Posts filed under adhesives

Opinel No 8 Knife Modifications and Cheese Glue Experiment

The videos below are about modifying a popular knife.  This basic French Opinel No. 8 model is a lightweight, easy to sharpen pocket knife that whatever combination of reasons has stood the test of time.  I like a few things about it, and dislike a few, so I picked one up to play with and modify as necessary.  What I do like is the thin carbon steel blade, the light weight and the low cost.  It is similar to a sheath knife in size and function, but the folding design and the light weight make it an entirely different animal than most pocket knives.  It doesn't weigh down your pants or draw any attention in the pocket.  I dislike the small round handle and the shape of the tip of the knife.  I'm also not crazy about the sharp radius on the belly near the tip, but haven't yet modified that. As far as build goes, I'd say it's well put together for what it is, though there are obvious limitations and potential pitfalls, mostly in the joint "hinge" area.  The joint can only be so strong and the wood is obviously prone to swelling and shrinking.  That said, robustness is far from everything.

Many modern knives are overbuilt to my way of thinking.  I think the phenomenon is due to overthinking extreme scenarios where strength is paramount because survival of the knife is equated with survival of the person.  If functionality for everyday common tasks, or even important infrequent tasks is lost in favor of robustness, then the design has in turn lost me.  While this is far from a robust knife, and certainly may not be hurt by a dose of robustness, it does seem like it has potentially good functionality for a lot of everyday stuff and things that are important to me.  If it is damaged or worn out, it is inexpensive to replace and ditto if it is lost.  As a beginner knife, there are certain advantages to a cheap knife, but also to a not-too-robust knife.  With this knife a new user that puts it through the learning experience is not likely to be left with a false sense of security that might be imparted by an overbuilt knife.  The thin blade, weak attachment point and delicate tip are not going to withstand much abuse.  Honestly, bending and breaking tips, mangling edges, loosening joints or even outright breakage are almost an essential part of the learning curve that will serve well down the road.  Where else do we learn the limits of our knives, but by crossing them?

I've not used it enough to know if there are other things that I will really dislike about it, but will probably use it a lot and none too gently, although I'm not likely to flagrantly abuse it.  I've used enough knives and have enough opinions that I would already like to see a model that is optimized for more all around use, though modifying this one is not so difficult.  There is also a model with an unfinished handle that can be carved to suit the user and it's the same price roughly.  I haven't seen it in person, but it might solve the handle issue and even an inexperienced filer can probably take the tip down to make it more functional in 15 minutes or less with a sharp file.

The shape at the tip of the knife just has to go.  This is the most important, non-negotiable modification, requiring just a few minutes of filing.  This mod puts the tip more in line with the center-line of the knife and makes almost every task I would do with the tip easier from cleaning fingernails, to detail carving, to cutting leather and paper on a flat surface.  I can't really think of anyplace that the original tip design is going to be really advantageous for me, and it is nearly always disadvantageous rather than neutral.

The handle size and shape is not very functional.  It is round, so it turns in the hand too easily.  It is also small and doesn't fill the hand up, which can cause cramping and require excessive grip to keep it stable, especially since it is round and prone to turning.  And finally, it is hard to tell how the knife is oriented in the hand without looking at it.  The shape of the base gives some idea of the plane the blade is oriented in, but it's not like the simple automatic feel of an oval handle which drops the blade right into line where it should be.  I used some wood shavings with casein glue as an experiment toward a sort of natural glue laminate to build the back of the handle up.  Cheese glue is more or less waterproof or water resistant, otherwise I would have used hide glue.  I'm not sure I got the mix right or if this will really be water-proof/resistant.  I really need to do some formal testing and experimentation with casein glues and paints to better understand capabilities and limitations.  It's neat stuff though and was once a common glue and paint base when and where water resistance was required.

Pocket Axe Strop Production Part 1, Introduction, Liming Hides and Selecting Wood

This is part 1 of my project to build up Pocket axe strops from scratch as incentive/rewards for the Axe Cordwood Challenge.  I may also sell some on the website depending on numerous factors.  For those who don't know, a strop is a device for polishing or refining a sharpened edge.  it is the last step in many sharpening sequences and can also be used to touch up edges, especially if polishing compound is used.  It usually involves leather, which my design of course does, but the act of stropping can also be done on wood or even cloth.  In this project, I'm building strops from the ground up, which involves, tanning, glue making and working up some wood from it's raw log-like state.  There should be no materials used in these strops that were not processed by me here on the homestead, down to the lime and fat used in preparing the leather.  The project will span an undetermined number of videos, as well as a short version of making an easy high quality hide glue from scraps that most hunters or butchers of animals typically throw away.  Almost anyone who is not me should learn a lot from this series and I hope to learn some stuff too! ;)  Feel free to vote on names for the pocket strop or think of new ones... Stropet, Pocket Strop-It, Pixie Paddle (the woods are a dangerous place full of mischievious pixies!).

How I Process Deer Legs for Sinew, Skins, Bones, Hooves and Glue Stock

There are a lot of useful parts in the lower leg of deer and similar animals. I've processed many of them over the years while skinning deer for hunters.  When you're faced with a pile of 70 or 80 of the things you have to cut to the chase and giterdun.  Here are a few pointers for the would be leg dismantler.

Quality Hide Glue From Scratch, #6, Part 2, Cutting and Drying

Here ya go.  I just love the way this glue turns out!  It's pretty fun to sit around and sift my hands through it :DWhen I was first taught how to make hide glue it was always a cloudy stinky mess.  Then I started poring through old technical manuals.  Now my glue looks like a pile of little gems.  There will be one or two more installments coming in this series eventually.  Hey, you may not want to make hide glue now, but I'm building an archive here.  Mark my words, the further people are divorced from reality by an increasingly industrialized society, the more artists and craftspeople will tend to go back to the roots of materials and production.  It's already happening more and more, I'm just ahead of my time.  If I can convince even a few woodworkers to make this amazing glue for themselves and use it or one person to go into production to make small batch artisan hide glue, It will have been worth putting out this series.  You can find videos and stuff on making hide glue, but probably none from the ground up with an eye to high quality, but that's how we roll here- top shelf ya'll.  When the zombie apocalypse comes, you won't be able to go to the pet store to get a rawhide chew toy.  And we don't want to let all that zombie skin go to waste!

Quality Hide Glue From Scratch, #6, Part 1, Cooking the Glue

I missed a Saturday video on youtube, but hopefully I'm back on track now.  This Saturday's video is Installment 6 in the hide glue series that I started last year.  I had to divide this one into two videos since it was getting really long and I'm still finishing up.  It may not make sense to people to have two parts in one installment, but cooking, pouring, cutting and drying are really sort of all the same step to me since they have to happen in a short space of time.  Part 2 should be out within a week.  The glue is looking great if I do say.  This batch will be for sale in the webstore starting tomorrow when it will be dry enough to package.

 

 

Video Series on Making Quality Hide Glue

 

I'm shooting a video series on making high grade hide glue.  At least that is the goal, we'll see when I test the glue after it's finished, or maybe have it tested by someone else.  The third video, on liming, is uploading to YouTube as I'm typing this.  The approach is a sort of learn as you follow along kind of thing, going through the process of turning a cattle hide from Tamara's recent cattle processing class into hide glue.  Every time I go to work on the skin, I take some video and edit it down.  One section is sort of a lecture type deal with some chalkboard action, one is on fleshing and, aside from the liming one uploading now, the others will be de-hairing and de-liming, cooking and pouring, then finally cutting and drying.  Maybe at some point there will be one on testing the finished glue.

This hide glue series will be fairly long, but there are things in there to learn beyond making hide glue.  Little snippets about other stuff relating to tanning skins and such inevitably work their way in.  No process is an island after all.  So far these videos have been decidedly lacking in popularity and the total number of people that really get a lot out of this will probably not be that many.  But it will be there when people are ready for it, and that is most of the reason I do this stuff at this point, as a reference archive and so it doesn't all die with me one day.  Personally, I think it's really cool, even though I've so far mostly restrained myself from going on long tangents about multiple related processes and ideas.  Poking around looking at other hide glue videos on youtube, a lot (or most?) of them use rawhide chew toys cut up in pieces.  Nothing wrong with that in context I suppose, but that has never been what we, or the genesis of Paleotechnics, has ever been about.  I'm definitely bringing you something closer to the ground up version.

The link below goes to the main Playlist into which all videos in the series will be placed as they come out.  I think anyone with any kind of google account, like Gmail, can subscribe for updates.  My channel, for now, is a mixed bag of stuff I get up to.  I'm also currently also doing a series on amateur apple breeding, which will follow my progress over the years attempting to breed up some new red fleshed apples here at the Turkeysong experimental homestead.  For the hide glue series,  I'm in the dehairing/refleshing/deliming process now, so that one should be up soon.  When finished, I will probably sell the glue on Etsy.  If that works, maybe I'll add artisan hide glue making to my list of little income sources.  Artisanal hide glue for artisanal artisans, you know instrument makers, fine artists who use traditional materials, fine woodworkers that want their furniture to be fully repairable in the future and the likes of them.  People who are keepin' it real!  See ya...

glue#1thumbFINISHEDYELLOW
glue#1thumbFINISHEDYELLOW

Lampblack, what it is and what it's good for

lampblack header Lampblack is a form of carbon.  You can think of it as something like very, very finely divided charcoal.  Because it is so incredibly fine, a small amount covers a large area giving an intense black color.  It forms the basis of the best traditional black inks and has been used to many other ends from shoe polish to blackening gun sights.  Lamblack’s extreme opacity and complete resistance to fading are excellent characteristics for use in the arts

Lampblack can be made from burning oily or resinous materials, while collecting the resulting soot.  The pitch of pine trees and other conifers make good lamp blacks, as do oils burned with a wick.  It has also traditionally been collected from the inside of oil lamp mantles (the clear glass covering over oil lamps), thus the name.  The trick to producing it yourself is to burn the material in such a way that combustion is incomplete.  When combustion is complete, the carbon is fully burned, but if the flame is interrupted, or just plain inefficient, some of the carbon remains as soot along with other unburned chemicals.  The rising black soot can be collected on a metal plate, bowl or flat stone.

Using a large and lumpy, or long, wick will usually create a lot of soot.  Another way to create incomplete combustion is to interrupt the flame.  You may have noticed that when an object is held in a candle flame, soot results.  When the wick is trimmed or made properly and the flame is burning cleanly, the carbon will be completely burned to up at the tip of the flame and no soot results.  The truth is that it is somewhat challenging to make wicks which do NOT soot!  The modern candle wick is an exception, not the rule.  But for making lampblack, you want a whole LOT of soot, so make that flame as dirty as possible.

Flame interrupted.

A good way to make lamp black under field conditions is to make a small table like arrangement of stones.  Pitch or pitch saturated wood from pine or other conifers is burned under the top plate and the soot brushed off with a feather occasionally.  I have some picture of that somewhere, but they are like that old kind that are on paper...  Any kind of oil lamp arrangement with a plate of some kind on top will also work fine.  A tuna can with the lid left partly attached and bent down to form a ramp into the oil is an easy solution.

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Lampblack is not at all easily mixed with water.  In fact, it is remarkably difficult to get the two together.  One time I was tattooing my friend Wylie’s leg (I have pictures of that somewhere too...) with pine soot and figured out that if I spilled beer into the ink, it mixed easier.  Yay for beer!  It can be mixed with plain water sometimes if a very small amount of water is used, but it can also be almost impossible and a drop of alcohol helps break the surface tension.  Lamp black is much used for tattooing around the world, being much finer than charcoal. I have two small tattoo test spots on my leg made by slicing the skin with obsidian and rubbing stuff in.  The one with charcoal is uneven, while the one with lampblack is much cleaner.  A third made with iron oxide (red ochre, a mineral pigment) is long gone, having faded away completely.

Often lampblack is somewhat oily containing compounds created by the heat destruction of the oil or pitch that are not pure carbon.  The lampblack can be purified to an extent by re-burning it in an oxygen free environment.  If put in a small sealed tin, it can be burned in a fire to clean it up a little.  My results calcining soot this way have been mixed, and I’m unsure whether it is necessary.  Another old book (quoted below) recommends packing into an open ended tube for re-burning.  I'll try that next time.

Asian inks are usually made as a solid stick by mixing lampblack with a small amount of collagen glue made from hides, sinew or especially antler.  The stick is then rubbed up with a little water on a special stone and the ink used immediately.  I hope to do almost all illustrations for paleotechnic’s publications with this type of home made ink, and other home made art materials, from here on out.  Carbon ink works great with a feather quill pen (that'll have to be another post)   What is called india Ink is originally a soot based ink as well, but in liquid form.  Since I lost the last ink stick that I made (someone probably threw it out, because it looked like a fossilized anteater turd, though it was perfectly functional), and have to make another, yet another future post may just have to cover ink making in detail!  For now, you know what lamblack is, and how to make it and you can build from there.  If you just want to blacken your gun sights, or whip up some corpse paint, it's easy to make a small amount of lamp black with a candle or chunk of pitch.  Another brick in the wall of self reliance.

asian shit

I’ll leave you with a couple of quotes from old books scrounged up by using a google books search limited to the 19th century.

Technical Repository, Volume 11  T Cadell, 1827

Black shell-lac varnish.—Shell-lac varnish may be rendered black, by mixing with it with either ivory, or lamp-black. The editor has frequently used, and always preferred the latter. It should not be used as sold in the shops, being then greasy, as the workmen call it, and will neither mix or dry, well. Sometimes the lamp-black contains particles of plaster, from the walls of the chambers in which it is made; this, of course, should be rejected.

To prepare lamp black for use.—Press a portion of it into an earthen or metallic vessel, which may be made red hot in the fire; for small quantities, a tobacco pipe, a piece of a gun-barrel, or any other metallic tube, will answer the purpose perfectly well. It is not necessary to close the vessel, but the powder should be well rammed in; place the whole in an open fire until it is red-hot throughout; this may be known by the lamp-black ceasing to flame at the exposed parts; take it from the fire, and allow it to become quite cool before you remove it from the vessel, otherwise it will burn into ashes. Lamp-black, thus prepared, will mix readily with water, will dry well in paint or varnish, and will be improved in colour.

To mix the colour with the varnish.—Rub the lampblack up with a little alcohol, spirits of turpentine, or weak varnish, taking care to make it perfectly smooth before putting it into the cup with the varnish. To give a good black colour, the quantity of lamp-black must be considerable; this, it is true, will lessen the brilliancy of the varnish in some degree, but a thin coat of seed-lac, will diminish this fault. When only a small quantity of blackvarnish is wanted, it may be made by dissolving black sealing wax in alcohol. Sealing wax being composed principally of shell-lac. But little heat should be employed, or the black colour will be precipitated.

Five Thousand Receipts in All the Useful and Domestic Arts: Constituting a Complete and Universal Practical Library, and Operative Cyclopaedia

A. Small, 1825

Lamp black may be rendered mellower by making it with black which has been kept an hour in a state of redness in a close Crucible. It then loses the matter which accompanies this kind of soot.;

TO MAKE PAINTS FROM LAMP BLACK.

The consumption of lamp black is very extensive in common painting. It serves to modify the brightness of the tones of the other colours, or to facilitate the composition of secondary colours. The oil paint applied to iron grates and railing, and the paint applied to paper snuff boxes, to those made of tin plate, and to other articles with dark grounds, consume a very large quantity of this black. Great solidity may be given to works of this kind, by covering them with several coatings of the fat turpentine, or golden varnish, which has been mixed with lamp black, washed in water, to separate the foreign bodies introduced into it by the negligence of the workmen who prepare it After the varnish is applied, the articles are dried in a stove, by exposing them to a heat somewhat greater than that employed for articles of paper...”

TO MAKE A SUPERIOR LAMP BLACK.

Suspend over a lamp a funnel of tin plate, having above it a pipe, to convey from the apartment the smoke which escapes from the lamp.  Large mushrooms, of a very black carbonaceous matter, and exceedingly light, will be formed at the summit of the cone. This carbonaceous part is carried to such a state of division as cannot be given to any other matter, by grinding it on a piece of porphyry. This black goes a great way in every kind of painting. It may be rendered drier by calcination in close vessels.

The funnel Ought to be united to the pipe, which conveys off the smoke; by means of wire, because solder would be Melted by the flame of the lamp.

Posted on February 24, 2014 and filed under adhesives, decoration and art, fire.

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

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.

*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.

*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.

*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.

*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.

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 &%^%$$#!!!

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.

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.)

Posted on September 7, 2013 and filed under adhesives, Animal Parts.

Hide Glue part I : Meet Hide Glue

about hide glue headerThis is the first part in what will hopefully be a two or three, or even four, part series on Hide Glue.  Very few people are making really high quality glue these days.  The plan is to provide a solid introduction with practical steps to making high quality glue, and to cover the basics of using it.  Following posts will have to wait for time, energy and pictures.  You can subscribe on the right to receive notification of new posts via email so you don't have to stay glued to your screen.

Collagen Glue, aka hide glue or animal glue, is made from the parts of animal bodies which contain large amounts of collagen.  Collagen is abundant in animal bodies, but certain parts are highly concentrated sources of relatively pure collagen of the type useful for making glue.  Commonly used glue materials are skin (including fish skins), sinews (the fibers which connect bones to muscles) and antler.  Fish air bladders have been used to make an especially strong glue.  The common practice of using skin scraps to make glue has given us the term Hide Glue, which is generally used for all collagen glues regardless of the raw material used to produce it.  The materials are cooked long and slow to dissolve the collagen, followed by drying the resulting gelatin which is then reconstituted in water as needed.

There is a misunderstanding that glue is made from hooves.  The horny outer covering of hooves does not contain useful collagen.  Hoof sheaths and horns are more physiologically related to hair and are primarily composed of keratin which does not go into solution when cooked in water.  The bones and ligaments inside the hoof do contain a lot of collagen and have commonly been used to by glue boilers to make glue and neatsfoot oil.  Making glue from the whole lower legs is not generally a good choice for home producers due to contamination from fats and other unwanted substances.  If you try to make glue from the hoof sheath itself, it won't work.  I know, I’ve tried.  Instead, I recommend extracting some of the glue making parts from the lower legs and feet and then using just those, but that is for another post.

The gelatin used in cooking (jello, etc...) is just a refined grade of collagen glue.  Meat stocks that gel on cooling, also do so as a result of dissolved collagen.  Gelatin is a very nourishing food.

Hide glue has many traditional uses.  It is a very strong glue when well made and properly used.  Hide glue always remains water soluble, meaning that the joint will come apart if the glue reaches a certain moisture content.  As one can imagine, the water solubility of hide glue is often inconvenient and is one of the major factors in it’s replacement by modern moisture resistant glues.  Although sometimes inconvenient, hide glue’s water solubility can be an advantage.  It is still used in making fine musical instruments and by a few forward looking fine furniture makers, because the item can be completely disassembled with the application of steam to the joints.  Easy disassembly allows for repair without incurring any damage to the wooden parts.  Imagine the crime of repairing some amazing 300 year old violin using a permanent glue.  It would be severely damaged a hundred years from now when it requires repair again.

This old desk top is hide glued.  It was left in the rain and delaminated readily when wet.  If wetted evenly whole sheets could be pulled off of it.

Aside from water solubility, another factor in the replacement of hide glue by modern glues is the inconvenient fact that it must be used while hot.  Glueing up projects may be stressful even with modern glues, requiring speed and accuracy, but working with hide glue is much more exacting.  The glue should remain liquid until the joint is set and clamped, which means that it must remain warm.  Unfortunately, it is not advisable to apply hide glue to hot wood in order to keep the glue warm, because it can cause the wood to absorb all the glue.

The final blow to hide glue in modern industry and arts is that it does not store well in it’s wet state.  The old glue must be thrown out frequently and a new batch prepared.  Rotting glue loses it’s strength rapidly.  Attempts to make preserved hide glues that could be stored in a ready to use state have been made, but results have never been quite up to the traditional product.  So, real hide glue is just not convenient.

One other place where hide glue has retained some use is in the arts for sizing and gilding with gold leaf.

In paleotechnology, hide glue has many uses and is the strongest glue that we can make.  It is used to hold sinew wrappings in place, to size over paintings, as a binder for paint pigments, to glue materials together, and to glue the sinew backings or other coverings onto bows.  Making fine quality hide glue is well within the means of homescale technologists like you!

RECAP

Making: Hide glue is produced from Collagen sources in animal bodies such as skin, sinew and antler.  Accomplished by dissolution into hot water by long cooking, followed by drying the resulting gelatin and then reconstitution in water.

Advantages of hide glue:  accessible (you can make it!), easy to make, strong, easy repairs, nontoxic.

Disadvantages of hide glue:  must be used rapidly before it cools and jells, joints come apart when moist, glue rots easily once made.

Posted on July 20, 2013 and filed under adhesives, Animal Parts.