A little over one-hundred years ago, most people over the age of ten had an intimate understanding of where the meat on their table came from, and how to honor those fallen animals by using each and every part of them for survival. This knowledge included in-depth knowledge of how to turn animal skins into leather which can be used to make everything from hats, shirts, coats, pants, boots/shoes, saddles, collars, leashes, and so much more.
Much of the leather-making knowledge that existed years ago is no longer passed from parents to their children, as you can readily buy leather online or from a local retailer at affordable prices.
Modern processes to make leather haven’t really changed much from traditional means, other than the advent of machines and the use of industrial chemicals to seal and preserve the finished product.
If you’re curious how leather is actually made, from start to finish, keep reading.
Post Hide Removal
Immediately after removing the hide from the animal, salt (usually common marine salt) is put on the hide immediately to dry it out and protect it from the decomposition process during its transport to the tanning facility.
Another less common method is to slow cool the hide in a refrigerator. This process is called “defrosting.” This method is never used by Italian leather manufacturers and in general, isn’t the preferred preservation method used by most.
When done properly, either method works just fine and won’t affect the end product. However, salting is the fastest and most economical method to preserve the hides while they’re being transported to the tanning facility.
Preparing Leather for Tanning Process
There are a few rather time-consuming and laborious processes that go into preparing leather for the tanning process, which converts the hide from organic matter that’s prone to decay, into the fine products leather consumers have come to love throughout the ages.
-
Water Soaking (Re-hydration): After the hide has arrived at the tanning facility, it’s soaked in a cold water bath for several hours and up to several days, in order to hydrate the dried skin and attached fatty materials.
-
Fleshing and Unhairing: The subcutaneous fat and hair are removed from the hide using a bladed machine, sometimes by hand.
-
Liming: Lime is applied to the hair and virtually fat free hide. This swells and expands the hide, allowing the tanning chemicals that will be used later to seep into the skin more easily. Liming also enables manufacturers to split thicker hides, such as those found on cows, into two separate layers for use in products that require intricate shaping.
-
Deliming and Bating: A variety of chemicals are used to eliminate the swelling caused by the liming process, and restore pH balance to the skin to prepare it for the next stage. Bating smooths the grain of the hide and loosens up the fibers to make them flexible.
-
Degreasing: Removes fatty acids and other organic materials from the hide to ensure the finished product doesn’t degrade prematurely.
-
First Tanning: This process converts the remaining proteins in the skin to a stable material that won’t rot or degrade. Chromium salts or vegetable tannins (also called “Tree Tanning”) are the most common agents used to stabilize any remaining biological material on the skin, and often finished with glutaraldehyde, which is a disinfectant/preservative.
At this point in time, this raw material is no longer considered an unpreserved hide, but isn’t quite ready to be transformed into a finished leather product either.
Intermediaries who specialize in prepping leather will normally sell to manufacturers who make leather products at this point, though some garment manufacturers complete the entire process from start to finish themselves.
Retanning
As mentioned, at this point in the process the raw material that will be later used to make leather products isn’t quite ready to be made into your favorite coats, shoes, belts, etc. The tanned leather isn’t quite dry yet and if allowed to do so, would become inflexible and brittle.
A variety of chemicals will be introduced to the leather at this stage, and additional finishing processes completed, to make the finished leather product supple to the touch, and visually appealing, both so the grain stands out and the desired coloring can be applied.
-
Drying and Shaving: The tanned leather is moved between two rollers to squeeze most of the remaining moisture out, then shaved using a machine to completely smooth out the leather and remove any remaining material left over from the fleshing process.
-
Re-tanning and Dyeing: Chromium and other tanning agents that are largely proprietary to the manufacturer are added to soften the leather after the drying process. Dye is added at this stage to achieve the desired color for the leather.
-
Fatliquoring: Fatliquors; small quantities of fats and oils, are added to the leather to maximize fullness and flexibility of the leather. Animal brains were the preferred source of fatty oils before modern manufacturing made brain tanning largely obsolete.
Finishing the Leather
At this stage, the almost-ready leather is prepared to be converted into the desired end product. There are just a couple of key steps to go before it’s made into a fine leather belt, pair of shoes, or other clothing item.
Drying:
The leather is exposed to air, either in an open space, or vacuum chamber until it’s completely dry.
Polishing:
This is the final stage before the leather is made into a finished product. There are a variety of methods used, depending on what the leather will be used for, and the desired look and feel the manufacturer wishes to achieve:
-
Velvet Rubbing: A velvet wheel is rubbed over the leather using a machine, to make leather with a smooth surface.
-
Ironing: Ironing creates a smooth but also very flat surface on the leather.
-
Embossing: As the name would suggest, embossing processes are used to emboss 3D prints into the leather.
-
Tumbling: The leather is place in a drum that’s rotated quickly to make the grain more evident in the leather.
-
Chemical: A variety of chemicals, often proprietary, are added into the leather, using a variety of methods to achieve the desired end look and feel the manufacturer needs.
After polishing, the leather enters the final stage, where it’s cut, shaped, and molded into any number of fine leather products.
After learning all the processes involved, it’s not hard to justify the higher price tag placed on genuine leather, when compared to less expensive synthetic products made from PVC and polyurethane.
Finally, it’s worth noting that if animal hides weren’t made into the leather so many of us have come to love dearly, it would essentially become waste. Many of the most popular leather products are made from commercial animals like cows, sheep, and goats. Animals that are farmed and killed to provide food and sustenance.
Reputable leather manufacturers attempt to only source their leather from ethically treated animals, who are raised firstly for their meat and dairy, and second for the hides they provide for making leather.
