Ocean Ready: The Tudor Black Bay 58 Bronze

I would say “everybody loves patina” but like any other blanket statement, this one has to come with some qualifications. Let’s start out talking case metals. For most of the history of watchmaking, you had basically one choice and that was gold (and, once we worked out the technical kinks involved in refining it, that is; jewelers started to use platinum in the early 19th century, and it didn’t really start to take off until the 1800s were winding down). Gold isn’t a perfect metal for watch cases – for one thing, it’s pretty soft and you have to alloy it to 18K or 14K for it to be usable – but what it does have going for it, is resistance to corrosion.

Corrosion Vs. Patina

So what don’t you want for a watch case? You don’t want a metal that’s going to corrode, which is why if you look back at the history of watchmaking, metals like silver and bronze are mostly notable for their absence. The formation of a surface layer of oxidation on a pocket watch is more a cosmetic nuisance than anything else, since pocket watches live in pockets, but for a wristwatch, where the case metal is in constant contact with skin, sweat, skin oils and salts, oxidation and corrosion becomes a practical problem very quickly.

With this in mind, it’s interesting to consider the fact that bronze historically has been extensively used exactly where you wouldn’t think it would be suitable at all, which is in the ocean. Bronze alloys which have been formulated for immersion in seawater have been, and are still being used, for fasteners, ship’s propellers, standard dive dress fittings and more, and even up on dry land, bronze statuary can last in the outdoors for centuries. The chlorides in seawater, don’t get me wrong, will eventually eat through bronze and destroy it completely, but marine bronzes, which are usually alloyed with aluminum, are much more resistant to corrosion than conventional bronze alloys. Like other bronze alloys, marine bronzes rapidly develop a surface layer of patina consisting of copper and aluminum oxide, which resists any further corrosion.

The process of formation of a surface oxide layer that protects the bulk metal from further oxidation is called “passivation” and it’s the reason that metals which oxidize rapidly, like aluminum, are usually thought of as highly corrosion resistant. The stable patina you get on bronze is a passivation layer – technically, it’s corrosion since corrosion broadly defined is the formation of metal oxides, but I draw the distinction just to point out that we usually think of progressive destruction of the bulk metal when we use the word “corrosion” whereas a patina actually acts to preserve the underlying metal.

Patina And The Black Bay 58 Bronze

This brings us by a somewhat long and winding road to the Tudor Black Bay 58 Bronze. Tudor has produced a couple of versions of the Black Bay in unusual metals and this is one of them (the other is sterling silver; the silver alloy that Tudor uses in the Black Bay 58 925 is also formulated to resist tarnishing).

The first Black Bay Bronze watch, 43mm in diameter and a mainstay of the current catalog, was released at Baselworld in 2016 and the Black Bay 58 Bronze debuted a few years later, in 2021. The original Black Bay Bronze is available either with a black leather or pass-through fabric strap; the BB 58 Bronze, on the other hand, comes on a riveted bronze bracelet and also comes with a pass-through fabric strap as well.

Bronze for wristwatch cases is a fairly recent development – the first time anyone used bronze in a watch case, was in the 1980s when Gérald Genta used it in the Gefica Safari. (The Gefica was re-released by Bulgari as a Bi-Retro model after Gérald Genta was acquired by Bulgari in 2000; we took a look at one in May of last year for A Watch A Week). Since then, bronze has been used by a number of different brands in different alloy formulations, some more resistant to corrosion than others. The amount of patina that develops is pretty variable from watch model to watch model and brand to brand, thanks to the variations in bronze alloys used in different cases, and, even more, thanks to variations in how often and where the watch is worn,  and if you go hunting around for images of patina on bronze cased watches, you can see everything from tastefully even darkening with a steely-eyed mariner vibe, to some fairly hairy looking heavy greenish oxide accumulation which looks a little too reminiscent of bread left out on the counter for a few days for its own good.

With the Black Bay Bronze and BB 58 Bronze watches, however, you are pretty much guaranteed to get the former rather than the latter. The aluminum bronze used in Tudor’s bronze watches is here for both a good time and a long time – you’ll eventually get a patina, of course, but the passivation layer formed is quite hard and while it will darken over time, it will also act as a preservative for the case overall. The same goes for the bracelet. The major caveat, I would think, would be salt water immersion on a regular basis – if you’re swimming or diving in the ocean with the BB 58 Bronze (or for that matter any bronze watch) taking a minute to rinse the watch off in fresh water afterwards is probably not a bad idea. It’s not a bad idea for stainless steel watches either, honestly. Stainless steel is corrosion resistant but it also relies on a surface passivation layer formed from the chromium in stainless steel alloys and if pitting starts to form on the surface, corrosion can eventually eat right through the case.

Bronze Patina: A Record Of Time

The thing about bronze patina is that, like the patina found on the dials, hands, and lume of vintage watches, it’s a visible reminder of the passage of time, and therein lies the charm of a bronze watch. In discussions of bronze watches you often hear folks wondering what you can do to prevent, or at least to slow, the formation of patina on bronze watches but of course, the formation of patina and the changing appearance of the watch over time is the whole point of owning a bronze watch to begin with. If you’re c0nsidering a bronze watch, the formation of patina and its gradually changing appearance over time – the darkening colors, the way the depth and density of the patina changes over the surface of the watch and the way the variations in patina emphasize the shape and physical dimensions of the case – is something you want; it’s an experience you want to have and to enjoy, and you’re looking forward to it going in.

One particularly interesting feature of the Black Bay 58 Bronze (and its slightly bigger brother) is the contrast between the case patina and the finishes on the dial, dial markers, and bezel. The crisply delineated dial and bezel stand out sharply against the case patina as it develops, giving depth to the visual experience and also emphasizing, by contrast, the process of patination and passivation going on with the case. The gilt accents on the dial and bezel act as a kind of visual bridge with the case itself, keeping the design integrated.

The movement’s Tudor’s COSC chronometer certified MT5400, with freesprung balance, silicon balance spring, and 70 hour power reserve – a very modern movement for a watch with an almost archaic appeal. If you like the tangible presence of history, and deep history at that, in your watches, the Black Bay 58 Bronze has a lot of very old school charm. Bronze is an ancient metal; it’s the alloy that really lifted us out of the Stone Age and it was already old when the Greeks and Trojans used it for their spears, swords, and armor (Homer gave it the epithet, “pitiless bronze”). A watch marks the passage of time but few do it in such a complete fashion as a bronze cased watch, where the patina forms a visual – and chemical – kinship with a tradition going back five thousand years and more.

See It Here