Making leather will start with an animal hide and by the end of the journey there will be a piece of leather ready to be transformed into a bag, clothing or any other leather product.
How leather is made hasn’t changed much over the past several thousand years. That being said, the entire process of making leather available for manufacturing is certainly not simple. In fact, it takes an average of 10 working days to turn hides into leather.
Skilled artisans – known as tanners – are highly knowledgeable, and they perform their duties with the utmost care. The process of leather production is lengthy and complicated, which helps to explain the high retail price tag associated with leather goods.
From a salted hide to a high quality piece of leather, I will show you exactly how leather is made.
How leather is made
1. Raw material
Leather can be made from the hide of almost any animal including pigs, sheep, goats and crocodiles. However, the most common hide used is that from a cow. A by-product of the meat and dairy industries, the art of making leather uses hides that would otherwise be destroyed. Rather, by making leather, the animal’s hide is turned into a beautiful and useful material that will last for decades. Of course, the upbringing of the cow will affect the quality of the hide produced with a good hide giving an 80-90% yield.
When a hide is prepared, the skin is removed from the animal and then the flesh needs to be removed, which can be done by hand or by using a fleshing machine. If you are doing it by hand, it’s important that the process is done as quickly as possible as the material can easily dry out. At the end of the process you should be left with a white, clean surface.
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.
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. This process will also soften the hide. If you don’t want to use chemicals, the hair can be removed in a similar fashion that the flesh was removed by hand.
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. This is done so separate parts of the hide can be used for different types of leather product. The upper part of the leather split is saved for the highest quality leather products such as full grain leather. This is due to the fact the upper layer has a much tighter fibre structure making it more durable. When treated correctly this layer makes for a stunning and supple leather.
The bottom layer of the hide will be kept for cheaper leathers with less overall quality than the top layer. These tend to be used for top grain and split leathers and are most commonly used for shoes and bags.
2. Tanning
Now that the hide has been prepared, the second stage in the leather-making process is called tanning and will convert the hides into leather through preserving the material and halting decomposition.
To do this, hides need to be loaded into a special tanning drum along with a special tanning solution. This drum will contain a special mix of either vegetable tanning agents or a chromium salt mix. At the end of this process, special fats are added to the leather which will help the leather be both stronger and softer in what’s called a liquoring process.
From here the excess moisture needs to be removed – usually by applying a high pressure to the hides by passing them through rollers. After this drying process, the hides can then be inspected and arranged in levels of quality with those impaired with imperfections being of lesser quality. The grades of leather will determine what that hide will be used for in future. Hides that have been treated with chromium salts will appear pale blue.
Hides are then shaved to a specified uniform width and any shavings can be used to make bonded leather, floor tile backs, belts and recycled leather.
3. Re – tanning
A second tanning process can occur again in order to get the leather fully ready for its intended purpose. This will be a repeat using either the vegetable mix or with the chromium salts (or a combination) and the excess moisture is again removed using pressure.
Once the tanning process is complete the hides need to be dried. This drying can occur with a variety of processes such as air dried or vacuum dried. Air drying a hide involves putting a hide on something like an overhead conveyor where it will be rotated until completely dried. Vacuum drying is a quick method of drying, obtained by removing all the air from around the hide. This method will cause the hide to shrink slightly but will leave the hide with a smooth and tight texture.
During the re-tanning stage a bleaching agent can be used and this provides an excellent base to start the leather dyeing stage.
It is then packaged according to the requirements of the client and stored safely until the date of dispatch.
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