A Quality Leather Watchband – Sounds Simple?
A quality leather watch band sometimes seems an impossible item to find. The thing is, with a few key questions, buying a quality watchband becomes a lot easier. The question is, what are those questions? A lot goes into making a leather watchband – the first is the leather itself, so that is where we will start.
Leather comes in many different forms. You can easily see this when you start looking for a new watchband. So we know what we are talking about; it is crucial. Leather is the skin of an animal, the most common is cowhide, which is processed to become a functional material. The skins of almost any animal can be transformed into leather, including snakes, birds, and fish.
What Is Leather?
The key attribute that distinguishes a “leather” from an “animal skin” is that leather does not rot or smell in use. The process of changing an animal’s skin from the rotting flesh that is waste from the slaughterhouse into the fine material most of us use daily is called “leathering,” or more technically, denaturing. The goal of denaturing the skin is to stop the decay process, transforming it into a useful material. This denaturing of the skin is achieved through the tanning process, which permanently alters the protein structure of the skin.
The process is called tanning. It is believed that this is because the first tanning processes relied on the skins being stretched in the sun and they became tanned through prolonged exposure to the sun. Unfortunately, these primitive attempts at tanning did not stop the decay process; it merely slowed it, so over time, the tanned skins would start to smell and slowly fall apart.
Tanning, The First Step To Leather
Thankfully tanning has moved on a long way since those early days, and the science is well understood, although tanning remains more of an art than a science. The problem is that each skin is different, so the tanner’s skill will ultimately determine the quality of the signal leather.
Please make no mistake about it; the process to create a beautiful piece of leather to hold your watch on your wrist is quite brutal. The result is one of the most gorgeous materials that is robust, resilient, and magnificent to look at. How it this achieved?
Getting The Skins To The Tannery
At the slaughterhouse, the hides are seen as a waste product. The hides are covered in salt and packed for transport to the tannery. Packing the hide in salt slows the decay process and preserves it until it makes it to the tannery, which can be a surprisingly long time. Interestingly, there is an international trade in salted hides, so even though the hide was tanned in a specific country, it does not mean that the animal originated from that country.
When the skin arrives at the tannery, its first stop is the beam house. The skins are shaken free of the salt, washed, and then soaked in a highly alkaline solution. The alkaline solution starts to attack the fats and hair on the skin. After soaking for a suitable time, the skins are scraped on the skin side to remove the hair and the flesh side to remove the fat that remains. In less industrial times, this process was performed by hand, and the skin was cleaned by placing the skin over a large beam and scraping with a scraper, hence the name of this process, the beam house process.
The cleaned skin is now ready to start the tanning process. There are two very distinct methods for tanning leather, and they result in very different properties in the finished leather. One uses industrial chemicals for the process, and the other uses more natural chemicals, effectively a very strong tea.
The industrial tanning process is sometimes referred to as mineral tanning. The name is useful because various mineral salts can be used for tanning, but they all follow the same process. Here we will focus on the most common two, chromium tanning and aluminum tanning.
In the second stage of the tanning process, the skins are loaded into a large drum that is effectively a vast washing machine. The drum tanning solution is added, and the skins and the tanning solution are rotated together in the drum. The exact tanning solution will depend on the specific use of the leather, but as mentioned earlier, the most common salt is chromium salt. Aluminum salts are generally used for leather that will be worn against the skin; the reason for this will become evident a little later in this post.
The drum rotates for several hours, agitating the hides and the tanning solution so the solution can penetrate the entire thickness of the skins. The exact length of time will depend on a whole host of variables, including the thickness of the hides, the temperature in the tannery, and the concentration of the tanning solution, to name but a few. Timing the exact tanning process is where the artisanal skill of the tanner is essential.
The Tanned Leather Is Not As Expected
Once the process is complete, the leather is wet, slimy and if a chromium salt were used, it would have a very distinctive blue hue. The hides at the end of this process are referred to as “wet blue.” Again, just like the salted hides, wet blue is traded internationally. The original provenance of the leather becomes even less clear. If the skins have been tanned with an aluminum salt, they are referred to as “wet white” as the aluminum salt turns the hides white.
The second way to tan a hide is called vegetable tanning. As the name suggests, the hides are tanned using vegetable extracts. The solution can be thought of as a very strong tea brewed from vegetable extracts high in tannins. Whereas in mineral tanning, the chromium or the aluminum salts are the reactive agents, the active agents are the tannins in vegetable tanning.
The vegetable tanning process proceeds by submerging the hides into large vats of the tanning solution. The hides are left immersed in the solution until the tanning solution has penetrated the entire hide thickness; this can take days. The finished product is again a slippery slimy skin but is generally a tea brown color. The leather is referred to as vegetable crust at this stage and, likewise, is traded globally.
How Does This Help To Find A Quality Leather Watchband?
When buying a watchband, it is essential to understand the chemicals used in the tanning process, as the watch band will be against your skin for many hours. Our skin is a porous organ, so impurities from the watch band can, once dissolved in sweat, be transported onto your skin and then into your body. Also, some people do have susceptible skin, and the tanning chemicals can exacerbate this.
Let’s start with the elephant in the room. Chromium salts can be hazardous, causing nasty side effects ranging from compromising your immune system to heavy metal poisoning and cancer. But, as with all things in life, it is not quite that simple.
The Chromium Conundrum
There are two distinctive states for chromium salts: Chromium Six (Cr6) and Chromium Three (Cr3). We don’t need to worry about the details, but the three and the six refer to the valence state of the chromium ion. If you want to know more, write a comment below, and I will keep going down this wormhole!
Cr3 is necessary for our survival. We all have Cr3 in our bodies and is an essential micronutrient for our health. It is when is Oxidises to Cr6 that all the trouble starts. Cr3 is in a very stable environment in our bodies, so there is no chance of it oxidizing to Cr6. That is not the case in general use out in the world. That is why all chrome tanned leather needs to go through extensive testing to confirm there is no Cr6 present in the final leather when it leaves the tannery. Unfortunately, there can still be further reactions over time. This is why chrome tanned leather is no longer permitted for use where the leather comes into contact with human skin, such as gloves and shoe linings. The advent of these regulations was one of the forces driving the development of aluminum tanning. There are drawbacks to switching to aluminum tanned leather – more on that later.
Vegetable Tanning Is Not All Plain Sailing
Vegetable-tanned leather removes the issue from Cr6 and because it uses tree and bark extract. Nothing could cause an allergic reaction, except the tannins are acidic, and they can cause a skin reaction on very few people with, susceptible skin. The other problem is because vegetable tanning is such a time-consuming process, it costs a lot more than chromium tanning.
For the watch enthusiast, where does that leave us?
The key takeaway from all this is that there are two specific ways to tan leather, either through mineral salts (chromium or aluminum predominantly) or vegetable tanning. You do not want to wear chromium-tanned leather against your skin. Vegetable-tanned leather would seem ideal as it is just animal hides steeped in strong tea. So, if we make all our watch bands from vegetable-tanned leather, everything will be okay?
It Is All About What Comes Next
Not entirely. The problem is in the tanning process; the animal skin has just had its protein structure altered so that it will not decompose quickly. At the end of both vegetable and mineral tanning processes, we have a slimy mess. The next step, the finishing of the leather, is critical to its final look and performance. The various finishing processes and the final finishes are determined by the tanning process.
Alas, nothing is ever easy!
Next time I will go into the finishing of the leather, where it is transformed from the slimy denatured hide and becomes a beautiful watch band. And in the process, you will understand how to identify the best watchbands. In the meantime, if you have any specific questions on watchbands, put them in the comments below and I will do my best to answer them.