Preparatory Processes Before Tanning

leather_preppingAll the tanning processes go through these basic processes. They are important because they enhance and improve the transformation of skins and hides into leather. The preparatory processes include slaughtering of the animal, soaking, fleshing/ defleshing, dehairing, bating and pickling.

1. Slaughtering of the animal:
The leather preparation process begins with the killing or slaughtering of the animal. The skins or hides of the animal is peeled off or removed. This process is termed as Flaying. The pelt is hanged for the liquid in it to drain off. It is then dissolved in heavy salt or brine solution. This process is referred to as Curing. It is done to prevent the skins and hides from bacteria and other insect attack or decay.

2. Soaking:
The pelts are soaked in paddle vats filled with water added with chemical wetting agents. This helps in restoring some of the natural moisture lost during the curing process. It also makes the pelts soft and improves its aesthetic appeal whilst disinfecting it from further insect and bacteria attack.

3. Fleshing/ De-fleshing:
This is the removal of the excess flesh, fat and muscle found on the fleshy side of the pelts. A special fleshing machine equipped with cutting blades and rollers scrapes away the flesh from the inner side of the leather.

4. De-hairing:
This is the removal of hairs from the surface of the leather from the grain side. This is done by both chemical and mechanical means. Depilatory chemical agents like lime solution destroy the hairs by attacking the hair roots. It also loosens the epidermis and removes certain soluble skin proteins that lie deeply embedded within the skins and hides. Finally, they are subjected to the de-hairing machine that removes all the hair through a mechanical rubbing procedure.

5. Bating:
This is the process of removing all residues including those of the chemical agents used in the de-hairing process as well as the hair particles deeply entrenched in the surface of the skins and hides. Three processes are involved in the bating process. The skins and hides are first washed in a lime solution. Secondly, they are soaked in a bate solution (bate is similar to enzymes found in the digestive systems of animals). Thirdly, they are then finally re-washed thoroughly to remove all substances on the leather.

6. Pickling:
This is the final preparatory stage before tanning. It conditions the leather to receive and absorb the actual tanning agents. The skins and hides are submerged in a solution of Sulfuric acid mixed with common salt. This process helps in preserving the skins and hides, keeping them chemically balanced while preventing them from swelling.

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Reasons for Decorating and Finishing Leather Items

Decoration is the means or process through which the appearance of an artwork is enhanced or made more attractive. The decoration of articles and works in leatherwork has several benefits or importance both to producers, customers and the product itself. Finishing is the treatment given to products to change, improve or develop their appearance or behavioral characteristics. This treatment improves the hand and makes the products very attractive. It is the final methods and processes of preparing the leather for use, of polishing, buffing or otherwise after the completion of the leather artifact. Some of the reasons for decorating and finishing leather products are discussed in this article.

1. To enhance the value of the leather products- Decorating leather items aid in increasing their aesthetic appeal and makes them more attractive.

2. To attract high price- Decoration of leather helps in adding market value to the product. It raises its price and worth. This makes the leather craftsman earn a lot of income.

3. To meet standards for export- Well decorated products helps such works to meet exportation standards. They can be exported to other countries to earn foreign exchange.

4. To show respect for the customer- Well decorated items in leather makes the client feel respected and honored when he comes to the shop to purchase the item. While poorly decorated leather items ridicules or demeans its buyers, well decorated leather items boosts their respect.

5. It helps the leather craftsman to have a sustained market- A leather craftsman whose leather crafts are well decorated continues to enjoy a prolonged market. Also, the leather craftsman gets a large pool of clients to work with due to his well decorated leather items.

There are several reasons for finishing products in leather. Some of these reasons are outlined below.

1. To make the works durable or permanent- When leather works are finished properly, it makes them stand the test of time and prolongs the duration for their usage.

2. To protect works against weather, wear and tear- Finished leather products are well protected against the harsh weather condition as well as wearing out and tearing. It helps the works to be resistant to harmful external attack such as water spillage etc.

3. To act as a means of restoring leather-Designed products in leather that are well finished have an improved usable and functioning condition. That is, they have good workability and perform better than unfinished leather items.

4. To prevent mold from growing on leather items- Finished leather pieces resist strongly, the growth of mold, mildew, decaying and fungi attack.

5. To make them attractive- Leather products that are well finished attract customers and clients. The purchase rate or markets of such products are usually very high.

6. To add value- Finished leather products have an added value on them. This includes an added pricing, attraction and market value to the product.

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Tanning After-Treatment Processes

There are some treatments that are given to leather after they have been tanned. Some of these include washing, setting out, oiling, stuffing, and drying.

It is also referred to as scouring. This is done to remove any surplus tan from heavy leathers and chrome salts from light leathers.

Setting Out
This is done to stretch the leather to remove any wrinkles and flatten heavy leather. It is also done to remove creases and surplus moisture in light leather. After this process, the pelts still contain about 60% moisture.

This is the application of oil to the grain side of the leather for it to be flexible and be of good colour. It is done to replace the oil lost during earlier treatments.

This is the process of impregnating the leather with oil and fat to make it waterproof or suitable for mechanical leathers or make it more resistant to wear.

This is done by pasting the hide onto a glass plate or metal sheet or by toggling that is pinning the leather onto a large wooden sheet with holes in it. This is done to compress the leather and make it firm and flat. Another process of drying it is to paste the pelts on large plates. It is then scrubbed, wiped and dried either with the solar energy or in a drying oven. The drying process also helps to remove the remaining moisture or water and smooths the grain. Again, it helps in avoiding hardening or shrinkage of the leather.

This is the process of re-wetting the pelt with a fine spray mist of water to raise the moisture content to about 25%. The drying process makes the pelt too hard and unworkable for most consumer use. Therefore, this is done to re-establish the pelt to its proper moisture content.

This is the process of mechanically softening the pelt by both pulling and rolling to make it pliable. It gives the leather its final firmness and softness.

This is a mechanical sanding process that reduces the visual appearance of surface blemishes on the grain side of the leather. A full grain leather is not buffed.

This is the process of applying a thin finish film on the grain side of the leather to enhance the colour and increase the pelt’s resistance to stain and abrasion.

This process smoothes the finish grain surface and assists in fixing the finishing film on the leather.

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Importance of Paper Designing in Leatherwork

Designing is an important step that ensures the success of any article.The truth is that the leather material for the production of items are costly and as such, a leather craftsman cannot just experiment with it, thus, paper is used to test the feasibility of a particular design before it comes to life using leather. Detailed merits of paper designing prior to actual three-dimensional production in leather sounds professional and advantageous for many reasons,some of which have been dealt with in this article.

1. It helps us to generate various unique and original designs from which articles can be produced- Designing takes several phases or stages in their development which some designers’ term as idea development. This systematic development ensures that original designs which are not already in existence are created.

2. It helps designers in incorporating client’s preferences into the design of the article- When articles are carefully planned and designed, it gives designers the opportunity to include the taste of customers with respect to colour, shape, form, etc. in the design. This deepens the trust that clients have in the leather craftsman, paving the way for commissioned future projects.

3. It helps designers to visualize the final outlook of the product- Designing of products before they are actually produced help designers to first preview how the product to be produced will look like. Thus, when shown to clients saves designers from unpleasant surprises from clients.

4. It helps us to make corrections before the preparation of templates and the cutting of leather- If designs are first generated before actual production, corrections can be conveniently made before it’s too late. When designs are made and shown to clients before actual production, the changes the client wants the designer to make can be easily carried out.

5. It saves time and resources- All the toils and difficulties that result in the production of articles is mainly due to the failure of leather craftsmen in taking ample time to plan and design the article. However, all the efforts in designing is time worthier. This is largely true because the time and resources that would be wasted if a mistake is committed would be far greater than the time that was spent in designing.

Owing to the enormous advantages of designing products before their actual production, the author of this book is advocating that a product in leatherwork must not be produced if the paper work (design) is not carefully and properly carried out.

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