Thursday, 5 April 2012

Elephant No. 186: Leather Stamping

In my ongoing quest to sort and contain a wealth of art and craft supplies, I came across a box of leather scraps from various theatrical projects, so today I thought I'd try leather stamping.

Leather comes from tanning the hides of various animals. This usually means cattle, although the type of hide often depends on what animals are locally raised and available. Hides have been tanned for millennia, usually involving three major stages: cleaning the hide of flesh and hair; soaking it in some kind of solution; then stretching the hide as it dries. During the tanning process, dyes may also be added, and various finishes can be given to the hide through processes such as embossing, polishing, rolling, and so forth.

Different tanning solutions have different effects on leather. The earliest leathers were processed with vegetable-based substances such as tree bark. These solutions contained tannins; hence hide-tanning. Vegetable-tanned leathers tend to be somewhat unstable, and can become brittle over time. If immersed in hot water, vegetable-tanned leather becomes hard, and was sometimes used to make armour.

Chrome-tanned leather, invented in 1858, uses chromium salts, and is more supple than vegetable leather. Aldehyde-tanned leather includes leather produced with formaldehyde, and brain-tanned leather, which involves the use of emulsified oils in the form of animal brains. Brain-tanned leather is soft and washable, and is often used in traditional Native American clothing and footwear. Chamois is produced in a similar fashion, usually with cod oil.

Rose-tanned leather is one of the more unusual types, combining both vegetable tanning and aldehyde tanning. Instead of vegetable matter, formaldehyde, animal brains or cod oil, this process involves attar of roses. Rose-tanned leather is considered the most valuable on Earth, due to the high cost of attar of roses and a particularly labour-intensive tanning process.

Traditional leather-tanning in Fez, Morocco, 2005.
Photo: Bernard Gagnon

Other materials used to tan leather include polymers, resins and alum. Vegetable tanning remains the most common form of leather processing today, although resins and polymers are also used.

Leather comes in a number of different forms:

Full-grain leather is hide that has not been buffed or sanded to remove imperfections. The grain is breathable and will develop a patina over time. High-end footwear and furniture are generally made of full-grain leather.

Top-grain leather is the second-best leather, and is the type commonly used in good-quality leather products. The "split" layer (see below) has been sliced away, making top-grain leather thinner and more flexible than full-grain leather. It has also been sanded and has a finish coat, which makes it less breathable, and it will not develop a patina over time.

Corrected-grain leather is any leather that has had false grain added to its surface. Imperfections in the hide have been sanded or otherwise fixed, and an artificial grain has been imprinted into the surface, which has also been dyed or stained.

Split leather is leather produced from the fibrous part of the hide, once the top grain has been removed. Split leather will then either have an extra layer applied to the surface and embossed with a false leather grain, or used as suede.

Buckskin or brained leather is smooth, velvety leather that has been tanned with animal brains or other fatty substances, then heavily smoked to keep it from rotting. This is the the leather most commonly used for traditional clothing in many indigenous cultures.

Patent leather is leather with a glossy finish. Today, patent leather usually has a plastic coating as well.

Bonded leather is essentially reconstituted leather made of scrap leather fibres from mills and tanneries, bonded together to look like leather. It is not terribly durable, although it is commonly used in furniture.

Lancet container made with shagreen,
or stingray leather, late 18th century.

Although most leathers come from cattle, leather is also commonly made from lambs, goats, deer, moose, elk, pigs, buffaloes, goats, alligators, stingrays, dogs, lizards, eels, snakes, ostriches, kangaroos—and yes, even elephants.

Wallet made with ostrich leather.

Leather stamping involves making an imprint by tapping a metal die or stamp into a piece of leather. For today's elephant, I pulled out this set of cold steel letter stamps I bought a few years ago to use in silversmithing. I've never tried leather stamping or tooling before, but I figured these might work.

For a hammer, I thought a light touch was probably called for, so I used this small chasing hammer, also from my silversmithing toolbox.

I chose to use just the "E" from the set to make my elephant.

From the box of leather scraps I'd unearthed, I chose a couple of thick pieces with a smooth but not shiny surface.

I didn't really know what I was doing, but the instructions all said that the leather needs to be dampened. This apparently makes it soft enough to yield to the stamp. It can't be too damp, however, or the leather becomes weak. I started with the lighter piece, and dampened it by simply running a wet paper towel across it. The water soaked in right away, leaving it damp, but not sopping.

I started fairly tentatively, smacking the die with a light tap using my little hammer. One thing I realized right away that it was going to be difficult to draw something using stamps. There must be a way to mark things beforehand, but I must admit that I didn't really try to find out.

So far, so good, so I got a bit bolder. One thing I noticed was that, wherever the leather was drying out, the punch bit into the leather in a way that was less imprinting and more cutting. However, if you dampen the leather again, the grain absorbs the water and puffs up, reducing the depth of the imprint. A conundrum.

I was happy enough with the way this one turned out, and it took only about ten minutes, so I decided to try another.

I used the darker leather for the next one.

This time it was a lot easier, so it went even faster. This leather was a little thinner than the first stuff, so it began drying out a little more quickly.

This whole process went way faster than I expected, and it was pretty easy. To keep the imprints, I'll have to coat both of these with some kind of leather preservative, such as mink oil, which will help to waterproof the leather and keep it from plumping up if gets damp. I'll definitely try this again sometime, perhaps as a way to decorate a bracelet or a belt.

Elephant Lore of the Day
Elephant leather appears relatively easy to come by. Reputable dealers in elephant leather acquire it through means allowed under the strict Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). These include natural death and the periodic culling of herds in Africa.

Most elephant hide comes from the sides of the body, although skin from the ears and trunk is also used. The hide from the elephant's ears, in particular, is thinner and smoother than body panels, and is primarily used in wallets and, oddly, pool cues. Elephant hide comes in many grains, although the deeper the grain, the thicker the skin. Elephant hide is primarily used to make footwear, custom car interiors, jackets, upholstery and jewellery.

According to one of the more reputable dealers in exotic leathers, elephant hides are usually a by-product of seasonal killings by tribal peoples—similar to deer season in North America. As such, the use of elephant hide is not seen to be creating or feeding a demand the way that ivory does, but simply ensuring the fullest use of the elephant's body.

Elephant leather from Rojé Exotics, U.S.A.

1 comment:

  1. High quality post. If you have any tips site mostly tips for tanning site then share with me. I am waiting for you.