercial LaPage's mucilage in the pear-shaped bottle with the pink rubber spreader on top (the stuff you probably used in grade school, if you're old enough, anyway!). To check your glue for adequate adhesive qualities, just try the previously described finger/thumb test. If not sticky enough, boil it down further Make sure you cool it down enough before use though, or it'll cook and rubberize your sinew! And for immediate use, that should do it, but, there is definitely more to know about your newly-made glue.
The Nature and Care of Hide Glue
I must confess that I consider hide glue, like sinew, to be a nearly magical medium, sort of like a living organism with a mind of its own! By most of our contemporary concepts of logic and application, it should not be able to accomplish what we know it can (by the laws of physics, a bumblebee should not be able to fly either), but we must produce, manipulate and treat it within its own necessary parameters for it to serve us well. Ignore or forget it too long in the wrong condition (that can mean you, or the glue!) and it'll turn fickle quite rapidly on you, moldin
g or rotting with the stench of death.
Let's say you've made a batch of glue but aren't going to use it right away or have glue left over after a project and want to store it. Since I feel I've already done almost everything' wrong with hide glue at least once, I feel qualified to offer some do's and don'ts. The only way I know to store hide glue indefinitely is to completely dry it down, and this is an active process using a direct heat source, without heat, a pot of glue, even perhaps only 1 -2" deep, if left to just sit will soon glaze over and begin to harden on top, but remain liquid beneath that and soon spoil. The glue does not have to be boiling to be drying, though with low heat the surface glaze should be broken through periodically to allow quicker evaporation from beneath. Refrigeration or freezing may delay spoilage or mold for a few days, but I've had small cans of glue go bad within a week, whether frozen or just cold. The other two "safe" but temporary conditions are actively reconstituting dry pieces or crystals with water and heat to the consistency for use, or actively drying it back out after use.
My wood heater is perfect for either process as the heat source is continuous and the temperature adjustable by the amount and kind of wood and by moving a glue pot to different areas of the stove surface. I also keep a grate set on a couple bricks a few inches above the stove top and have drying screens above and behind the stove. Thus, when I add water the glue is reconstituting and after use it is automatically drying back out. With a large pot of glue intended for storage, I usually just dry it down to a solid layer and leave it in the can. When thoroughly dry, this hard, flat translucent disc of brownish glue has shrunk away from the sides and bottom of the pot and can be removed for travel or storage elsewhere if desired. Dry chunks can be pounded or ground into finer pieces or crystals like the commercial hide glue. The crystals of course reconstitute faster than chunks. In actively drying down a pot of glue, it naturally becomes thicker and thicker until it congeals into the "Jello" phase, thence through the rubber and leather phases on its way to the inert rock phase. Once it is no longer liquid, care must be taken not to burn it. When congealed and dry enough to be rubbery and not sticky to the touch, the entire glob can usually be eased from the can with a butter knife and dried on a screen as is or sliced like cheese into thinner slabs for quicker drying. If you don't have time to carefully boil a whole batch all the way down, you can rapidly boil it until quite viscous but still liquid, then pour a thin layer into a flat pyrex or enamel casserole dish, onto a non-greasy cookie sheet or even foil and sun dry or place in an oven set on warm. A thin layer will usually dry quickly with little chance of spoilage. Unless preparing to back a bow, I normally need only small amounts of glue, but quite regularly, for hafting, fletching, etc., so I always keep a tuna can with some dried down glue near the wood heater. This requires only a dash of water and a couple minutes of heat to be usable, and quickly dries back out.
The Open-ended Finls...
There is a definite satisfaction in doing more with less and being directly familiar with and responsible for all phases and materials in any aboriginal project one undertakes. The ability to make your own glue is one such endeavor, one useful product of a process. As with any process repeated enough, you'll eventually learn what you must do to be successful, what you must not do and, yes, what you can get away with! Well-made hide glue, your very own hide glue will forever bond you to its wondrous merits.
Mummy Varnish, Spruce Gum and Other Sticky Stuff
By Scott K. Silsby
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As interpreted from archeological findings, the history and prehistory of adhesives stretches back to the earliest signs of hafting. Some of the earliest are the late Mousterian tool kits associated with Neanderthal culture. They certainly had a wide range of adhesives from which to choose, as nature's warehouse offered an inexhaustible range of plant resins, rosin, pitch, tar, sap, gum, oil, sugar, starch, latex, bitumen and such not including the various animal glues and products like shellac, bees wax and propolis. From a replication standpoint, knowing the time, place and culture of an artifact would help narrow down what choices were available for adhesives.
Some formulas for hide and fish glues read like an alchemist's worst nightmare. In Turkish Archery and the Composite Bow (Klopsteg, 1934), he summarizes Turkish bow glues and describes the several day process of simmering sinew in rainwater, fat skimming and rendering it into a form "like leeches". Fish glue was obtained from the skin of the roof of the mouth of the Danube Sturgeon (in these days: Gadus morrhica). It was fried and shipped to market, resoaked, pounded with a wooden cudgel on a marble slab. The cudgel was frequently moistened with the tongue since water was said to spoil the glue at that stage. Some of these "hot" hide glues are rated at 20,000 pounds per square inch. In some cases the two glues were combined. A good bit of this early primitive technology was highly sophisticated and efficient. Keep in mind primitive means first, not worst. The early archery records of these ancient folk still stand as testimony to this.
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As interpreted from archaeological findings, the history and prehistory of adhesives stretches back to the earliest signs of hafting. Some of the earliest are the late Mousterian tool kits associated with Neanderthal culture.
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One basic adhesive that was used extensively throughout most of the world for a wide range of purposes and is well documented are the various conifer resin products referred to as Naval Stores in the commercial track. This industry antedates the Christian era in the Mediterranean region. In his article Naval Stores: The Industry (Ward, 1949), Jay Ward tells of early accounts of the process used where natives gathered resins or gums of trees and cooked them in open pots until a thick pitch was left in the bottom. They stretched fleecy sheep skins over the tops of the pots to catch the oily vapors that arose from the boiling gum then wringing out the wet fleece to recover the oils. He goes on to tell that one of the uses was varnish for mummies. He further describes a vast commercial operation in the production of tar, pitch, rosin and turpentine that supplied products to all the wooden sailing vessels of all the European nations. The industry through time shifted from Scandinavia and the Baltic countries to New England then through New Jersey into Virginia, winding up in the Carolinas where, at its peak, 1,998,400 drums of gum rosin at 520 pounds each were produced. That's a lot of sticky stuff.
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Keep in mind that "primitive" means first.... not worst.
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The French, Spanish and Native Americans were busy making war on the conifers, as well, for their own needs. The unsurpassed birch bark canoes of the past incorporated carefully prepared resins for waterproofing and strengthening joints.
For many of us, our interest in all this is more towards the practical aspect of finding a workable natural material suitable for hafting stone to wood, bone and such. While many things work, spruce gum has become my resin of choice. My experience with the stuff occurred when I tried to arm my giant ragweed stem arrows with slate "error-heads" (concrete slab ground, notches punched with a nail). Although that was nearly forty years ago, my failure with hot hide glues for that aspect of gluing and success with raw pine pitch and kite string (cotton) is well remembered today: Good glue—wrong use! As hide glue dries, it continues to shrink until an equilibrium is reached with the humidity. In dry regions it becomes quite brittle. In humid regions, it stays flaccid. In hafting stone to wood, it keeps shrinking. As it pulls the wood haft area tight, it breaks loose from the stone and becomes nothing more that a filler in the haft area. When damp, it's like tight rubber bands.
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From a replication standpoint, knowing the time, place, and culture of an artifact would help narrow down what choices were available.
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A system I worked out through trial and error over the years since that first discovery has given me good service so I pass it along as one way to get it done, although not the only way.
&
nbsp; Don't be too picky about whether it's spruce, pine, fir or such. Spruce seems best but a mixture of conifer resins is fine or all pine does well also. If damaged resin-bleeding trees can be had, use them. Second choice is collecting rosin balls and drippings that are dry to semi-dry. Scrape them into a sealable jar, add turpentine (half and half) and periodically shake the mix over a day or two until it appears dissolved. Strain out bark, bugs and needles then either set in the sun with the lid off to evaporate excess turpentine or rig up a double boiler outside to speed it up. Turpentine vapors are quite flammable and give off thick black soot and heavy turpentine odors if they catch fire. Never cook it in a sealed container and smother flash pot fires with an old loose fitting lid to prevent explosions.
I dislike the process of slashing trees to bleed them so will skip over that technique. Any National Forest with camping areas will be rich in vandalized trees as well as the edges of construction sites.
Primitive Technology Page 28