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TEOMCROTE = TEOTWAWKI on steroids! The End Of Mankind's Current Reign Over The Earth takes into account that our ancestors were neither suicidal, stupid, nor our genetic inferiors but still wound up getting wiped off the Earth. Whereas CSER [cser.org: Centre for Study of Existential Risk] tries to PREVENT this dispensation from coming to an end, TEOMCROTE works from the eventuality/possibility/probability that the end our age takes place and what to do then

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tanning/making leather


Skins typically arrived at the tannery dried stiff and dirty with soil and gore. First, the ancient tanners would soak the skins in water to clean and soften them. Then they would pound and scour the skin to remove any remaining flesh and fat. Next, the tanner needed to remove the hair fibers from the skin. This was done by either soaking the skin in urine, painting it with an alkaline lime mixture, or simply allowing the skin to putrefy for several months then dipping it in a salt solution. After the hair fibers were loosened, the tanners scraped them off with a knife.

Once the hair was removed, the tanners would bate the material by pounding dung into the skin or soaking the skin in a solution of animal brains. Among the kinds of dung commonly used were that of dogs or pigeons. Sometimes the dung was mixed with water in a large vat, and the prepared skins were kneaded in the dung water until they became supple, but not too soft. The ancient tanner might use his bare feet to knead the skins in the dung water, and the kneading could last two or three hours.

It was this combination of urine, animal feces and decaying flesh that made ancient tanneries so odiferous.

Children employed as dung gatherers were a common sight in ancient cities. Also common were "piss-pots" located on street corners, where human urine could be collected for use in tanneries or by washerwomen. In some variations of the process, cedar oil, alum or tannin were applied to the skin as a tanning agent. As the skin was stretched, it would lose moisture and absorb the agent.

Leftover leather would be turned into glue. Tanners would place scraps of hides in a vat of water and let them deteriorate for months. The mixture would then be placed over a fire to boil off the water to produce hide glue.

A tannery may be associated with a grindery, originally a whetstone facility for sharpening knives and other sharp tools, but later could carry shoemakers' tools and materials for sale.

CuringPreparing hides begins by curing them with salt. Curing is employed to prevent putrefaction of the protein substance (collagen) from bacterial growth during the time lag that might occur from procuring the hide to when it is processed. Curing removes excess water from the hides and skins using a difference in osmotic pressure. The moisture content of hides and skins gets greatly reduced. In wet-salting, the hides are heavily salted, then pressed into packs for about 30 days. In brine-curing the hides are agitated in a salt water bath for about 16 hours. Generally speaking, curing substantially reduces the chance of spoilage by bacteria. Curing can also be done by preserving the hides and skins at a very low temperature.

In a process known as soaking, the hides are then soaked in clean water to remove the salt and increase the moisture so that the hide or skin can be further treated.

Tawing is a method that uses alum and aluminium salts, generally in conjunction with other products such as egg yolk, flour, and other salts. The leather becomes tawed by soaking in a warm potash alum and salts solution, between 20°C and 30°C. The process increases the leather's pliability, stretchability, softness, and quality. Adding egg yolk and flour to the standard soaking solution further enhances its fine handling characteristics. Then, the leather is air dried ("crusted") for several weeks, which allows it to stabilize. Tawing is traditionally used on pigskins and goatskins to create the whitest colors. However, exposure and aging may cause slight yellowing over time and, if it remains in a wet condition, tawed leather will suffer from decay. Technically, tawing is not tanning.[10]

Depending on the finish desired, the hide may be waxed, rolled, lubricated, injected with oil, split, shaved and, of course, dyed. Suedes, nubucks etc. are finished by raising the nap of the leather by rolling with a rough surface.

The first stage is the preparation for tanning. The second stage is the actual tanning and other chemical treatment. The third stage, known as retanning, applies retanning agents and dyes to the material to provide the physical strength and properties desired depending on the end product. The fourth and final stage, known as finishing, is used to apply finishing material to the surface or finish the surface without the application of any chemicals if so desired.

Liming process of hides and skinsAfter soaking, the hides and skins are taken for liming: treatment with milk of lime (a basic agent) that may involve the addition of "sharpening agents" (disulfide reducing agents) like sodium sulfide, cyanides, amines etc. The objectives of this operation are mainly to:

- Remove the hairs, nails and other keratinous matter
- Remove some of the interfibrillary soluble proteins like mucins
- Swell up and split up the fibres to the desired extent
- Remove the natural grease and fats to some extent
- Bring the collagen in the hide to a proper condition for satisfactory tannage
The weakening of hair is dependent on the breakdown of the disulfide link of the amino acid called cystine, which is the characteristic of the keratin class of protein that gives strength to hair and wools (keratin typically makes up 90% of the dry weight of hair). The hydrogen atoms supplied by the sharpening agent weaken the cystine - cysteine molecular link, and the covalent disulfide bond links are ruptured, which weakens the keratin. To some extent, sharpening also contributes to "unhairing," as it tends to break down the hair proteins.

The isoelectric point of the collagen in the hide (this is a tissue strengthening protein unrelated to keratin) is also shifted to around 4.7 due to liming, which is an acidic type of tannage.

Unhairing agents used during liming are: Sodium sulfide, sodium hydroxide, sodium hydrosulfite, , calcium hydrosulfide, dimethyl amine, and Sodium sulfhydrate.

The majority of hair is then removed mechanically, initially with a machine and then by hand using a dull knife, a process known as scudding. Depending on the end use of the leather, hides may be treated with enzymes to soften them in a process called "bating." But before bating, the pH of the collagen is brought down to a lower level so that enzymes may act on it. This process is known as "deliming."

Once bating is complete, the hides and skins are treated with a mixture of common (table) salt and sulfuric acid, in case a mineral tanning is to be done. This is done to bring down the pH of collagen to a very low level so as to facilitate the penetration of mineral tanning agent into the substance. This process is known as "pickling." The common salt (sodium chloride) penetrates the hide twice as fast as the acid and checks the ill effect of sudden drop of pH.

Vegetable tanning
Vegetable tanning uses tannin (this is the origin of the name of the process). The tannins (a class of polyphenol astringent chemical) occur naturally in the bark and leaves of many plants. Tannins bind to the collagen proteins in the hide and coat them causing them to become less water-soluble, and more resistant to bacterial attack. The process also causes the hide to become more flexible. The primary barks, processed in Bark Mills and used in modern times are chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle (acacia; see catechu), and myrobalan. Hides are stretched on frames and immersed for several weeks in vats of increasing concentrations of tannin. Vegetable tanned hide is flexible and is used for luggage and furniture.

Mineral tanning
Prior to the introduction of the basic chromium species in tanning, several steps are required to produce a tannable hide. These steps include scudding, or removing the hair, liming, or the introduction of alkali agents such as sodium hydroxide, deliming, or restoring neutral pH, bating, or softening the skin with enzymes, and pickling, or lowering pH of the hide with salt and sulfuric acid. The pH is very acidic when the chromium is introduced to ensure that the chromium complexes are small enough to fit in between the fibers and residues of the collagen. Once the desired level of penetration of chrome into the substance is achieved,the pH of the material is raised again to facilitate the process. This step is known as "basification". In the raw state chrome tanned skins are blue and therefore referred to as "wet blue." Chrome tanning is faster than vegetable tanning (less than a day for this part of the process) and produces a stretchable leather which is excellent for use in handbags and garments.

Last edited by TheLivingShadow, 5/27/2011, 8:09 am


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gov pdf


]leather tanning pdf

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5/27/2011, 9:15 pm Link to this post Send Email to TheLivingShadow   Send PM to TheLivingShadow Blog
 
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brain tanning


checking the wikipedia page on leather, one reads about...
- Vegetable-tanned leather
- Boiled
- Chrome-tanned
- Aldehyde-tanned
- Formaldehyde tanning
- Brain tanned
- Chamois
- Synthetic-tanned
- Alum-tawed
- Rawhide
... [sigh]

What caught my attention was BRAIN TANNING; it gives good quality leather and the brain of the animal killed is simply used to tan the hide:

- take brains, add cup of water (or less), boil for 10 min.
- skin
- clean (off membranes, fats)
- work with brain blend
- wrap in wet towel and allow to set
- do it again
- stretch hide until soft
- smoke [for water-proofing and against moths]

These hides are even edible.

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10/22/2011, 7:43 pm Link to this post Send Email to TheLivingShadow   Send PM to TheLivingShadow Blog
 
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rawhide


[technically not a leather]

Wiki says:
Rawhide is made by scraping the skin thin, soaking it in lime, and then stretching it while it dries. Like alum-tawing, rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather; it's primarily found in uses such as drum heads where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching and for making many varieties of dog chews.

As lime is also easily produced and leather [rawhide] laces are an important basic tool, this is also a very good one to learn and remember.

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10/22/2011, 7:55 pm Link to this post Send Email to TheLivingShadow   Send PM to TheLivingShadow Blog
 
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pigeon !@#$


this YouTube vid they show Moroccans in Fez making leather with pigeon !@#$.

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10/22/2011, 8:05 pm Link to this post Send Email to TheLivingShadow   Send PM to TheLivingShadow Blog
 
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hide tanning the oldfashioned way


hides
24 min. YT vid by MayeuxMinisteries

for Fur and Hide Tanning 4 min. YT vid

Hide Tanning the Old Fashioned Way YouTube vid

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