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Making your own utility leather
There's a lot of interest in making leather and making products for sheaths, and holsters.. lots of things. But where does that leather come from?
Likely, you got it from a store, who got it from some industrial tannery, that uses chemicals and produces massive amounts of waste and pollution. It is likely stiff, or greasy, or rubbery and not very "natural" feeling.
How would you like to make your own leather from things you probably already have around the house? You can do it with natural materials that will return to the earth naturally. This is somewhat of a lost art in today's "I wan't it now" society.
I am no history expert, but I think it's safe to say that skin is probably the first thing our most ancient ancestors ever wore for coverings. Very likely they found some carcass and discovered the warmth provided by the fur of the critter. The earliest skins were very likely un-tanned, sloppy, stinky, stiff, hideous creatures to behold. Most of what we know about tanning was (like most other things) discovered by accident. With a whole lot of trial and error (and more the latter) the art was perfected to a science.
This post is intended to be a primer on skin so that you understand what we will be accomplishing with bark tanning. I will touch on the bark for now but will hopefully as the post progresses and other tanners contribute, have more information.
There are also different types of tanning that produce different types of leathers. Buckskin is a soft wearable leather that is washable, comfortable, stretchy, and durable. It is soft and supple.. not something you want to carry a sharp object in.
Furs are utilizing the animals hair as a layer of insulation, or as decoration. They are treated totally different from buckskin and produce a different quality of leather.
We are going to be talking about what I call "utility leather". the tight-grained tough abusable leather that you guys use for sheaths and boots.
So lets get the skinny...
the attached picture shows the layers of the skin. it is composed of 3 main layers. the primary ingredients are collagen, protein strings that comprise the fibers, and mucus, mostly made of hydrogen-based compounds. It is the organ responsible for keeping out bad stuff, and keeping in good stuff. A little bit more about skin and we'll move on.
The outermost layer of skin is simply dead epidermal cells, filled with keratin, that provide the initial barrier for external harm. scratch your arm and you'll see it flake off. The epidermis has 2 layers. the inner layer is living cells that reproduce simply for the function of dying to make an new outer layer (more research may prove more uses).
The middle layer of the skin is called the dermis, and contains all the living tissue and most of the fibers we will be working with. It contains the hair follicles, sweat glands, etc.
The main thing we notice here is that the epidermis and dermis have no clear definition of separation. they fit together like egg crates.
The inner layer of skin we call the membrane. It is mostly mucus and serves the purpose of allowing the skin to move freely across the muscles and bones without much stretching or tearing.
We will be working with the outer two layers, the epidermis, and the dermis.
Furs leave the whole skin intact, hair and all. This is outside the scope of what we are trying to accomplish so we'll leave that for another time.
Buckskin utilizes the dermis. By removing the tight-fibered epidermis (grain layer) and the loose fluffy membrane layer, you are left with a very fibrous dermis. Hereforth I will call it the "fiber network" or the "network". Buckskin is much more involved than the scope of this article, so we'll leave it out too.
Grain leather, on the other hand, is much less work than buckskin, and only a little more work than a fur. you can handle it pretty roughly and when it's done it's super tough. For grain leather, you utilize the epidermis to be the shiny outer surface, often textured, and the fiber network which is the bulk of the leather. This is what we typically call "Leather".
In bark tanning, you make use of tannic acid which tightens the skin, shrinks it and makes it much tougher than buckskin or fur. The astringency of the bark liquor keeps the skin from rotting, prevents bacterial decay, and keeps it "clean" (although you might disagree once you smell year old bark liquor). To my knowledge the only thing that can grow in bark liquor is mold, which floats on top (not submerged) and feeds off the sugars in the liquor. We call it liquor because it actually does ferment, getting a sweet, pungent cider flavor. Vinegar is acidic, so is bark liquor, and the fermentation only provides more acids.
additionally there are mineral "stains" in the bark that color the skin.
Is that enough to absorb at one time? wait.. I have a little more to say..
To do bark tanning, you will need a few things that you probably already have.
Bark source from a tree that is high in tannins. There are fruits that are high in tannic acid as well, like hickory nut hulls, though I have no experience with that. I use laurel oak, which we cut for firewood.once a tree is cut it will no longer produce tannic acid (logically). It is imperative that you keep your bark source DRY. Water will leach out the tannins and your bark will be of no use.
Wood ashes to make a lye solution. My ash source and bark source are the same. you can use hydrated lime in a pinch. It's called "pickling lime" at the grocery store. It's chemical name is Calcium Carbonate or CaCO3.
A container to boil bark in. Do not use metal containers with exposed surfaces or rust. It WILL turn your liquor black. Ceramic coated cookware or enamelware is the best to use, although you use what you have.
A bucket with a lid to store the hide in while it tans.
A container to store extra liquor in. It will take several doses throughout the process to keep the strength of the liquor up.
a wood dowel, a drawknife (dull), or piece of flat metal for cleaning the skin. The hair and membrane are removed for grain leather.
of course, you need a skin to tan
there are a few other things you might need along the way and we'll cover those as we get to them.
now a brief rundown on the process, and I'll let you take a break.
The skin is prepared by fleshing, then bucking in lye solution, then mild scraping, and rinsing out the alkali
The bark is prepared by removing from the log and boiling.. pretty straightforward.
the bark liquor is mixed and diluted.
put the skin in and wait..
curry, or "dress" the skin.
enjoy
thats all there is to it, and when I get more time, I'll post up details about each of the steps involved. Most of which will deal with the skin itself. So .. when you are out cutting firewood, take your tree ID field guides and locate one that is high in tannins. Chinkapin Oak was the original bark tan in the US valued for it's high tannin content and beautiful tan color.
I posted before about proper skinning, so if you don't have a skin, you should be able to offer a hunter a free skinning in exchange for the skin. My knowledge only encompasses deer skin due to it's availability to me. Cow hides take considerably longer to tan, and smaller animals are so thin that I haven't warranted any use for "thin leather". I prefer to keep the hair for furs on smaller animals.
Ok I'm done.... For now!
More coming soon!!
Bucking solution and hide prep.
So, you got yourself a nice clean skin from a hunter or game processor. Now you have to do a little prep work. get ready to get nasty.
Grab your rubber gloves, and plastic apron. Get your fleshing tool, i.e. draw knife, bone flesher, or metal bar. You will need some sort of scraping beam to lay the skin over to remove the chunks of meat and fat from the skin.
Here are my tools: top to bottom, modified draw knife, push-plow I made, wood dowel for squeegee, and a bone fleshing tool from a deer leg.
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for the moment, the best pic I have is one of the butchered hides with gashes all in it to show the beam.
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This is a 6" irrigation pipe, and you'll notice in the background I have a smaller 3" pipe which allows more lbs of pressure to surface contact area.
For now you don't need to get all the slimy, stringy membrane tissue off, just the meat and fat. In a few days it will all come off super easy.
now you have a skin that is meat free, and mostly fat free. It's time to buck it in a bucket (lol). The purpose of bucking is to swell the hide, remove the ground substance, and free the hide of hair easily. Buckskin uses this to do all the above but includes the removal of the epidermal layer. We want the epidermis (grain) to stay on ours.
In your bucket you need to add about 2 gallons of cleaned hardwood ashes to about a gallon of water. Charcoal in the ashes will stain the skin so you should pre-clean your ashes through window screen or whatever you have. get all the big chunks of char out. the little ones will float to the top later and can be skivved out.
Give it a good stir and wait for the ashes to settle. Drop in a brown chicken egg and it should be suspended in the solution. Not floating on it's side on top, and not sinking to the bottom. This is a specific gravity test and I won't pretend to know why it works, but at a certain pH range, the egg will have a surface exposed that is the diameter of a half dollar. If you have this, your bucking solution is "just right".
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pH paper is not accurate enough to test this. Your pH should be right around 13.0 which is very alkaline. 13.0 is ten times as concentrated as 12.9 and pH strips will only tell you that it is 12.x... somewhere between 11.0 and 13.0. This just isn't accurate enough to clean the mucus from the interior of the network.
A little redneck science here.. Your bucking solution is now liquid lye. that means it is a "hydroxide" or OH-. It lacks a hydrogen atom to become a stable molecule, aka water. OH- ions really want to balance out and not be negative ions, so they steal a H atom from the mucus in the skin.
Mucus, as gross as it sounds, is the stuff we are all made of. We, in tanning, call it the ground substance: what makes a thing rot and return to the ground. By removing the mucus, you have changed the chemical characteristics of the skin. It is necessary to remove the mucus because it is what inhibits outside harmful substances from entering our bodies. We want to bind tannic acids to the collagen fibers (protein chains) in the network and grain which is next to impossible with mucus in the way.
If your buck is too weak, the egg will sink; add more ashes, stir, and test again. If it is too strong, the egg will float to the top, and lay over on it's side; add more water, stir, and test again.
Once you have it "just right", submerge the hide in the buck. WEAR GLOVES! THIS IS ACTUAL LYE AND WILL BURN YOUR SKIN! Use a rock, or a couple bricks to weigh the hide down in the ashes, make sure the whole hide is completely covered. put the lid on and wait. Hide with hair on will float because the deer's hair is hollow.
You will know your hide is done bucking when you can RUB THE HAIR OFF WITH YOUR FINGERS. It is imperative that the hair come off effortlessly, I mean, you can almost spray it off with the waterhose. during your wait, you will need to monitor the hides progress. Stir it once a day at least, twice if you have time, as OH- ions will be used up close to the skins surface and in order to get more H mucus out, it will need to move around to a higher concentration.
Once the hide is completely done bucking (the hair sloughs off), you will be ready to use your wood dowel or other tool to finish removing the hair. Be careful not to bust the grain when doing so. It is most noticeable on the belly and armpits of the hide where the network is thinner and the grain is not attached so rigidly. Use care and you won't bust the grain.
With the hair removed, you can easily finish membraning. put a towel over your beam to cushion the grain so it isn't damaged and go to your metal tool and scrape deeply on the flesh side of the hide to remove as much of the loose stringy membrane as possible. If you don't get it all, don't worry. With the mucus removed, particles (tannins) can move freely from flesh side toward grain side, as they would naturally if still on the critter. Still be careful that you don't bust the grain by using too much force on the flesh side. I've done this, not paying attention so it can happen!!
With the bucking done and the hide cleaned, you now have to wash out the lye. This rinsing step is necessary to bring the hide back to a neutral pH. If you don't have running water nearby, I suggest you relocate. put the hide in a bucket and leave the hose trickling in the bucket (or weigh it down in a stream with rocks). The excess lye ions will move out of the hide and it will return to a pure white color. If it is still brownish (tawny) It needs to rinse more. It should not feel rubbery or slippery, but be stretchy and have a "grip".
your skin is now ready to be bark tanned. during all the wait time, you will need to be getting your bark together. I'll talk about the bark in the next post but for now, let me just say that this is the hard part. It works on a surface area scale. the smaller the bark particles, the more tannins you will extract at a time. but thats another post.
In summary, you are preparing the skin for tanning, by removing unwanted chaff (hair and membrane), AND THE GROUND SUBSTANCE, MUCUS. The whole ordeal should only take a few hours, not counting bucking time which is typically 3 or 4 days depending on temps. time spent frozen does not count. I find that above 80 degrees, you can quickly get into decay.. I lost 2 hides like that over the summer.. the best range of temps is between 50 and 70 degrees in my experience.
More coming soon!!
If anyone has any questions about what I've covered so far ask away!
Thanks H63 for pointing out that deer don't have sweat glands. I forgot to mention that ;)
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Preparing the Bark Liquor
Up to this point, we've dealt with the hide itself. While you are waiting for the buck to take it's toll on the ground substance, you can work on getting your bark liquor ready.
There are many, many sources for tannic acid. A little research shows that in settled America, Chinkapin oak was the most widely harvested for making bark tanning liquor. I personally use laurel and live oak. They are very rich in tannins, sugars, and mineral stains. I like the nice deep browns and reds. Many people use Staghorn sumac leaves. Most leaves do contain tannins and this is what makes "brackish water" that you see in stagnant ponds.. it's the dark colored water, stained by tannins leeching out. Other tannin rich sources are acorn hulls, hickory nut hulls.. possibly pecan, this is something I'm going to be trying in the near future.
This is where your tree identification skills will come into play. In your searching and identifying of trees make notes of the ones indicated in your literature that say they contain lots of tannins.
We mostly burn oaks of different species and some have higher concentrations than others. this is my source of wood ash, and bark.. firewood! The key factor is keeping the bark dry. If it rains on it repeatedly you will be left with no tannins or sugars in the bark to tan with, so it is critical to either remove the bark from the logs and store it, or keep the logs covered until you intend to use it.
I use an axe, or hand axe, or machete for the whole process, which is really very simple.. Remove the grey, scaly, outer bark, you will see the inner bark. It is very fibrous, often colored. It is between the outer bark and cambium, which is right next to the grain wood. The attached picture shows the different layers. Tree bark functions much like our own skin, working in layers. The inner bark is the second line of defense, behind the outer bark, to stop insects and such from getting into the heart of the tree. The tannic acid and other astringent materials contained in there are responsible for stopping intruders.
With the outer bark removed, which isn't absolutely necessary, you can see the very fibrous inner bark and cambium. These are best scraped off with a draw knive, or similar device, and shredded or crushed. Extracting the tannic acid and sugars works on a surface area principle.. it comes out quicker the more surface area is exposed. To tell you the truth.. since we are boiling it completely submerged in water, I just dont think it makes that much difference. I crush it into small chunks, and leave the outer bark on most times.. everything works just fine.
This pic shows mid-process.. removing the outer, exposing the inner to be shaved off.
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*Handling the inner bark of the wood WILL stain your hands and make the skin tight. It won't hurt you, but it kinda freaked me out so I thought I'd warn ya!
You are going to need roughly 5x the dry weight of the skin in dry bark. A dry skin weighs somewhere around 3 lbs (just a guess) so I work out about 15 lbs of dry bark for boiling.
Once you have your bark, you need a container to boil it in and a few containers to store it in. I like the 1 gallon pickle jars because it gives me a fairly accurate measure. I use an enamelware pot that holds about 3 gallons (I guess), fill it 3/4 of the way with the crushed bark, add enough water to cover and let it boil for about an hour. pour off the liquid through a cheesecloth or piece of window screen and boil a second time. The second pouring will be slightly weaker than the first. If this is your first liquor, I recommend boiling the bark one more time to get a really weak solution, which will be diluted.
This is what laurel oak liquor looks like in the pot
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Using your third pouring, which should be roughly a gallon of liquid, add this in a bucket with a lid to 2 gallons of water. DO NOT USE MINERAL WATER AND IF YOU HAVE HARD WATER FROM YOUR WELL, EXPECT COLOR CHANGE. Iron WILL turn your liquor black, so blood stains in your hide will be very dark. care should be taken to remove as much blood stains from the hide by repeated rinsing, washing with soap, and squeegee-ing.
Now you have a very weak bark solution to dip your hide in. It should stay in the weak liquor for 5-10 days, sometimes longer if it's really cold. time frozen does not count. When you check it, notice the color of the liquor. It should consistently LOSE color INTO the hide.
Everything in nature seeks balance. water will move from the hide, into the liquor, and the tannins and stains in the liquor will move into the hide until the concentration IN the hide is the same as that of the liquor surrounding it.
When the liquor becomes weak, add your second pouring and another gallon of water.
*a note here. I check my bark liquor once every 2 days to start, then once a week, moving to longer and longer times until I think it is almost ready.
I stuck this hide in the weak bath long enough to come inside, grab the camera, and take the picture, and you can clearly see where it took color instantly. Of course it takes much more time to get color all the way into the interior.
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When the second batch becomes too weak, add in the FIRST pouring. This is a maximum strength pouring, going into a diluted solution. It may be necessary to have a second bucket for this batch. I have 2, one for a weak bath, and another for a strong bath. Traditionally, tanneries used huge vats and would do many hides at once, moving in stages from vat to vat, usually 10 or 12 times before reaching the final bath and striking through.
The reason we are doing the bathing in increments is a phenomena called "case hardening" where the outer surfaces of the skin become so tight that the tannins cannot move further into the interior of the skin. this leaves you with skin that will rot! It is better to move slowly (over a few weeks) to a strong enough bath to tan the interior so that the tannins reach all the way through. This is what we call "struck through".
remember, we had a clean "white" skin. If you make a small cut on the neck (the thickest part of the hide) and it has turned color, it is struck through. My liquor is red and the interior of the hide turns pink. It helps to have a good light to be certain that the hide is struck through.
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Certainly at some point the sugars and acids in the liquor will begin to ferment. This will produce more inane acids that help tighten the skin and further "re-nature" it. It should not smell rancid, but rather sweet and pungent, like fermenting wine. Mine smells more or less like the bark itself, but with a sweet-cider pungency. The astringency of the liquor will prevent bacteria from building up so it's safe to stick your hands in, and probably is good for little nicks and cuts you might have, but it WILL stain your hands!!
To my knowledge, the only thing that can grow in the bucket is mold, which will float on top. It is a product of the sugars fermenting and can be skimmed off, or stirred back in (which is what I do). It's fine for mold to be in the bucket.
If at any time the hide or liquor starts smelling RANCID, then your liquor was either too weak for too long, the bark was not as good as it should have been, OR the temperatures were much too high, i.e. above 80 degrees.
It may be necessary to make more bark liquor to add to the strong bath for really large hides or those that are particularly thick. I like to put bark chips straight into the bucket with the hide when it is very close to being struck through just for good measure.
Here is a piece I did last year, before the currying stage.
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The reason bark tanning works, is that we are working with ionic molecules, and we are manipulating the "nature" of the hide.
By bucking the hide, we remove H atoms from the protein (collagen) molecules (de-naturing). Tannic acid has an extra H atom and binds back to the H receptor on the collagen fibers. It will do the same thing to your liver if you eat too many acorns or other things that are high in tannic acid. We are forcing the binding of molecules that are naturally attracted to each other anyway, we are just doing it in a controlled process.
I'm writing this information from memory and experience. If I've skipped anything or left anything out, please bring it to my attention and I will ammend the post. It's a lot to remember, and it's certainly a lot to explain.
The next post will cover currying, texturing, and finishing your bark tanned hide.
at this point, I would like to hear from others who have experience bark tanning about what trees or other ingredients they use for their bark tan. I have read about using sumac berries for tanning, but have yet to try it, so anyone with any experience in this area is welcome to chime in!