May 14, 2014 at 9:12 am #13726
Tanning is a subject with much confusion and jargon, I want to see if I can make it easier!
What is Tanning?
Tanning is the process of chemically (and/or mechanically) altering a piece of skin to turn it into leather or a fur.
How do i start?
1. First, get a skin – any skin!
2. Scrape all of the integument, fat and muscle off the inside of the skin (this is also known as fleshing).
3. (Optional) If you can’t process the skin at this stage you can salt it and dry it to process later. This is done by covering the skin side of the hide with an inch of any kind of salt and leaving it to dry. If you do salt a hide, you will have to soak the salt out later for the tanning process to work effectively.
4. Decide if your aim is a fur or leather. If you want a fur, proceed to one of the tanning methods below. If you want leather then you need to bate your hide. Bating is the process of removing the hair from the hide and can be done in one of two ways; leave it to bacterialy decompose a little in some water until the hair slips (comes loose), or use an alkali. It goes without saying that the first way stinks, literally, and it is fairly likely to weaken you leather or even ruin it unless you are a perfect judge of timing an decomp!
The alkali path is easiest, least stinky and best for the leather. A mild caustic soda solution for 12-24 hours (longer in cold weather) is sufficient to make the hair, and upper dermal layers of the skin slip and easy to scrape off.
Caustic soda’s scary stuff i hear you say! Damn Straight! The easiest and safest way to make sure you don’t harm your self is to mix ash and water and let it settle to leave lye (a [relatively] mild caustic soda solution) on top. Try a KG of hard wood ash to 20L of water but YMMV depending on your ashes. It should make your fingers feel slightly slippery when it wets them (or more safely, be strong enough to float a fresh egg).
5. Neutralize your hide – you just used caustic to bate your hide and cause hair slip, so now neutralize it with a bit of vinegar and water in a bucket – wring it out and really push the vinegar water through your hide until it feels less slippery. Note: if you used anything bigger than a rabbit skin you will notice just how damn heavy a wet skin is! This is why tanner are strong and cow hides are often cut in halves or quarters!
Congratulations! You are now ready to start tanning!
What do I use to tan a hide/fur?
There are three main kinds of tanning that can be done:
- Brain tan / Buckskin
- Chemical tan
- Vegetable tan/ tanbark tan
Brain tanning involves working an emulsion of fats/oils and water into a scraped hide. Then staking (rubbing twisting and generally stretching the living daylights out of a hide or fur as it drys to make it soft and flexible). This is the best option for tanning furs in a grid down situation. Just be aware that if something brain tanned gets wet you have to oil it and work it as it drys out, or it will become as hard as a brick! One way to overcome this problem is to thoroughly smoke the fur or leather over a soft wood fire till it is a rich brown colour; if this is repeated every year then it will impart a measure of water resistance and help to keep the hide supple.
Gypsy Wanderer has a great write up of this process over here:
Chemical tanning is probably the least useful of these three methods for preppers; it relies on industrial chemicals, some of which are rather toxic.
Once you have prepared your fur or hide it is soaked or dry rubbed with combinations of Alum and/or chromium compounds then is dried and staked to make it supple.
I wont give any more details here as I have never used this method, it is not sustainable and it is toxic.
‘Vegetable’ tanning it useful for making strong leather, and is the kind of tanning that truly gives tanning it’s name. It relies on the ‘tannins’ (tannic acid and some other vegetable compounds) from vegetative material (usually tree bark of some kind) to chemically affect the strings of proteins than make up the skin, tightening them and rendering each fiber ‘slippery’ and able to flex and move when dry (after staking the hide while drying).
You can dry tan by burrying your hides in a pit with alternating layers of ‘tannage’ (dry powdred bark and vegetable material that contains tanning) and pressing them, or you can wet tan.
Wet tanning is the most reliable vegetable tanning method. It relies on soaking and/or boiling bark twigs and leaves that are high in tannins to extract the tanning and then immersing the hides in the cooled liquid.
with this process it is important to start with a weaker tanning solution and add more progressively over time.
The reason for this is that tannins physically shrink the fibers that make up the skin and if you use too strong a solution straight away the skin is ‘cased’ or ‘case hardened'; the outer layers become impermeable to the tanning liquid while the center remains untanned and will eventually rot!
Slowly increasing the strength of the tanning solution allows the tannins to penetrate completely to the center of the hide.
Great! How do i find ‘vegetable tan’ when TSHTF?
Now this is a rather lovely bit of fun! You could look up a list of trees that contain useful levels of tannin and find which ones grown in your area and how to identify them . . . or you could experiment!
Tannin hunting method 1: the tongue test!
Tannins are the things that make your mouth pucker up and tongue feel ‘furry’ – like when you bite into an unripe persimmon. You can grab your field guide, figure out which trees ARE NOT POISONOUS and try a nibble of them – if they make your tongue fur and mouth pucker, it’s got tannin!
Tannin hunting method 2: the machete test!
Take a machete (or knife) made of good carbon steel and polish it back to bare shiny metal. Chop into your prospective tannin tree for a few minutes so the blade gets good and damp from the plant’s juices, then set it aside to dry for a little while. If you notice blue/black stains on the blade that is iron-tannate and a good indicator.
Tannin hunting method 3: the scientific method!
Find (garden centers) or make some ferric-sulphate (iron disolved in sulfuric acid and dried out and crystallized) This should be a pale greenish colour.
Boil up a sample (powdered or broken bark is ideal) of something you think will contain tannin and strain it into a small, clean, clear glass container label it with the source and stir in a bit of ferric-sulphate. Leave it for a few hours and look for blackish/blueish sludge that is Iron-tannate; the indicator of the presence of tannin in the vegetation you boiled.
OK, I skinned, fleshed, bated, de-haired, neutralized, found tannin and have a skin that’s brownish (tanned) the whole way through. It’s wet, heavy and a pain in the ass, what now?
For sole leather (leather you want hard for using in the soles of shoes or boots) you are done – it will dry hard and you can oil it and it is ready to use.
For Garment leather (any leather that needs to flex/feel soft when it’s dry and finished) it is CRUCIAL that you don’t let the leather dry out while you are working it over a stake or ring to soften it (staking it) until it is feeling soft all over, if you do you will have to soak it in water and start again (this is sometimes called breaking the hide).
As each part of the hide is properly worked, it will turn paler and more flexible. Keep working all parts of the hide until soft and dry.
At this point it is a good idea to oil the hide; Neat’s foot oil or another (well rendered) animal based grease or fat is ideal for this. Once the fat is thoroughly worked in you can scrub the hide with dry sawdust (or similar) to remove any surface grease. [Optional at this point is smoking it like buckskin, but not really needed].
Congratulations! Your leather is now finished and ready to use! At this point it can become a bit wet and should remain pliable even when it dries out.
Ok I made leather, but what’s this rawhide stuff I heard about?
Rawhide can be useful stuff. It is basically what you have after fleshing, bating, neutralizing and de-hairing your hid. When wet it is very pliable and stretchy – you can make it into virtually any shape, when it dries it dries rock hard and shrinks (to the point that some gangs were known to kill be wrapping a victim in raw hid and then leaving it to dry crushing them to death.
It is useful for lashing spear heads on to hafts, making boxes, baskets and cases that will be painted or varnished and other applications where it wont get damp again. In a survival situation you can even boil water in a rawhide pot (punched and strung round the top); the water inside stops it burning through.
This has been written off the top of my head and any mistakes or errors are my own – feel free to point them out and i’ll fix them right upMay 14, 2014 at 3:17 pm #13759
Awesome tutorial! I was tanning a deer while doing a primitive survival course a while ago. Pretty interesting experience. I’m looking forward to tan rabbits once we get them in the coming months. Not sure how happy my wife is about the whole process but she does like to work with some fur, just maybe not when she sees where it is coming from.
Anyway, I think processing animals and then working with their remains is something everyone should have done at least once.
Alea iacta est ("The die has been cast")May 15, 2014 at 2:04 am #13827
Brain tanning involves actually using the brain. It is interesting to note that exactly one deer brain is just enough to treat one deer hide – almost as if God intended it that way.
Trees that have lots of tannin in them are walnuts and oaks. It is interesting to note that walnut shells, I believe, have loads of tannin in them. If I remember rightly, you can boil crushed walnut hulls to get a mixture high in tannin… wait, let me look this up… I actually have a book… be right back…
The book I have is The Complete Book of Tanning Skins and Furs, by James E. Churchill.
The book says the best trees to use for high tannin content are Hemlocks and Oaks. Grind up 16 ounces of bark per each pound of skin. Simmer bark for 3 hours or steep in warm water for 48 hours, like tea. He doesn’t mention brain tanning or walnut hulls.. perhaps it’s in another book of mine. I will have to update this.
Still, the book is an outstanding reference. Even teaches how to turn hides into robes, gives patterns for mocs and directions on how to build a breaking bench, fleshing beam, tanning bench and other various tools…
One thing it does not do is teach how to make parchment. Sheepskin parchment. The stuff, so long as it is protected, will last for… well, ever, I think… we have sheepskin parchments that are many hundreds of years old, with many over 1000 years old, and they’re just fine…
Edit: Forgot to tell you, that was an excellent tutorial, Fro… nicely done.
The wicked flee when none pursueth..." - Proverbs 28:1May 15, 2014 at 6:58 am #13840
Cheers on the info of weights of tanning material to skin – useful numbers to have.
I was a bit mental learning to do this, having brain tanned a rabbit, i then went and vege tanned a sheep skin (minus the wool) – it was a pig to do, a great learning experience, and i got useable leather out of it!
Re: brain tanning, Yep – “each animal was given just enough brains to tan it’s own hide” i believe the saying goes. For those that are squeamish, egg yolks can be used, Ive even heard of a version that use homemade lye soap and neat’s foot oil. Basically, any emulsion of fat and water will do the trick.
Top tan bark trees: Oak sp., acacia sp., camellia sp. (they are what is used to make tea! – think of the black tanning inside a metal teapot!) Birch, alder, fir, Sumac, chestnut.
There are actually two kinds of tannin which impart slightly different properties to the finished leather. This guy explains it better than i do
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