CHAPTER TWO

HIDES AND THEIR TREATMENT

If we examine our shoes, we will find that the different parts are composed of material called leather. The bottom of the shoe is of hard leather, while the part above the sole is of a softer, more pliable leather. This leather is nothing more than the hides of different animals treated in such a way as to remove the fat and the hair.

After the hides have been taken from the dead body of the animal, they are quite heavily salted to preserve them from spoiling. In this salted condition they are shipped to the tanneries.

The process or series of processes by which the hides and skins of animals are converted into leather is called tanning. The process may be divided into three groups of subprocesses as follows:--

Beamhouse process, which removes the hair from the hides and prepares them for the actual process of the tanning or conversion into leather; tanning, which converts the raw hide into leather; and finishing, which involves a number of operations, the objects of which are to give the leather the color that may be desired and also to make it of uniform thickness, and impart to it the softness and the finish that is required for a particular purpose.

Hides are divided roughly in the tannery, according to the size, into three general classes:--

(1) Hides, skins from fully grown animals, as cows, oxen, horses, buffaloes, walrus, etc. These are thick, heavy leather, used for shoe soles, large machinery belting, trunks, etc., where stiffness, strength, and wearing qualities are desired. The untanned hides weigh from twenty-five to sixty pounds.

(2) Kips, skins of the undersized animals of the above group, weighing between fifteen and twenty-five pounds.

(3) Skins from small animals, such as calves, sheep, goats, dogs, etc. This last group gives a light, but strong and pliable leather, which may be used for a great many purposes, such as men’s shoes and the heavier grades of women’s shoes.

The hides, kips, and skins are divided into various grades, according to their weight, size, condition, and quality.

The quality of the hides not only depends upon the kind of animal, but also upon its fodder and mode of living. The hides of wild cattle yield a more compact and stronger leather than those of our domesticated beasts. Among these latter the stall-fed have better hides than the meadow-fed, or grazing cattle. The thickness of the hide varies considerably on different animals and on the parts of the body, the thickest part of the bull being near the head and the middle of the back, while at the belly the hide is thinnest. These differences are less conspicuous in sheep, goats, and calves. As regards sheep, it would appear that their skin is generally thinnest where their wool is longest.

In the raw, untanned state, and with the hair still on, the hides are termed “green” or “fresh.” Fresh, or green hides are supplied to the tanners by the packers or the butchers, or are imported, either dry or salted.

Hides are obtained either from the regular packing houses or from farmers who kill their own stock, and do not skin the animal as scientifically as the regular packing houses, in which case they are called country hides. There are different grades of hides and leather, and these different grades are divided in the commercial world into the five following grades:--

I. NATIVE HIDES

Native Steers Native Cows, heavy Native Cows, light Branded Cows Butts Colorado Steers Texas Steers, heavy Texas Steers, light Texas Steers, ex-light Native Bulls Branded Bulls

II. COUNTRY HIDES

Ohio Buffs Ohio Ex. Southerns

III. DRY HIDES

(Raised on plain. Rough side suitable for soles.)

Buenos Ayres

IV. CALFSKINS

(Green salted)

Chicago City

V. PARIS CITY CALFSKINS

Light Medium Heavy

Hides obtained from steers raised on Western farms are known as native steer hides.

Native cowhide (heavy) is hide weighing from fifty-five to sixty-five pounds, obtained from cows.

Native cowhide (light) is cowhide weighing under fifty-five pounds.

Branded cowhide is hide obtained from cows that are branded on the face of the hide.

Butts is a term applied to the part of the hide remaining after cutting off the head, shoulders, and strip of the belly.

Colorado steer hide is from Colorado steers, which are very light.

Texas steer hide comes in three grades, heavy, light, and extra light. The heavy grade is very heavy because the animal is allowed to graze on the plains. That is the reason why it is heavier than the Colorado steer hide, which is raised on the farm.

Bull hide is divided into two classes, the regular hide and the branded grade. The branded grade usually is one cent a pound less than the regular.

Country hides are of three grades, Ohio Buffs, Ohio Ex., and Southern. The Ohio Buffs weigh from forty to sixty pounds. The Ohio Ex. weighs from twenty to forty pounds. Southern hides have spots without hair and other blemishes on them, due to the sting of insects. This makes the Southern hide inferior to the Ohio, Indiana, Michigan, and Chicago hides that have no such blemishes. Ohio Butt hides are the best, because in Ohio they kill a great many young calves, while in Chicago young cows (that have calved) are killed, causing the hide to be flanky.

The season of the year in which cattle are slaughtered has considerable influence upon both the weight and condition of the hide. During the winter months, by reason of the hair being longer and thicker, the hide is heavier, ranging from seventy-five to eighty pounds, and gradually decreasing in weight as the season becomes warmer and the coat is shed, until in June and July it weighs from seventy down to fifty-five pounds, the hair then being thin and short. The best hides of the year are October hides, and short-haired hides are better for leather purposes than long-haired ones.

A thick hide which is to be used for upper leather is cut into sides before the tanning process is completed. This is performed by passing it between rollers where it comes in contact with a sharp knife-edge, which splits it into two or more sheets. Great care must be exercised in cutting the leather in order to have good “splits” (sheets of leather). A split from a heavy hide is not as good as a whole of a lighter leather.

Butts and backs are selected from the stoutest and heaviest oxhides. The butt is formed by cutting off the head, the shoulder, and the strip of the belly. The butt or back of oxhide forms the stoutest and heaviest leather, such as is used for soles of boots, harness, etc.

Hides and skins are received at the tannery in one of three conditions, viz. green-salted, dry, or dry-salted. Very few hides are received by tanners in fresh or unsalted condition, salt being necessary to preserve them from decay. Green-salted hides are those that have been salted in fresh condition, tied up in bundles, and shipped to the tanner. Dry hides are those that were taken from the carcass and dried without being salted; these are usually stiff and hard. Dry-salted hides are hides that were heavily salted while they were fresh, and then dried. The hides and skins that are received from the slaughterhouses of this country are almost invariably green-salted; those from foreign countries are green-salted, dry, and dry-salted.

It does not matter in what condition the hides are received or the kind of leather into which they are to be tanned; they all require soaking in water before any attempt is made to remove the hair or to tan them. The object of the soaking process, as it is called, is to thoroughly soften the hides and to remove from them all salt, dirt, blood, etc. Ordinary hides are usually soaked from twenty-four to forty-eight hours. Dry hides require much longer. The water should be changed once or twice during the process, since dirty water may injure the hides. Soft water is better than hard for this process. Where the water is hard, it is customary for the tanner to add a quantity of borax to it to increase its cleansing power and to hasten the softening of the hides.

When dry hides have become soft enough to bend without cracking, they are put into a machine and beaten and rolled, then soaked again until they are soft and pliable. It is very important that all the salt and dirt are removed during the process of soaking, as they injure the quality of the leather if they are not removed before the hides are unhaired. When the soaking process is completed, the lumps of fat and flesh that may have been left on by the butcher are removed by hand or by a machine, and the hides are then in condition to be passed along into the next process. The parts that cannot be made into leather, such as tails, teats, etc., are trimmed off before the hides are soaked. Large hides are cut into two pieces or halves, called “sides,” after they have been soaked.

For the purpose of taking the hair from the hides and skins, lime, sulphide of sodium, and red arsenic are used. Lime is sometimes used alone, but usually one of the other two chemicals is mixed with it. The lime is dissolved in hot water, a quantity of either sulphide of sodium or red arsenic is added to it, and the solution is then mixed with water in a vat, the hides being immersed in this liquor until the hair can be easily removed. The action of the unhairing liquor is to swell the hides, then to dissolve the perishable animal portion and loosen the hair so that it can be rubbed or pulled off.

There are several different processes of unhairing the hides. Each tanner uses the process that will help to give the leather the qualities that it should have, such as softness and pliability for shoe and glove leather, or firmness and solidity for sole and belting leather. This is one of the most important in the series of tannery processes, and if the hides are not unhaired properly and not prepared for tanning as they should be, the leather will not be right when it is tanned and finished.

There is also a process of unhairing, called “sweating,” which softens the hide and loosens the hair so that it can be scraped off. In this process the hides begin to decay before the hair is loose; it is therefore a dangerous process to use and must be carefully watched or the hides will be entirely spoiled. Sweating is never used for the finer, softer kinds of leather. It is applied chiefly to dry hides for sole, lace, and belt leather. It is an old-fashioned process and is not used as much nowadays as some years ago.

The pelts of sheep are salted at the slaughterhouses and then shipped to the tannery. Here they are thrown into water and left to soak twenty-four hours to loosen the dirt and dissolve the salt. The pelts are next passed through machines that clean the wool, and any particles of flesh remaining on the inner or flesh side are removed. The pelts are then in condition to have the wool removed. As long as a sheepskin has the wool upon it, it is called a pelt; as soon as the wool has been taken off, it is called a skin or a “slat.”

Each pelt is spread out smoothly on a table with the wool down and the inner or flesh side up. A mixture of lime and sulphide of sodium is next applied uniformly over the skin with a brush. The pelt is then folded up and placed in a pile with others. The solution that was applied penetrates the skin and loosens the wool, which, at the end of twenty-four hours, more or less, can be easily pulled off with the hands or rubbed off with a dull instrument or stick. The workman must be careful not to get any of the solution on to the wool, as it dissolves it and makes it worthless. Since the wool is valuable, the solution must be applied to the flesh side very carefully so that it does no injury. The wool that is removed from the skins is called “pulled wool.”

The slat is now ready to be limed, washed, pickled, and tanned. Heavy skins are often split into two sheets after they have been limed. The part from the wool side is called a skiver, and that from the flesh side is called a flesher.

After the skins have been limed, they are bated and washed, which makes them soft, clean, and white; they are then put into a solution of salt, sulphuric acid, and water, called “pickle,” and after a few hours they are taken out, drained, and tanned.

Large quantities of sheepskins are sold to tanners in the pickled condition by those who make a business of preparing such skins and selling the wool. Pickled skins can be kept an indefinite length of time without spoiling; they can also be dried and worked out into a cheap white leather without any further tanning whatever. Most of such skins, however, are sold to tanners, who tan them into leather. Sheepskins contain considerable grease, which must be removed before the leather can be sold.

For some processes of tanning, calfskins, goatskins, and cattle hides are also pickled the same as sheepskins; for other processes they are not pickled, but are thoroughly bated or delimed, washed, and cleansed. Heavy hides are sometimes split out of the lime; more frequently, however, they are not split until after they have been tanned.

To capitulate, the preparatory processes may be briefly described as follows:--

Soaking, which dissolves the salt, removes the dirt and makes the hides soft and comparatively clean.

Liming and unhairing, which swell the hides and dissolve the perishable animal portion, loosen the hair, and put the hides into proper condition for tanning. Hides tanned without liming, even if the hair is removed by some chemical, do not make pliable leather, but are stiff and hard.

Bating, which removes the lime from the hides.

Pickling, which helps in the tanning later, and keeps the hides and skins from spoiling if they are not tanned at once.

The lumps of fat and flesh that may be on the hides are removed by machinery or by placing the hide over a beam and scraping it with a knife. The hair, when it is loosened by the lime, is removed by a machine or by hand.