Processing Steps of Vegetable Tanned Leather - Trendiesty Worldwide

Processing Steps of Vegetable Tanned Leather

The transformation of the Hides to obtain leather on a product requires a high level of perfection for the production to be qualitative. Several complicated and complex steps follow one another and must be executed with perfection in order to achieve perfect leather

1-The conservation stage
Rawhide goes through different stages depending on the type of leather. Before reaching the tannery, the hide must be preserved and protected. In the hours following the slaughter of the animal, the decomposition of the hide must be avoided. In order to prepare the hide for the tanning process, it must be checked to ensure its quality, then the ends are cut off before soaking it in water for a period of between three and twenty-four hours. The hide is cleaned of dirt and impurities and then salted, either dry or wet, or placed in acids and salts to remain in good condition during transport and storage to the tannery.

There are a group of methods used to prevent raw hides from rotting before being transferred to tanneries, including drying. The dry scalp does not rot. It returns to its natural state after soaking in water, but the most widely used method is the ancient craft method of salting. The skins are salted on both sides and laid out in the sun and the layer of salt is vigorously applied by rubbing with the hand to facilitate penetration. The melting salt is replaced by a new layer, the operation takes three to four days.

2-The river work
The river work is the first stage of transformation that the animal skin will undergo. It modifies the nature and properties of the leather, as it makes it more resistant to natural decomposition factors. It transforms the hide into a product usable by man

The river work is carried out with an ancestral artisanal method. Today, it is done in one go in huge barrels. But in Morocco, it is still done by hand as in the Middle Ages. The objective of the river work is to obtain a rather flexible but robust leather. Thus several manual steps follow one another, executed with precision and discernment.

The first operation in the tannery consists of soaking the hide in a basin of clean water in order to get rid of impurities, namely the animal's blood and salts accumulated inside. The leather is soaked for a period varying according to the season, the needs, and the type of skin. It varies from one night in summer to seven days in winter. The objective is to restore the water that the hide has lost during salting and preservation. The skin regains its initial weight and swells slightly.

The calcination
Called in Arabic "Iferd", during this process, the raw hide is soaked in a basin containing a mixture of cow urine, quicklime, ash, water, and salt. This caustic mixture helps break down the strength of the leather, loosening excess fat and flesh, and hair that has remained on it. Placed in this basin for two to three days, the products weaken the hair strands and the inner surface of the scalp and thus prepare for the next step, which is hair removal. The skins macerate in this mixture for 15 to 20 days in summer and up to 30 days in winter.

Hair removal
Next, the tanners remove the excess hair and fat by hand to prepare the hides for the tanning stage. Using a knife held in both hands, they pluck the hair from the fleece stretched on a pole leaning against the wall. This dehairing work is done in special rooms, arranged around the central area. As this operation continues, he removes and slides up the part of the skin that has already been removed, which hangs between the wall and the pole.

The dehaired skins are then plunged into lime basins filled with water, which is then mixed with slaked lime and quicklime. The master tanner must keep a close eye on the duration of these baths. Often, especially in the summer, it will be necessary to get up at night to remove the skin for depilation.

When the leather is soaked in pure water to ensure the removal of calcium, the leather is soaked in an acidic medium to make the acidity of the hide suitable for the subsequent tanning processes. Typically, the basins contain a mixture of water and pigeon droppings. The pigeon droppings contain ammonia, which acts as a softening agent that makes the leather malleable so that it can better absorb the dye. The tanner uses his bare feet to knead the hides for up to three hours to obtain the desired softness.

The washing
The hides that have become perfectly clean go through the washing process. The tanners spread the hides in water basins to be gradually purged of lime. They first undergo a preparatory washing of two hours in the first basin and then they are thrown into a second deeper basin where a team of two or three workers goes down to tread them methodically, giving rhythm to their efforts with a characteristic melody. They are bent over and leaning with both arms on the edge of the basin. They plunge their feet in cadence in the skins which they tread and piaffe like impatient steeds. The skins evacuate their impurities and the traces of lime that they kept, the whole flow with the water and is constantly renewed. This operation lasts about three hours.

3-Leather tanning
The hides are beaten with alum stone, oil, and water before receiving the dye. This operation is performed by the tanners themselves on the terraces. The hides are placed in dye pits containing natural vegetable dyes.
Vegetable tanning: this is the oldest method of tanning, it depends on the parts of the plants for the presence of tannin, i.e. tannic acid in them, which produces strong and water-resistant hides.

4-Softening of the leather
The hide is stretched lengthwise and the worker works bent over constantly, pressing the wooden bow against his chest. With his right hand, he holds the iron handle, while the left hand is used to stretch the hide. The smoothing is done on the flesh side and then the graining is done on the flower side on a small terracotta dome.

Once the leather is dyed, it is put to dry in the sun. The finished leather is tanned and softened, and then processed and used to make our leather goods including handbags, wallets, belts and boots. Many of these products are being manufactured in our manufactories in Marrakech and Hong Kong before making their way into European and American markets.

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