This is part two of three on our story on composites in watchmaking. Part 1 saw watch editor Ashok go into the nitty gritty of what composites are and how they figure in watchmaking. Part 2 runs through in brief the history of composite materials throughout human civilisation while Part 3 will feature contemporary use of composites and recent engineering feats in watchmaking.
More than The Sum of Its Parts
As much as we might think of composite materials as something futuristic or cutting edge, they have really been with us for the entirety of settled human civilization. You might not think it looking at your carbon watch today, but it is the descendant of ancient engineering from Egypt, Mesopotamia and, quite possibly, all cultures that thought of combining cut straw with mud to form bricks. Long before materials science got into the act, our ancestors had figured out that you could get stronger and more durable materials by combining a couple of materials and exposing them to a set amount of heat. Where mud bricks are still used, they continue to be in the same straw-and-mud composite form. This was probably contemporaneous with the development of pottery and no doubt a result of practical experiments with clay. Archaeological evidence suggests that people did try pure mud bricks, but these probably demonstrated their inferiority.
Composites likely continued to be construction mainstays in the ancient world with concrete probably being the most prominent example, at least to our eyes. The Romans were extraordinarily successful with concrete though they were not the first to get to this material. However, their particular recipe is widely recognised as being closest in terms of properties to what we use today. This extends to the use of the material to build jetties and other partially submerged structures — the Romans were the first to use a type of concrete (opus caementicium) that can be set underwater, a property we take for granted today. Some of their ruins are still with us today while structures such as the Pantheon in Rome continue to be public buildings alongside other major tourist attractions. We should note here that concrete also demonstrates that composite materials sometimes appear in nature as well, i.e. barnacles secrete a sort of organic concrete to bind themselves to substrates.
As time marched on, man-made composites proved themselves useful ubiquitously. Consider the famous composite bow of the Mongol mounted archer which played a pivotal role in creating the largest contiguous empire in the world. These bows consisted of layers of different materials such as wood, horn, silk, pine resin and sinew. The combination of materials allowed for composite bows to exhibit superior strength and performance compared with the simple purely wooden bows that had been the order of the day until that time. Intriguingly, this is probably the first time the word composite actually appears in descriptions of man-made things — concrete, for example, was not called a composite.
Mythology & Reality
On the subject of layers of material, we cannot ignore our favourite example — Homer’s description of Achilles’ shield from The Iliad. This was the flawed warrior’s second shield, with the first having fallen into the hands of the Trojan Hector. It is described in great detail, from both its creation to its use in battle (against Hector as it happens). Of course, Homer is no historian and Achilles’ shield was made by the Greek god Hephaestus, so this is mythology rather than science. However, Homer did not describe magical new materials (as Tolkien did with mithril) but actually layers of metal – external ones in hardened bronze, intermediate ones in tin and a central layer of gold. That might seem odd for a practical defensive construct, but Homer notes that spear tips that pierced the outer layers of the shield got stuck in the soft gold layer.
One might think that a storyteller such as Homer should not be a reference for historical information, but any fanciful leanings he might have had were based on some understanding of how real shields, or aspis as they were called, were made. Most aspis were made primarily of wood, with a bronze layer facing out and a leather one on the inside. There are accounts of such aspis featuring layers of metal as well, but none have survived. We know of their properties thanks to surviving artwork that depicts them and the works of a variety of writers who described them. There are some prominent examples of shield-like objects from antiquity that demonstrate that ancient humans knew how to work with composites, although there is considerable debate on the subject.
In the 19th century, with the scientific and industrial revolutions well under way, the specific properties of composite materials were better understood, leading to the development of polymer resins which were typically used as the glue to hold different materials together. Such resins remain in use today, in quartz kitchen countertops, for example. This was also the moment when scientists found a way to make synthetic sapphire crystal, via what is still known today as the Verneuil process. French chemist Auguste Verneuil came up with this technique in 1883 and the watch industry took notice. This was because the industry finally had an alternative to the natural rubies it was using in its mechanical movements as bearings to reduce friction. Friction is a long-standing villain in watchmaking, and movement jewels were the best work-around that watchmakers could come up with.
Let There Be Light
Returning to composites, the story of carbon fibre also began in the 19th century, but in a surprising way. The physicist and inventor Joseph Swan produced carbon fibres for use as filaments in light bulbs in 1860, but neither he nor Thomas Edison, who also did some pioneering work with carbon fibre for the same purpose, thought the material had any other applications. Nevertheless, the excitement over developments in the world of composite materials was palpable in the 20th century, although perhaps of a magnitude less than what was happening with plastics. Carbon composites never quite approached the cheapness of plastic nor of the synthetic resins that are a critical part of this story. There were however, of course, parallels.
In the early part of the century, Leo Hendrick Baekeland ushered in the era of contemporary composite materials when he developed Bakelite in 1907. Yes, this the very same brittle synthetic resin that would gain some notoriety on the bezel of the Rolex GMT-Master in the second half of the century (the material was even more brittle in 1907). Baekeland found he could soften and strengthen the synthetic resin by combining it with cellulose. Better and better resins continued to pop up, including polyester resin in the 1930s from American Cyanamid and DuPont.
At roughly the same time, the Owens-Illinois Glass Company developed what would become fiberglass, which is probably the most widely used composite material today aside from concrete and cement. That initial development saw glass drawn into thin strands or fibres, then woven into something like a textile fabric. When these glass fibres were combined with newer synthetic resins, the results were strong and lightweight composites. In the 1940s, fiberglass found its first applications in boating and would subsequently spread everywhere, given how cost-effective and useful it was. In watchmaking, that same cost-effectiveness probably limited its use, although we do know that Tissot was the first to use it in the Sideral watch.
Watchmaking brands with a passion for material innovation will never stop at just one type. Some brands offer bronze editions purely for aesthetic reasons and titanium ones with a functional rationale. For one particular set of very distinctive watchmakers, this is only the beginning. If you are Roger Dubuis or Richard Mille, what you want is something engineered for the extremes of outer space or the racetrack. Gregory Bruttin, Product Strategy Director of Roger Dubuis confessed to us that he is inspired by new technologies from outside traditional watchmaking; if you look at the brand’s watches, this is hardly newsworthy.
In this rarefied segment, contemporary art also enters the picture, which brings us to Roger Dubuis watches such as the Excalibur Twofold. We initially pursued the Roger Dubuis manufacture to find out if the ultra-white Twofold — it reminds us of bone china or perhaps Meissen china — was some type of advanced ceramic. Instead, it turned out to be a composite, as if the name Twofold was not an indicator. The case, crown and bezel are crafted in Mineral Composite Fiber (MCF), a term new to us; nevertheless, the word “composite” drew our attention. The facts are different to perception though, and the manufacture told us that this new material is 99.95 percent silica. As we suspected, this is entirely new in watchmaking and was a first at its world-premiere in 2020. You might wonder about the art angle here; the answer can only be found in the movement in the dark as parts and even the strap glow. This was the first time – to our knowledge – where strap, dial elements (some of which are also in MCF) and movement all glow in the dark.
While we have looked elsewhere at Panerai for Carbotech, it is worth noting that it too has plenty of material experiments ongoing. Consider the examples of the Luminor Marina Fibratech (PAM1663), Luminor Marina DMLS (PAM1662), Luminor Marina Fibratech (PAM1119) and a couple of other BMG (bulk metallic glass) models we want to get our hands on.
For the purposes of this brief note though, the watch we are looking at here is the PAM1119, cased in a brand new material combining basalt with other minerals. These minerals are worked as fibres, then layered according to orientation and combined together via a heat and pressure process. The case is built up in layers, just like the Carbotech material; indeed the description is the same, except here we have basalt and other minerals rather than just carbon.
Bound for Space
Composite materials made a name for themselves in aviation, motoring and construction, with carbon fibre itself being patented in 1961. Oddly enough, there are no firm records on when the first carbon fibre watch case was introduced but it seems likely that this was in the 1990s with Audemars Piguet leading the way. As far as forged carbon is concerned — also a composite — it is certain that Audemars Piguet did it first in 2007 with the Royal Oak Offshore Alinghi Team watch. By the 1970s, the automotive industry was the biggest user of composite materials (again, excluding concrete and cement) and it remains that way today. By way of contrast, composite materials have not taken root in the same way in traditional watchmaking.
The rise of 3D printing in the 2010s brought manufacturing into homes and small businesses, allowing users to bring to life from a desktop any item they can dream up with a CAD program. Composites companies are jumping into the field by 3D printing items with reinforced fibres. Discontinuous strands of carbon fibre or fiberglass are most frequently used to reinforce plastics in 3D printing processes across every market sector, including automotive, aerospace, tooling, medicine and infrastructure. These reinforcements deliver the strength of composites with less material in less time and can be designed and prototyped from a single desktop. In 2014, MarkForged announced the world’s first carbon fibre 3D printer.
The above is a very truncated version of the story of composite materials in the world. Just looking at the rapid pace of development in the area of carbon composites is worth a separate article. On that note about carbon fibre 3D printing, SpaceX commissioned and built a massive fuel tank for its proposed Mars mission entirely with 3D printers. This 14 metre tall and 12 metre wide tank was tested to great acclaim in 2016, but SpaceX has since demonstrated ongoing issues with its carbon composite tanks. This is not to cast shade on the firm or the technology, but merely to illustrate that applications for carbon composite structures are on the very edge of what is possible. (Head over here for Part 3 of the story).
This article was first published on Issue #69 of World of Watches.
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