Today, we’re launching the first of a three-part series on bronze watches by contributing writer Justin Mastine-Frost. This weekly column will address the various aspects of owning and caring for a bronze watch that extends beyond the obvious passion for patina. Topics covered will include the pros and cons of aging the material naturally versus with chemicals and what you need to successfully clean the metal. First up? A look at why bronze has risen to such immense popularity over the past decade and what you should look for when you’re thinking about purchasing your first bronze watch.
There’s no arguing that there has been an unrivaled boom of bronze in recent years – ushering in what one could only call a new “Bronze Age” in watchmaking. In part fueled by a growing love of unique and individualized timepieces, and in part by the enthusiast community on Instagram, bronze has rapidly become the new “it” metal – especially in the more approachable end of the luxury watch industry. The metal’s transformative properties run contrary to anything else in the market, having the ability to age over time, and depending on the alloy composition, the end result can vary significantly from one watch model to the next. While some will want to maintain that crisp bright bronze color as factory-fresh as possible, others are quick to find ways to force the aging process, giving their bronze watches the appearance of having spent years on the ocean floor. Much as we’ve talked about many of the beautiful bronze beasts to hit the market in recent years, we’ve yet to delve into what is really entailed when it comes to the day-to-day life of bronze watch ownership.
A Sea of Options
With the ongoing growth in the category, watch enthusiasts are anything but short on options for bronze watches. Initially, a category reserved for dive watches, the past year has seen bronze (or bronze and steel) offerings surface from Montblanc in the form of the 1858 Automatic, 1858 Automatic Geosphere, and 1858 Chronograph Tachymeter Limited Edition that are anything but dive-ready tool watches. These dressier offerings were a welcome change of pace, especially in the case of the Chronograph Tachymeter – the beloved monopusher chrono powered by Montblanc’s hand-wound Minerva Manufacture Calibre MB M16.29.
When it comes to bronze divers, the category also continues to grow. After the immense success of the Oris Carl Brashear diver, whose limited production run of only 2,000 pieces sold out well before the year came to a close, Oris unveiled its successor in the form of a diver chronograph this past January worthy of equal levels of praise. Only slightly larger in diameter than its sibling (43 mm instead of 42 mm for the three-hand version), it features the same vintage-style domed sapphire crystal, as well as a handsome one-piece rotating bezel that uses a mix of engraved and relief indexes.
On the more obscure end of the spectrum, Mühle Glashütte also opted for bronze to commemorate the 15th anniversary of the brand’s SAR Rescue Timer in 2017. Fitted with a fully luminous dial, and contrasted by its trademark rubberized bezel and a DLC-coated crown, the new model is offered on an olive drab Bund strap and has been limited to a very scarce 150 pieces worldwide.
Of course, the big news in the category that ruffled a fair number of feathers in the collecting community was the arrival of another Bronzo from Panerai in the form of the PAM 671 Luminor Submersible 1950 3 Days Automatic Bronzo. Panerai’s original Bronzo (the PAM 382) from 2011 and the PAM 507 that followed in 2013 have long been two of most sought-after modern Panerais on the planet, and many Paneristi were once again furious with the brand for launching a third version, thus (in their eyes) making the originals less collectible in the long run. Coming at it from the industry side of the table, in a market as challenging as all the luxury brands have had to navigate in recent years, and considering the success of the first examples, launching the PAM 671 was simply a no-brainer, and being a limited edition model (1,000 pieces), shouldn’t have a truly catastrophic impact on overall collectability.
A Tale of Alloys –
Where Percentages Make All the Difference
While it’s easier to say that “bronze is bronze” in some respects, a quick glance at the wide variety of bronze watches on the market will quickly reveal some significant variance from one model to the next. More often than not, watchmakers are using what is referred to as an aluminum bronze alloy. Now bronze on its own is primarily made of copper, and a wide variety of other metals can be folded into the equation in varying percentages. In most cases, the ingredient added is tin, but arsenic, phosphorus, aluminum, manganese, and silicon can also be used to produce different properties in the material.
In the case of watchmaking, where corrosion and deterioration are concerns, aluminum bronze is most often the weapon of choice, though even within this specific alloy we see some variance. A maximum of 6 percent iron and 6 percent nickel are permitted, however the percentage of aluminum can vary, somewhere in the spectrum of 6-12 percent. Generally speaking, a higher aluminum content presents a slightly cooler gray hue in the bronze whereas a lower percentage allows the warm copper tones to become more prevalent. Looking at the latest swath of releases, we can easily speculate that the Tudor Black Bay Bronze carries a higher percentage of aluminum and other metals, whereas the Oris Carl Brashear Chronograph would be on the lower end of the spectrum. That said, no watch brands at this stage have been willing to release data on what their ideal bronze formula actually is.
As many may have noticed, effectively every bronze watch on the market uses a caseback made of either stainless steel, titanium, or in some cases, an exhibition caseback. The need for this is twofold. The copper in the alloy has a tendency to react to the moisture in human skin, creating that green substance on the surface of the metal (copper chloride) and turning both the metal and your skin green. Not only is this less than pleasant from a visual perspective, but prolonged exposure to copper chloride generally isn’t good for your health and is better off avoided when possible.
All text by Justin Mastine-Frost.
You can read Part 2 on how to chemically age your bronze watch here.
You can read Part 3 on how to clean your bronze watch here.