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WHY AND HOW TO CARE FOR LEATHER We are all familiar with leather and its origins, how together with wood it formed the basis of much ancient technology. Leather, due to its excellent abrasion and wind resistance, found a use in rugged occupations. The image of a cowboy in leather chaps gave way to the leather-jacketed and leather-helmeted aviator. When motorcycles were invented, some riders took to wearing heavy leather jackets to protect from grazing and wind blast; some also wear chaps or full leather trousers to protect the lower body. Many sports still use leather to help in playing the game or protecting players: due to its flexible nature it can be formed and flexed for the occasion. Today, most leather is made of cow hides, but many exceptions exist. Lamb, pig and deer skin are used for soft leather in more expensive apparels. Kangaroo leather is used to make items which need to be strong but flexible, such as motorcycle gloves. Kangaroo leather is favoured by motorcyclists specifically because of its lighter weight and higher abrasion resistance compared to cowhide. LEATHER STRUCTURE Before we can care for leather successfully we firstly have to understand its structure and what it actually consists of. Close investigation reveals it as a naturally “woven” material consisting of 76% protein, 14% water and 10% fat. Below the surface grain, the protein layer of stabilised collagen is arranged in a spaghetti type structure which gives the leather its strength, flexibility and durability. This under layer is more absorbent than the surface and benefits from regular conditioning and cleaning. Neglect allows the entry of dirt and results in abrasion cracking and ultimately breaking down the leather. Cared for leather goods can remain fully functional and in good condition for many years. Converting this hide at a tannery, regularly monitoring its ph and transforming it into usable finished leather can take in excess of two weeks of processing. At the end of this time the finished leather is usually given a series of finishing treatments including a final treatment of fluorocarbon to aid ultimate water repellency.
Vegetable-tanned leather is tanned using tannin (hence the name "tanning") and other ingredients found in vegetable matter, tree bark, and other such sources. It is supple, usually brown in colour, with the exact shade depending on the mix of chemicals and the original colour of the leather. Vegetable-tanned leather is not stable in water; it tends to discolour, and if left to soak and then dry it will shrink and become less supple and harder. 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. Rawhide is made by scraping the skin thin, soaking it in lime, and then stretching it while it dries. Like alum-tanning, rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather, and is primarily used in drum heads where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching. Chrome-tanned leather, invented in 1858, is tanned using chromium sulphate and other salts of chromium. It is more supple and pliable than vegetable-tanned leather, and does not discolour or lose shape as drastically in water as vegetable-tanned. More unusual colours are possible using chrome tanning. LEATHER TYPES Leather (usually vegetable-tanned leather) can be oiled or waxed to improve its water resistance. This supplements the natural oils remaining in the leather itself, which can be washed out through repeated exposure to water. Frequent treatment of leather keeps it soft and supple and improves its lifespan dramatically. However for leather uses like in walking boots where the over softening of leather is detrimental to their ultimate performance oils are not recommended but specialist waxes are preferred. Full-Grain leather is made from the finest raw material of clean natural hides which have not been sanded to remove imperfections, only the hair has been removed. The grain remains in its natural state which will allow the best fibre strength, resulting in greater durability. The natural grain also has natural breathability, resulting in greater comfort and will wear better than other leather. Rather than wearing out, it will develop a natural "Patina" and grow more beautiful over time. The finest furniture, and footwear, are made from Full Grain leather. Corrected-Grain Leather Corrected Leather is rough on one side and smooth on the other. The smooth side is the side where the hair and natural grain used to be. These hides, which are made from inferior quality raw materials, have all of the natural grain sanded off, and an artificial grain applied. Top grain leather generally must be heavily painted to cover up the sanding and stamping process. Suede is an interior split of the hide and is rough on both sides. Suede is less durable than top-grain but is cheaper because many pieces of suede can be split from a single thickness of hide, whereas only one piece of top-grain can be made. However, manufacturers use a variety of techniques to make suede appear to be full-grain. For example, in one process, glue is mixed with one side of the suede, which is then pressed through rollers; these flatten and even out one side of the material, giving it the smooth appearance of full-grain. Cattle hide leather buffed on the grain side to give a velvety surface is known as Nubuck leather and should be treated in the same way as Suede. In creating this finish lower grades of hide can be used to keep pricing competitive against the use of full grain leather. There are two other descriptions of leather more commonly used in speciality products, such as briefcases, wallets, and luggage. Belting leather is full grain leather that was originally used in driving pulley belts and other machinery. It is often found on the surface of briefcases, portfolios, and wallets, and can be identified by its thick, firm feel and smooth finish. Belting leather is the only kind of leather used in luxury products that can retain its shape without the need for a separate frame; it is generally a heavy weight of full-grain, vegetable-tanned leather. Nappa leather, is extremely soft and supple, and is commonly found in high quality car upholstery, wallets, toiletry kits, and other personal leather goods. CLEANING AND CONDITIONING After using smooth leather items rinse or wipe over with a damp cloth
then allow to dry naturally. Speciality light coloured leathers as used
in car seats should be vacuumed first to remove dust prior to wiping
over. Failure to do this, results in the dust being absorbed into the
stitching and turning it an unsightly grey colour. Ideally you should
store leather items at room temperature in a well ventilated room. High
temperatures dry out leather causing cracking and low temperatures encourage
the growth of mildew. Mould and mildew thrive in warm, dark, damp conditions.
Penetrating deep into the leather they can weaken the fibres causing
permanent damage. These mould spores will migrate to other items if stored
together. Wipe over and treat with Storm silver based anti-bacterial
spray to prevent further contamination. It is impossible to repair damage
already done but treatment will cause the spores to lie dormant. WET LEATHER CARE Always prevent leather becoming saturated by using the correct conditioning
treatments from new. Soft leather or leathers that need to remain supple
should be initially treated with a Storm Conditioning or Waterproofing
spray but leathers used in a more testing environment like those used
in walking boots should be treated with Storm Leather Conditioning Cream.
Should leather become accidentally saturated it could easily stretch
and become weakened, use the Storm conditioning treatment on the leather
before it becomes fully dry and then allow it to continue drying naturally.
Apply a further light treatment to the leather when it is fully dry. DRY LEATHER CARE Although most people consider that leather should be preserved by creating
a barrier against water on its surface, hot conditions are equally as
threatening to its long term performance. The natural fibres of leather
will break down with the passage of time. Acidic leathers are particularly
vulnerable to a type of rot that is aggravated by high temperatures and
relative humidities, and is irreversible. This rot is caused by prolonged
storage or exposure to high relative humidity, environmental pollution,
and high temperature. In particular, it occurs at pH values of 4.2 to
4.5. Sulphur dioxide converts to sulphuric acid which forms hydrogen
peroxide. The peroxide combines with residual tannins in the leather
to oxidize proteins, creating ammonium sulphate and ammonium bisulphate.
This manifests itself as a characteristic powdering of the leather's
surface, along with structural weakness through loss, delamination, and
a possibly felt-like consistency. Exposure to long periods of low relative
humidities (below 40%) can cause leather to become desiccated, irreversibly
changing the fibrous structure of the leather. Foot odour has always been associated with all sports activities but
actually affects all footwear use. Even open toed leather sandals can
give rise to smells when constructed together with man made soles.
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