The care of your leather is not just about making it look nice it is about extending the life of your leather goods and sustaining the look for the long term.
Regardless of how much you spent on your leather product, conditioning and protection from dust, dirt, snow, rain and even sun always makes sense.
Keeping your leather product in wonderful condition will eliminate the need to buy replacements as often, so you'll be saving money just by investing a small amount of time and effort. Leather can be virtually indestructible if treated properly. With a little bit of care and attention, your new leather will last well into vintage age and your leather will continue to have a long happy life.
The most important things to remember about leather is not to get it soiled, soaked, or let it dry out. Despite the fact that all of these things can be rectified to some extent, it is helpful to not let leather get into such a condition in the first place. Proper storage, cleaning, and conditioning will keep leather looking as good as new no matter how old it is.
Although leather is very durable, it is not indestructible. Improper care or cleaning can crack and dry leather skin, removes finishes and colors, or makes it too stiff to wear. Keeping leather away from chemicals, heat, and humidity are key. If leather is like skin, think of its care as anti-aging; if you wouldn't put it on your own skin, it probably isn't very good for the leather either.
There are various types and grades of leathers, each serving a different purpose. Some require a bit more maintenance than others, but all follow a set guideline of care to ensure a longer life.
There are four stages in leather care that include cleaning, conditioning, polishing, and protection. When examine the store shelves for a product that fits your needs, be watchful for what kind of product you're purchasing. It can be confusing to try and figure out which product is for which stage, but look for words that explain how the product is to be used. It is also important to remember to work on your leather in a well-ventilated area. Some leather care products are very strong and can cause irritations.
Cleaning
To clean a leather item, first choose a cleaner that will help preserve the natural lubricating oils instead of stripping them. For example, saddle soap is a commonly used product for equestrian tack. It is meant to be used as a cleaner and a protector from moisture, but it strips the leather of the oils in the process of attempting to do two jobs at once. The cleaner of your choice should not leave any greasy residue behind. Residue makes leather susceptible to bacteria and can break down the stitching of your item. Before applying anything to your leather item, be certain to test it out for effect and possible color distortion on an area that isn't visible to the eye. Once you've ascertained whether the leather care product is acceptable to use, apply it to your item. With a slightly dampened cloth, remove the cleaning product. For areas with stitches, there are brushes available on the market. Another cleaning product to consider having in your leather care collection is a nubuck cleaning cloth. They have an astonishing ability to clean and restore leather to its original look.
Conditioning
Leather conditioners are meant for occasional use. They contain fats and/or oils that help lubricate leather and replenish the suppleness. Look for a product that will penetrate the strong fibers in leather, but beware of any that include petroleum or mineral oils. While petroleum by-products won't damage your leather immediately, they do over a period of time. Again, just as with cleaning, keep on the look out for thick, greasy conditioning treatments for the best care of your leather.
Polishing
Polishing is done for special occasions when you want a more glossy finish on your leather. There are a couple things to be wary of when purchasing a polishing agent. Some products contain coloring factors that will brush off on things you come in contact with. Some products also have a tendency to clog the pores in leather or dry leather out. Just as with cleaning, be sure to test out the product on a small area and when ready, buff to a shine.
Protection
Moisture barriers are extremely vital in preventing rain or other liquid hazards from damaging leather. Stiffness and spouting will happen if leather isn't protected beforehand. There is a drawback in protecting leather with a moisture barrier product. They tend to fill in the pores with a greasiness that makes cleaning, conditioning, and polishing difficult, but it's a necessary process to ensure leather isn't destroyed. Periodically apply a moisture barrier and allow it time to penetrate and dry before using your leather item.
Remember to follow the instructions on the leather care products label that you buy. Prepare your articles, not just spray or put on anything that is not recommended for your leather product. Proper cleaning and conditioning is essential for years of lasting beauty for your leather.
Wednesday, July 1, 2009
Identifications for different Leather
Leather is the dried, toughened, tanned and dyed skin or hide of an animal. Usually available with the hair removed form. These animal skins and hides treated to preserve and make them suitable for use as much as long. By the process of tanning these skins are converts into a stable and non decaying material.
Uses and Benefits of Leather:
Leather is use to prepare leather apparel and leather garments like leather Jackets, leather coats, leather lingerie, leather pants and Leather undergarments. Leather shoes are also commonly used all over the world. Leather backpack, leather briefcase, leather bags and leather purses also have very important significance in our daily life
In its broadest sense, leather is any type of tanned animal hide. Different types of leather are characterized by both the type of animal skin used and the tanning and manufacturing methods employed. The most common types of leather are made from cow hide, but leather from other animals, such as kangaroos and ostriches, is also popular in certain applications. Different types of leather are suited to different purposes, including clothing, footwear, luggage, book binding, and drums.
A variety of animal skins are used to produce different looks in leather. Once leather is tanned and processed, certain sections are selected for use on a particular application. It will then go through another series of processing and splitting for each application. Leather quality is determined by the actual processes and chemicals used in its production. Respectable manufacturers use high quality in the production of furniture, car upholstery, as well as jackets and clothing. Lower priced leather on the other hand, means lower quality and is less durable in the long run.
An animal hide can be made into leather by a number of different methods, each of which lends different properties to the final product. Leather tanned with vegetable-based products is supple but can be damaged by exposure to water. Alum-tanned leather, created with aluminum salts, is less supple and can rot in water, but it can be made in much lighter shades than vegetable-tanned leather. A newer method of tanning, using chromium salts, results in a very supple leather that holds up relatively well in water. Brain-tanned leather or buckskin, made with animal brains or other emulsified oils, is washable and significantly softer than any of the above varieties, but it is also the rarest, as it is costly and time-consuming to produce.
Stiffer, more durable types of leather, suitable for use in drums, book binding, and, historically, armor, are created with different methods. Rawhide is made by scraping animal hide, treating it with lime, and stretching it throughout the drying process. Boiling in water or wax is another method used to make extremely tough types of leather.
The softer types of leather can be prepared in a few different ways. Full-grain leather, used in the finest leather products, is not altered past removing the hair and tanning the hide. Therefore, it requires raw materials of excellent quality. Top-grain leather is sanded on one side and given an artificial grain in order to hide imperfections in the raw material. The other side of this type of leather is fuzzy. Suede is fuzzy on both sides, as it is cut from the inside of an animal hide.
Other types of leather include patent leather, which has a very shiny, smooth finish, often coated with plastic; and shagreen, rough leather usually colored green. Many special types of leather are used in luxury products from gloves to pocketbooks. Belting leather is heavy and durable and can retain its shape exceptionally well. Napa leather is known for its softness, as is slunk, made from the hide of a calf fetus. Vachetta leather is typically used as a trim on handbags.
How to identify Leather defects ?
Leather is an incredibly wonderful natural fabric that's been used for thousands of years. No man made material has been able to surpass the natural beauty and toughness of leather but there are defects which may be caused during the life or after death of an animal.
Imperfections in the grain surface or structure of a hide or skin resulting in unsightly appearance and/ or weakness of the resultant leather. Such defects may have arisen during the life of the animal, or may have developed in the flaying and/or preparation of the stock. Defects exist on natural leather surfaces and they usually cannot be eliminated during processing. No international criterion specifies the compensatory counting for calf leather surface defects. So complicated negotiation causes additional cost and argument between suppliers and purchasers
Defects caused to hides during the life of an animal
Defects caused during life include:
1) Scars, resulting from scratches or cuts. (When the cut is healing, the fibers grow densely packed together, and the healed skin is often hard, raised, and lacking hair follicles. Scar damage is also caused by branding the animal for ownership purposes, usually in the butt area, which is the best part of the hide)
2) Infestations, such as ticks, warble flies, and mange. (Ticks pierce the skin to suck blood, leaving holes that look either like pin pricks or minor scars in the grain of the leather. This defect occurs mainly in the belly areas of the skin. Sarcoptic mange mites enter the epidermis and tunnel around, causing the cells to multiply and the hair to fall out. The grain surface becomes roughened, and the animal generally compounds the damage by rubbing to relieve the itching. In demodectic, or follicular, mange, the mites penetrate into the dermis itself, where a wall of fibers is formed to surround and "encyst" them. The cysts generally are seen on the grain of unhaired skins as small swollen nodules. Tanning and drying processes shrink the contents of the cysts, causing the grain surface to sink over the cavity so that the defects are seen as shallow depressions, though the grain surface itself is not generally damaged;
3) Infections. (If ringworm, which is a fungus, heals it leaves no scars, but if the animal is slaughtered while still infected, the grain appears coarse at the site of the infection);
4) cockle, which occurs in wooled sheep immediately before shearing. (This defect appears as boil-like hard spots, of varying size, which occur in rows at right angles to the spine from the shoulder to the butt, and, while the defect disappears rapidly after shearing, it cannot be eliminated during manufacture of the leather.)
Defects caused after the death of an animal
Damages caused after death include:
1) flay cuts and gouges, which cut into the fibers of the dermis. (In thin leathers they show through and thereby spoil the grain. Some flay cuts go completely through the hide or skin, ruining it completely. These kinds of cuts are usually the result of careless or improper flaying);
2) putrefaction, which is the result of bacterial growth which starts almost immediately once the animal is dead, unless the skin is properly cured, especially on the exposed flesh side. : PUTREFACTIVE DAMAGE;
3) vainness, in which branching lines of blood vessels can be seen on the flesh side. (If, because of poor curing or old age, for example, the structure around them becomes loose, the skin is said to be veiny, and the branching pattern of the veins usually shows through on the grain side. Veininess can actually at times be attractive in some skins, such as VELLUM.
4) damage from heat, which may occur on hides and skins in tropical areas. (It is a common fault with ground-dried skins. Sun Damage that occurs to a hide or skin when it becomes heated above a certain critical temperature while it is still moist and is laid out in the sun to dry (cure). A completely dry skin can become very hot and still not be affected under normal conditions of cure, but prior to this a skin is very susceptible to damage. Also, the drying of a salted skin proceeds so uniformly throughout its entire thickness that the cooling effect produced by evaporation off its surfaces maintains the temperature of the entire skin below the danger point until it is uniformly dry. Without salt, however, a skin tends to dry unevenly when laid out in the usual manner, which is flesh side up. This can happen because the flesh side can dry out completely and begin generating heat, while the underside remains moist, and, being shielded from evaporation, also begins to generate heat. This is especially the case when pieces of flesh, generally of a fatty nature, are present on the flesh side, and further retard the drying of areas beneath them.
Imperfections in the grain surface or structure of a hide or skin resulting in unsightly appearance and/ or weakness of the resultant leather. Such defects may have arisen during the life of the animal, or may have developed in the flaying and/or preparation of the stock. Defects exist on natural leather surfaces and they usually cannot be eliminated during processing. No international criterion specifies the compensatory counting for calf leather surface defects. So complicated negotiation causes additional cost and argument between suppliers and purchasers
Defects caused to hides during the life of an animal
Defects caused during life include:
1) Scars, resulting from scratches or cuts. (When the cut is healing, the fibers grow densely packed together, and the healed skin is often hard, raised, and lacking hair follicles. Scar damage is also caused by branding the animal for ownership purposes, usually in the butt area, which is the best part of the hide)
2) Infestations, such as ticks, warble flies, and mange. (Ticks pierce the skin to suck blood, leaving holes that look either like pin pricks or minor scars in the grain of the leather. This defect occurs mainly in the belly areas of the skin. Sarcoptic mange mites enter the epidermis and tunnel around, causing the cells to multiply and the hair to fall out. The grain surface becomes roughened, and the animal generally compounds the damage by rubbing to relieve the itching. In demodectic, or follicular, mange, the mites penetrate into the dermis itself, where a wall of fibers is formed to surround and "encyst" them. The cysts generally are seen on the grain of unhaired skins as small swollen nodules. Tanning and drying processes shrink the contents of the cysts, causing the grain surface to sink over the cavity so that the defects are seen as shallow depressions, though the grain surface itself is not generally damaged;
3) Infections. (If ringworm, which is a fungus, heals it leaves no scars, but if the animal is slaughtered while still infected, the grain appears coarse at the site of the infection);
4) cockle, which occurs in wooled sheep immediately before shearing. (This defect appears as boil-like hard spots, of varying size, which occur in rows at right angles to the spine from the shoulder to the butt, and, while the defect disappears rapidly after shearing, it cannot be eliminated during manufacture of the leather.)
Defects caused after the death of an animal
Damages caused after death include:
1) flay cuts and gouges, which cut into the fibers of the dermis. (In thin leathers they show through and thereby spoil the grain. Some flay cuts go completely through the hide or skin, ruining it completely. These kinds of cuts are usually the result of careless or improper flaying);
2) putrefaction, which is the result of bacterial growth which starts almost immediately once the animal is dead, unless the skin is properly cured, especially on the exposed flesh side. : PUTREFACTIVE DAMAGE;
3) vainness, in which branching lines of blood vessels can be seen on the flesh side. (If, because of poor curing or old age, for example, the structure around them becomes loose, the skin is said to be veiny, and the branching pattern of the veins usually shows through on the grain side. Veininess can actually at times be attractive in some skins, such as VELLUM.
4) damage from heat, which may occur on hides and skins in tropical areas. (It is a common fault with ground-dried skins. Sun Damage that occurs to a hide or skin when it becomes heated above a certain critical temperature while it is still moist and is laid out in the sun to dry (cure). A completely dry skin can become very hot and still not be affected under normal conditions of cure, but prior to this a skin is very susceptible to damage. Also, the drying of a salted skin proceeds so uniformly throughout its entire thickness that the cooling effect produced by evaporation off its surfaces maintains the temperature of the entire skin below the danger point until it is uniformly dry. Without salt, however, a skin tends to dry unevenly when laid out in the usual manner, which is flesh side up. This can happen because the flesh side can dry out completely and begin generating heat, while the underside remains moist, and, being shielded from evaporation, also begins to generate heat. This is especially the case when pieces of flesh, generally of a fatty nature, are present on the flesh side, and further retard the drying of areas beneath them.
How is Leather Made?
Many consumers own a variety of leather products, ranging from belts to jackets, and the resourceful material has been used for thousands of years in a variety of products. The process for making leather includes a complex set of steps from skin to finished product. These steps are often referred to as "tanning" due to the most typical part of the process, which uses the tannic acids present in plant matter to chemically modify the leather so that it will not decompose or rot.
If used without any treatment, animal hides would quickly break down and begin to stink. For this reason, the hide needs to be treated to form leather. The process can be broken down into two
basic stages: wet blue processing and finishing, both of which are adept in large commercial spaces known as tanneries. While it is possible to make leather at home, it is an aromatic and complicated process, and most people prefer to send out their hides for tanning.
Skin has three layers beginning with the epidermis, proceeding to the derma, and ending in the adipose, which is also known as flesh. When making leather, only the strong and flexible derma, which is a layer of collagen fibers, is preferred. The collagen is exuded by cells, and forms a network of useful strings. When leather is processed, these fibers are retained while everything else is stripped away.
First, the skin is fleshed, the flesh being cleaned off of the hide, and the surplus adipose, or animal fat, is removed. Then the hides are washed and soaked, which regain moisture to dried hides while loosening blood and dirt. Chemicals are added to turn the water alkaline, which will eat away at the hair and epidermis. The collagen fibers begin to swell, while excess proteins rushed out.
When this process is complete, the water is brought to a stable pH and the swelling goes down, so that enzymatic cleaners can be added to remove any remaining organic waste. Then the hide is pickled in a highly acidic solution, which prepares it for tanning. Tanning agents form bonds with the collagen in the hide, causing it to resist bacterial attack, and the hides are removed from the wet blue processing tank for finishing, after being run through rollers to remove excess water.
When the hides emerge from the wet blue stage, they are split to the preferred thickness. Depending on the planned use of the leather, this thickness may vary. Then the leather is re-tanned, with different materials depending on whether it needs to be firm or soft, and dyed. After dyeing, the leather is oiled so that it will remain flexible and soft. Then the leather is dried, mechanically treated to soften it, and buffed so that it will have a smooth and attractive surface. Some leathers are marked with patterns before the final stage, which is the function of a finishing coat of polymer or wax to protect the surface of the leather.
Leather treatment used to be a highly polluting industry, but tanneries responded to public protest about odor and pollution issues. Tanneries now recycle the liquids used in the leather making process and desist from chemical dumping. Tanning still carries a strong stink, but is no longer accompanied by environmentally unfriendly business practices in most parts of the world.
If used without any treatment, animal hides would quickly break down and begin to stink. For this reason, the hide needs to be treated to form leather. The process can be broken down into two
basic stages: wet blue processing and finishing, both of which are adept in large commercial spaces known as tanneries. While it is possible to make leather at home, it is an aromatic and complicated process, and most people prefer to send out their hides for tanning.
Skin has three layers beginning with the epidermis, proceeding to the derma, and ending in the adipose, which is also known as flesh. When making leather, only the strong and flexible derma, which is a layer of collagen fibers, is preferred. The collagen is exuded by cells, and forms a network of useful strings. When leather is processed, these fibers are retained while everything else is stripped away.
First, the skin is fleshed, the flesh being cleaned off of the hide, and the surplus adipose, or animal fat, is removed. Then the hides are washed and soaked, which regain moisture to dried hides while loosening blood and dirt. Chemicals are added to turn the water alkaline, which will eat away at the hair and epidermis. The collagen fibers begin to swell, while excess proteins rushed out.
When this process is complete, the water is brought to a stable pH and the swelling goes down, so that enzymatic cleaners can be added to remove any remaining organic waste. Then the hide is pickled in a highly acidic solution, which prepares it for tanning. Tanning agents form bonds with the collagen in the hide, causing it to resist bacterial attack, and the hides are removed from the wet blue processing tank for finishing, after being run through rollers to remove excess water.
When the hides emerge from the wet blue stage, they are split to the preferred thickness. Depending on the planned use of the leather, this thickness may vary. Then the leather is re-tanned, with different materials depending on whether it needs to be firm or soft, and dyed. After dyeing, the leather is oiled so that it will remain flexible and soft. Then the leather is dried, mechanically treated to soften it, and buffed so that it will have a smooth and attractive surface. Some leathers are marked with patterns before the final stage, which is the function of a finishing coat of polymer or wax to protect the surface of the leather.
Leather treatment used to be a highly polluting industry, but tanneries responded to public protest about odor and pollution issues. Tanneries now recycle the liquids used in the leather making process and desist from chemical dumping. Tanning still carries a strong stink, but is no longer accompanied by environmentally unfriendly business practices in most parts of the world.
DIFFERENT TYPES OF TANNING FOR LEATHER PREPARATION
Leather is made from animal skins or hides which have been chemically treated to preserve quality and natural beauty. The chemical procedure used to ready raw animal hides for use is called "tanning."Tanning is the process of making leather, which does not easily decompose, from the skins of animals, which do. Often this uses tannin, an acidic chemical compound. Coloring may occur during tanning
VEGETABLE TANNING
Hides which have been tanned with a vegetable tanning agent solution produce flexible, but stiff leathers, such as those used in luggage, furniture, leashes, belts, hats, and harnesses.
Vegetable tanning consists of stringing hides on large frames, located inside large vats, and exposing them to tannin, a natural product found in the bark, wood, leaves and fruits of chestnut, oak and hemlock trees. Hides are transferred to many different bins during this step, each containing a stronger solution of tannin. Vegetable tanning prevents the skin from decay and shrinkage.
MINERAL TANNING
Mineral or chrome tanning is performed on skins which will be used for softer, stretchier leathers, such as those found in purses, bags, briefcases, shoes, gloves, boots, jackets, pants, and sandals.
Hides which are tanned with minerals are pickled first in an acid and salt mixture. From there, hides are soaked into a chromium-sulfate solution. This process is much faster than vegetable tanning, and is usually a 1-day project. . It is also known as wet-blue for its color derived from the chromium. More esoteric colors are possible using chrome tanning.
Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds. This is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the main type of "chrome-free" leather, often seen in shoes for infants, and automobiles. Formaldehyde tanning (being phased out due to its danger to workers and the sensitivity of many people to formaldehyde) is another method of aldehyde tanning. Brain-tanned leathers fall into this category and are exceptionally water absorbent. Brain tanned leathers are made by a labor-intensive process which uses emulsified oils, often those of animal brains. They are known for their exceptional softness and their ability to be washed. Chamois leather also falls into the category of aldehyde tanning and like brain tanning produces a highly water absorbent leather. Chamois leather is made by using oils (traditionally cod oil) that oxidize easily to produce the aldehydes that tan the leather to make the fabric the color it is
Synthetic-tanned leather is tanned using aromatic polymers such as the Novolac or Neradol types. This leather is white in color and was invented when vegetable tannins were in short supply, i.e. during the Second World War. Melamine and other amino-functional resins fall into this category as well and they provide the filling that modern leathers often require. Urea-formaldehyde resins were also used in this tanning method until dissatisfaction about the formation of free formaldehyde was realized.
Alum-tanned leather is tanned using aluminium salts mixed with a variety of binders and protein sources, such as flour, egg yolk, etc. Purists argue that alum-tanned leather is technically "tawed" and not tanned, as the resulting material will rot in water. Very light shades of leather are possible using this process, but the resulting material is not as supple as vegetable-tanned leather
Oil tanning
The familiar wash leather (chamois or ‘chammy’)is tanned with unsaturated oil and the preferred agent is cod lever oil. Useful tanning oils contain fatty acids,either free or as glyceride derivates, which are poly unsaturated. The degree of unsaturation is critical, because if there is too little unsaturation the oil will not oxidize readily and therefore function only as lubricant, if there is too much unsaturation the oil will crosslink itself and harden with oxidation,like linseed oil.
VEGETABLE TANNING
Hides which have been tanned with a vegetable tanning agent solution produce flexible, but stiff leathers, such as those used in luggage, furniture, leashes, belts, hats, and harnesses.
Vegetable tanning consists of stringing hides on large frames, located inside large vats, and exposing them to tannin, a natural product found in the bark, wood, leaves and fruits of chestnut, oak and hemlock trees. Hides are transferred to many different bins during this step, each containing a stronger solution of tannin. Vegetable tanning prevents the skin from decay and shrinkage.
MINERAL TANNING
Mineral or chrome tanning is performed on skins which will be used for softer, stretchier leathers, such as those found in purses, bags, briefcases, shoes, gloves, boots, jackets, pants, and sandals.
Hides which are tanned with minerals are pickled first in an acid and salt mixture. From there, hides are soaked into a chromium-sulfate solution. This process is much faster than vegetable tanning, and is usually a 1-day project. . It is also known as wet-blue for its color derived from the chromium. More esoteric colors are possible using chrome tanning.
Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds. This is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the main type of "chrome-free" leather, often seen in shoes for infants, and automobiles. Formaldehyde tanning (being phased out due to its danger to workers and the sensitivity of many people to formaldehyde) is another method of aldehyde tanning. Brain-tanned leathers fall into this category and are exceptionally water absorbent. Brain tanned leathers are made by a labor-intensive process which uses emulsified oils, often those of animal brains. They are known for their exceptional softness and their ability to be washed. Chamois leather also falls into the category of aldehyde tanning and like brain tanning produces a highly water absorbent leather. Chamois leather is made by using oils (traditionally cod oil) that oxidize easily to produce the aldehydes that tan the leather to make the fabric the color it is
Synthetic-tanned leather is tanned using aromatic polymers such as the Novolac or Neradol types. This leather is white in color and was invented when vegetable tannins were in short supply, i.e. during the Second World War. Melamine and other amino-functional resins fall into this category as well and they provide the filling that modern leathers often require. Urea-formaldehyde resins were also used in this tanning method until dissatisfaction about the formation of free formaldehyde was realized.
Alum-tanned leather is tanned using aluminium salts mixed with a variety of binders and protein sources, such as flour, egg yolk, etc. Purists argue that alum-tanned leather is technically "tawed" and not tanned, as the resulting material will rot in water. Very light shades of leather are possible using this process, but the resulting material is not as supple as vegetable-tanned leather
Oil tanning
The familiar wash leather (chamois or ‘chammy’)is tanned with unsaturated oil and the preferred agent is cod lever oil. Useful tanning oils contain fatty acids,either free or as glyceride derivates, which are poly unsaturated. The degree of unsaturation is critical, because if there is too little unsaturation the oil will not oxidize readily and therefore function only as lubricant, if there is too much unsaturation the oil will crosslink itself and harden with oxidation,like linseed oil.
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