How is Leather Made? the Manufacturing Process of Leather

Everyone has some leather products in the house, like leather jackets and leather shoes. But how is leather made? This blog will tell you five steps to produce leather.

Making leather is a time-consuming, technical process that requires accuracy and cares to produce high-quality leather with the same finish every time.

So, how is leather made? The leather manufacturing process is a series of five phases that begins with raw material preparation and ends with final inspection and shipment:

1. Raw Material
2. Tanning
3. Re-Tanning
4. Dyeing
5. Finishing

The specifics of each part are provided below.

Raw Material

Leather can be made from the hide of almost any animal including pigs, sheep, goats, and crocodiles.

However, the hide from a cow is the one that is most frequently used. The process of making leather uses hides that would otherwise be wasted and is a byproduct of the meat and dairy industries. Instead, the animal’s hide is transformed into leather, a stunning and practical material that has a long lifespan.

Of course, the upbringing of the cow will affect the quality of the hide produced with a good hide giving an 80-90% yield. Cows with branding, those who have received numerous insect bites, those who are kept close to barbed wire fences, and those who have had electric cattle prods used on them, for example, may have damage to their hide.

Here you’ll find that the hide yield is more likely to be around 60% so as to avoid blemishes and holes. Even some diets that contain grains or growth hormones can lead to lower-quality hides.

When preparing a hide, the skin of the animal must first be removed, and the flesh must then be removed. This can be done manually or with the aid of a fleshing machine.

The process must be completed as quickly as possible if it is being done by hand because the material is prone to drying out. You should be left with a white, spotless surface at the conclusion of the procedure.

At this point, a hide should be salted or placed in a salt brine. This needs to be a very generous layer of salt as the salt is what stops it from decomposing. Within a few hours of being removed, a hide can start to decompose and risk becoming useless and wasted if it is not salted, brined, or frozen.

The hides are typically folded with the flesh sides touching, stored, and salted. When the hides are ready for processing, they should be soaked in water to remove any debris or other materials.

If a hide has hair on it then it will need this removed, which is executed using a chemical solution that contains calcium oxide. This may be called a lime bath too and the soaking can take one to two days.

The process will also make the hide softer. The removal of the hair can be done in a similar way to how the flesh was done if you don’t want to use chemicals.

After all this bathing and soaking, the hide will be full of moisture so it will swell to be around 4mm thick and can be spliced into two layers. The purpose of this is to allow different types of leather products to be made from different portions of the hide.

For the best leather goods, such as full-grain leather, the upper portion of the split leather is reserved. The upper layer’s much tighter fiber structure, which makes it more durable, is the reason for this. When properly cared for, this layer yields gorgeous, supple leather.

For less expensive leathers with a lower overall quality than the top layer, the bottom layer of the hide will be retained. These are typically used for top grain and split leathers and are most frequently used for shoes and bags.

Tanning

The pelts are turned into leather during the tanning process, which stabilizes the protein structure of the hides and skins to make them tough, chemically resistant, and less prone to decomposition. In the past, chrome, vegetable tannins, and chrome-free alternatives have been the main tanning ingredients.

After tanning, hides are typically split if they weren’t split during the beam house operation.

Following tanning, leather that has been treated with chrome is referred to as “wet-blue,” leather that has been treated without chrome is referred to as “wet-white,” and leather that has been treated with vegetable tannins is referred to as “vegetable or veg-leather.”

Re-tanning

The leather is then finished being re-tanned in order to alter its physical properties to match its intended use. Chromium salts, plant material, or a combination of the two are used to re-tan leather, giving it a distinctive hand or texture.

The extra moisture is then removed from the hides by running them through a sammying machine once more. The hides are once more sorted and put away.

The next step is drying the hides in a vacuum, an oven, or the air. When using vacuum drying, hides are positioned on a flat, temperature-controlled surface, and a top is lowered to create a vacuum over them.

This vacuum makes it possible to quickly extract the water, which results in a tight, smooth grain texture. Vacuum-drying leather causes it to shrink by about 5%. If the air-drying technique is employed, hides are hung on an overhead conveyor that moves around the tannery until they are completely dry.

The hides are massaged mechanically during the staking process, making them supple and soft. Hides are draped over horses after staking and after hides are dried, they create a “crust.” The bleaching agent used in re-tannage provides a good base from which to start dyeing and enables excellent clarity and color uniformity.

Dyeing

The gorgeous color of a finished leather design is added during the leather dyeing process. The colors used for this can range from bright, bold hues to dark, leather-like hues of brown and black. Without the careful formulation of each dye using a highly accurate computer program, it would be impossible to achieve a constant color every time.

The actual dyeing procedure can take a very long time because hides must be added to a big drum with their chosen dye and left there for a long time to ensure the dye takes. A cutting should be made after about 8 hours to make sure the dye has completely saturated the hide.

Otherwise, the leather will appear scuffed. To get rid of any remaining dye or chemicals, the leather must then be thoroughly rinsed. The hide should be fully dried after rinsing.

Finishing

The hide may now be finished, allowing for the eventual removal of the skin’s remaining oils. Additionally, leather is modified with additions like oil addition to increasing flexibility, which is used for a variety of leather products.

At this point, the leather is also dyed. Now that the leathers have undergone all necessary processing, they can be used to make a variety of clothing items, shoes, or other things.

Conclusion: How is Leather Made?

The transformation of what is essentially a by-product of meat consumption into a usable and desirable luxury material that is used for bags, belts, and a variety of other everyday wares involves five steps.

Although the process of creating leather appears to be difficult, it is actually long and results in a variety of high-quality materials that we use every day.

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