Guys
Contenido
Los diferentes tipos de cuero se clasifican según varios criterios: la procedencia de la piel, la estructura y capa de la piel utilizada, el método de curtido y el acabado superficial aplicado. Cada uno de estos factores influye en las propiedades finales del material, como su resistencia, textura, durabilidad y apariencia.
According to its origin
The hides have different types depending on the origin of the skins, and differ in their structure depending on the life habits of the original animal, the age "Development (biology)") of the animal, the sex, and the season of the year in which it was treated. The first category could be:
• - Cattle.
• - Goats.
• - Pig.
• - Equines.
• - Otter.
• - Chinchilla "Chinchilla (animal)").
• - Reptiles.
• - Fish Shark skin is sometimes used.
• - Cervids such as deer, fallow deer or reindeer.
Likewise, there are various synthetic materials with characteristics similar to leather. They are generically known as synthetic leather or imitation leather, and are usually made with different types of plastics.
Depending on surface finish
• - Suede or suede: Type of finish in which the surface comes from the fleshy side or from a split sheet of the dermis and is subjected to plushing or polishing that generates a short and uniform pile with a velvety sensation. Suede is more flexible and less resistant to wear than intact grain; requires specific care due to its greater sensitivity to water and stains.[29][30][31].
• - Nubuk"): Finish obtained from the external face of the grain that has been lightly sanded or burnished on its surface to produce a short, fine hair similar to that of suede but coming from the natural grain. Because it comes from the grain side, nubuck combines a velvety texture with greater mechanical consistency than suede, although it retains the sensitivity to stains and humidity typical of velvety finishes.[32].
• - Roughout leather: Presentation in which the piece is manufactured with the fleshy side or with the plush side of the chorion facing outward; In some processes, a complete piece of flower is used, turned upside down, to expose the inner face as the outer surface. Roughout exhibits a rough and more adherent texture, and in footwear and saddlery applications it is valued for its resistance to scratches and its behavior under rough use conditions; Waxes or other treatments are frequently applied to improve waterproofing and chromatic stability.[33][34].
• - Polished leather: A set of finishes in which oils, waxes or special fillers are applied to the leather during or after tanning to obtain a surface that has a controlled shine, greater water repellency and a characteristic chromatic response to bending or stretching. This treatment produces leathers classically used in heavy-duty boots and cowboy boots for their feel, ability to develop patina, and functional robustness.[35].
Tanning process
The first step is to cut off the excess limbs and soak the fur in water for a period that can last from 8 hours to two days, depending on the size and condition of the skin.
Vegetable or mineral methods are then used to stabilize the collagen in the skin and transform it into leather.
• - Vegetable tanning uses tannins that are produced naturally through the bark of trees. The skins are completely stretched and placed in vats containing concentrations of tannin.
• - Mineral tanning is a modern technique that emerged during the century in which the use of chromium, a white metal, predominates. It is a faster process than the previous one that results in a more resistant and durable leather than that of vegetable tanning.
The next step is to carry out mechanical drainage to remove excess moisture. Subsequently, the skin is scraped to give a homogeneous thickness to the leather.
On many occasions, a "retannage" is used, that is, the leather already tanned in a mineral way goes through a process with the use of tannins (vegetable) with the aim of giving a softer and more natural appearance to this fabric.
Refining and finishing
The last step is to dry the new piece and refine it by using oils that give the leather its characteristic texture.
Once this long and complex process is completed, the leather can now be molded and used to create wallets, bags, jackets, pants or any other item desired.
• - Cooked leather: Leather hardened by introducing it into boiling water, wax or fat. By this procedure the collagen fibers are shortened, and the piece of leather shrinks and becomes rigid and much harder. If only water is used, the result is brittle, but if wax or grease is used, it soaks the piece and the result is much more resistant. In the few minutes that the piece cools, it becomes very moldable, later maintaining the shape obtained once it hardens. Not all tanned leather is suitable for this practice; vegetable-tanned leather is usually used.
Historically this procedure was used to make leather armor, but it has also been used for book binding or the manufacture of small furniture or chests. It is currently used in crafts, recreation, live role playing and even for sculpture.
• - Oiled leather: Oiled leather to increase its water resistance. This replenishes the natural oils that remain in the leather after the tanning process, which are lost with continued use. All tanned leather can receive grease treatment, although leather tanned with natural products, being more porous, absorbs grease better. Frequent oiling keeps the leather flexible, prevents it from becoming brittle and significantly extends its good conservation.
• - Dyed leather: Leather treated with dyes to achieve decorative tones. All types of tanning can be dyed. To dye leather in crafts, aniline dyes dissolved in alcohol are used, applied with cotton or fabric, or acrylic paints usually applied with a brush. The former provide translucent colors, similar to those obtained when painting on cardboard with watercolor, and it is necessary to paint everything at once, since from one time to the next the alcohol will have evaporated and the resulting color will have changed tone. Acrylics, on the other hand, provide a uniform color. In leather for industrial use, all types of paints and solvents are used, depending on the type of leather to be obtained as a final result, usually applied by immersion procedures.
• - Patent leather: Leather covered with one or several layers of polyurethane varnish that gives it a characteristic shine. This treatment waterproofs the leather and makes it more resistant.