Guides Watches

8 Watch Case Materials You Should Know About

Audemars Piguet Royal Oak Perpetual Calendar Blue Ceramic

In recent years we have seen a growing trend towards new watch case materials beyond the usual steel and gold. Stainless steel might still be the most popular however, watch cases have seen large innovation with the use of alternative materials becoming more commonplace. Look at many recent new releases and there’s a high chance you’ll find a model variant made from titanium, ceramic, bronze, sapphire or another innovative material.

This growth is in part due to two primary factors. The first is the push by the industry to innovate and create new and exciting products. Brands can often face a backlash if their new releases don’t hit the mark or seem too boring. A 1mm change in case size just won’t cut it with the watch community these days. Instead watch enthusiasts want to see changes and updates that they can get excited about, and crafting a watch out of a material other than steel or gold is a great way to grab attention. Secondly, the advancements in material science over the last 20 years have now made the possibilities for differing case materials infinitely more possible. And cheaper!

Stainless steel has been a mainstay of the watch world since the 1970’s. The main reasons for its longevity as a brand favourite are its hardness and resistance to corrosion. Unlike many metals it doesn’t rust, corrode or oxidise meaning it won’t discolour over time. Rolex in particular takes the anti corrosion aspect of steel very seriously. Rolex steel watches are made from 904L stainless steel, where most other brands use 316L stainless steel. So what’s the difference? In short, 905L contains additional amounts of Nickel and Copper. It’s the copper in particular which adds an additional level of corrosion resistance.

Piaget Polo 79

Piaget Polo 79

Stainless steel hasn’t always been the favourite of the watch industry. Because of its hardness it is incredibly difficult to mould and shape. Therefore, softer materials like gold were preferred until the introduction of high powered machines made steel easier to work with. To put this into perspective 18 carat gold has a rating of around 2.8 on the MOHS hardness scale whereas steel has a rating of 6. Despite the benefit of steel, gold is still a frequently used material due to its precious metals status. Let’s not forget gold is a traded commodity so has more value, (hence the price tag). It also comes with status and a considerable amount of weight at more than double the density of steel.

For decades steel and gold have been the poster children of watch materials, but now there are some new kids on the block hoping to attract your attention. Let’s take a look at some of the most popular new watch case materials.

Platinum

A. Lange & Sohne Lange 1 Perpetual Calendar Platinum

A. Lange & Söhne Lange 1 Perpetual Calendar

Platinum is often seen as the pinnacle of watch making. If gold is a step above steel then platinum is a level above gold. This is best highlighted by Rolex who reserves platinum for the heroes of their catalogue in the Platinum Day Date and Platinum Daytona. In order to signify their superiority Rolex platinum references are offered with an ice blue dial. A dial colour that Rolex doesn’t offer in any other watch.

Platinum is regarded as one of the most precious metals on earth, it is rarer and usually more expensive than gold. It’s also considerably heavier with the added weight giving it a more premium feel. As a precious metal it’s not as hard as steel so it can scratch and dent. It’s why it’s rarely used in sports watches and instead reserved for dressier watches.

One of the best examples of this is the A. Lange & Söhne Lange 1 Perpetual Calendar. The 42mm platinum case version on a black leather strap representing one of the most sophisticated perpetual calendar watches available. Platinum has a couple of other benefits up its sleeve. As a naturally occurring white metal it won’t tarnish, unlike white gold which will need polishing from time to time to return it to its original shine. It’s also slightly harder than gold making it marginally more scratch resistant.

Sterling Silver

Tudor Black Bay Fifty Eight 925

Tudor Black Bay Fifty Eight 925

Keeping with the theme of precious metal, sterling silver isn’t a material you see very often in watch making. Yet, it is a mainstay of the jewellery scene. This is mainly because of its softness and high level of oxidation. In levels of tensile strength silver sits just below gold and someway off the strength of steel. Even in the early days of watchmaking when softer metals were preferred due to their malleability, gold was always the preference over silver. In today’s modern world where we are turning towards harder and stronger materials such as carbon and ceramic, it’s hard to see where silver would find its place.

One of the drawbacks of silver can also be one its advantages. High levels of oxidation. Oxidation will tarnish a watch over time and cause it to change colour as the silver reacts with oxygen in the atmosphere. With silver this tarnish tends to take on a yellow-ish tinge. This natural tarnish, or patina, is liked by many as it gives the watch character and makes it unique. The counter argument to this is why would you want a watch to turn yellow when it’s a beautiful shiny silver colour? It’s really a personal preference.

One of the benefits of silver over steel is its shine. When new, silver watches are brighter than steel and in contrast can make steel look like a duller metal. This is the main reason sterling silver is used more in jewellery. Brands like Tudor have made attempts to try and harness the benefits of silver and negate some of the drawbacks. In the Black Bay Fifty Eight 925 Tudor created a sterling silver watch made from their own silver alloy. This alloy was designed to hold the colour of silver longer and tarnish less compared to pure silver.

Bronze

Oris Divers Sixty-Five ‘Cotton Candy’ collection

Oris Divers Sixty-Five ‘Cotton Candy’ collection

From one oxidising metal to another. Bronze shares the same tarnishing and chameleon colour changing ability as silver. The difference with bronze is that the colour takes on more of a rustic gold type appearance which many feel is more pleasing on the eye. With all watches that tarnish you never know what you’re going to get. Every watch reacts differently and the amount of wear, sunlight and water exposure will all affect the overall appearance. On the one hand this might stop you getting bored with a watch as it patinas and takes on a new look. On the other hand you need to be aware that the new watch you just bought won’t stay looking that way unless you’re prepared to polish it regularly.

Bronze is an alloy made predominantly from copper and tin with the likes of zinc, aluminium and other metals added to help improve its characteristics. In the past bronze has been the metal of choice in nautical equipment and anything based near water due to its high levels of corrosion resistance.

Oris Divers Sixty-Five Date Cotton Candy Sepia

The big drawback for bronze is that it doesn’t react well with your skin. In most instances bronze watches will use steel or another material for the case back so that bronze isn’t in direct contact with the skin. Even the Oris Divers Sixty Five Cotton Candy, an entirely bronze watch, comes with a stainless steel case back. If bronze does come in to direct contact you’ll often find green marks appearing on your wrist. This is caused by the copper reacting with the chemicals in your skin and sweat.

Titanium

Rolex Oyster Perpetual Yacht-Master 42 RLX Titanium Ref. 226627

Rolex Yacht-Master 42 RLX Titanium

The first thing you will notice with Titanium is that it is light. When you first pick up a titanium watch the weight can be quite alarming. It feels like they forgot to put the movement in. In fact titanium is about half the density of steel so you can expect it to weigh up to 50% less. For comparison the Rolex Yacht Master RLX Titanium weighs in at just 100g whereas the stainless steel Rolex Submariner tips the scales at 160g. Don’t forget the Submariner is also 1mm smaller in diameter. Unlike our silver and bronze watches titanium doesn’t tarnish and is also highly resistant to corrosion. Corrosion isn’t something you face very often with a watch but it’s good to know that if you dunk your titanium watch into salt water on a regular basis it won’t suffer any ill effects.

In watch making there are typically two different types of titanium which are most commonly used, Grade 2 and Grade 5 titanium. Grade 2, considered pure titanium, is a softer element which makes it difficult to create a variety of finishing options. When using steel a watchmaker has many options to choose from when they finish a watch. They can create a high polished finish, a brushed, satin or even matte look depending on how the steel is manufactured. With titanium the best way to achieve these different levels of finish is to use Grade 5 which thanks to the inclusion of aluminium and vanadium is significantly stronger. This grade of titanium is therefore better suited to polishing and finishing, however due to the complexity of manufacturing Grade 5 watches are often more expensive.

Sapphire

Hublot Big Bang Unico Sapphire 42

Hublot Big Bang Unico Sapphire 42

Sapphire in watches isn’t a new thing. Sapphire crystal has been used consistently since the 1970s as the transparent scratch resistant dome over the watch face. The ability to machine a circular piece of sapphire to create the window for reading the dial has been well and truly mastered. However, using sapphire to craft an entire watch case is a different story.

The biggest challenge with sapphire cases is that they need to be made from a single piece of sapphire. Creating the synthetic sapphire requires heating aluminium oxide to extreme temperatures until you are left with a transparent block of sapphire crystal. From this block your watch case needs to be shaped. What makes working with sapphire so difficult is the hardness. On the MOHS hardness scale Sapphire sits just behind diamond at the top of the class. The benefit of sapphire then is that diamond is about the only material that is hard enough to scratch it.

This great benefit comes at cost. That large block of sapphire that needs shaping into a watch case is so hard that try to cut or drill it with metal machinery you won’t get very far. Instead a set of very expensive and specialist diamond tipped machines are required. This challenge is what makes watches like the Hublot Big Bang Unico Sapphire so impressive. These sapphire cased watches are incredibly difficult and time consuming to make but the outcome is a show stopping masterpiece of material science with a price tag to match.

Ceramic

Omega Seamaster Diver 300m Co‑Axial Master Chronometer 42mm 'Summer Blue' 75th Anniversary

Omega Seamaster Diver 300m ‘Summer Blue’ 75th Anniversary

Ceramic is a material significantly on the rise and not one associated with watch making until 1984 when IWC introduced a ceramic version of their Da Vinci model. You’d be forgiven for thinking ceramic is a material better suited to kitchenware and decorative vases and therefore a terrible material for a watch. However, ceramic describes an in-organic, non metal material created through extreme heat. Because of this broad definition everything from diamond to glass and even sapphire can be classed as a ceramic.

In the instance of ceramic watch cases the material usually starts life as an oxygen or carbon based compound. The most common is zirconium oxide. Look closely and you’ll see the text ‘ZrO2’ on the dial of the Omega Seamaster Diver 300. This ceramic compound in powder form is subjected to huge amounts of pressure and heat until it creates a solid, extremely strong and scratch resistant material.

IWC Big Pilot’s Watch Chronograph Top Gun Editions (Lake Tahoe and Woodland)

IWC Big Pilot Top Gun Woodland and Lake Tahoe

These key features are some of the main reasons ceramic has been a material on the rise. Compared to steel, ceramic is typically 4 times harder. In practice this means your watch will maintain its showroom look without collecting any hairline scratches. The hardness of ceramic means, as with Sapphire, it’s time to break out those specialist diamond tipped tools once again. The other main benefit of ceramic over metal compounds is the ability to create colours. Whilst gold gives you white, yellow and rose options with ceramic you can pretty much have any colour you want. The IWC Lake Tahoe, for example, has a white case – a colour that could only be achieved with ceramic.

This all sounds very idyllic so far, unfortunately ceramic has a couple of drawbacks that stop it being the material of choice among watch brands. As you can probably guess, ceramic is very difficult to make and to work with. There are several reports of brands suffering very high failure rates when working with ceramic, which means several attempts to make your watch end up in the bin. Secondly, whilst ceramic is extremely hard it’s not very tough and this can be a problem. Drop it or hit it hard enough and it can fracture or shatter and putting it back together again isn’t an option.

Carbon Fibre

Girard-Perregaux Laureato Absolute Chronograph Aston Martin F1 Edition

Girard-Perregaux Laureato Absolute Chronograph Aston Martin F1 Edition

Carbon fibre is a material that can be found in many industries usually at the cutting edge of performance. It’s used heavily in Formula 1 cars, is a popular material for the latest and greatest in golf club technology and is even used in aeroplanes for wings and other key components. Carbon fibre typically comes in two forms. Sheet carbon and forged carbon. Sheet carbon is created from strands of carbon that are woven together. As the name suggests sheet carbon isn’t particularly thick and therefore often used for the bodywork on Formula 1 cars. Sheet carbon has a very uniform appearance; you can see the pattern where the carbon strands have been woven together.

Forged carbon is a little easier and quicker to make. Forged carbon is a composite that blends a liquid plastic resin with carbon fibre strands. The resin and carbon fibre when mixed can be shaped or poured into moulds. Simply add some heat and pressure and you end up with a solid piece of forged carbon. This type of carbon gives a milky swirl type look to the material. Due to the mixing of the carbon fibres and epoxy resin the appearance of two pieces of forged carbon are never identical. To honour their partnership with Aston Martin F1 it was only fitting that the Girard Perregaux Laureato Chronograph Aston Martin was made with a carbon fibre case. The pattern of the case looks random and was made by mixing carbon fibres with a resin, much like a forged carbon.

Whichever type of carbon process is used both maintain the same basic benefits. The reason carbon is used in motorsport and aerospace engineering is because it is both incredibly lightweight and strong. In some cases carbon fibre can be up to 5 times stronger than steel. Place it on the scales and it comes in up to 75% lighter than steel. It’s even lighter than the lightest metal on this list, titanium.

Quartz TPT

Richard Mille RM 35-03 Automatic Rafael Nadal Blue Quartz

Richard Mille RM 35-03 Rafael Nadal in blue quartz TPT

Quartz TPT is a material almost exclusively associated with Richard Mille. The brand has heavily lent in to the material for many of their watches since its debut in 2017. This is thanks to a partnership with a company called NTPT who exclusively provide the material to Richard Mille. TPT stands for ‘thin ply technology’ and involves layering lots of thin sheets of dry fibres on top of each other and then injecting with a resin to create a solid material. The direction in which you lay the dry fibres helps denote the final pattern of the material.

Initially this process was an advancement of carbon fibre whereby the dry material used strands of carbon. Due to the colour of carbon this made making TPT cases in anything other than black very difficult. Instead the technology advanced to experiment with quartz fibres which have a more translucent colour. This means if you add colour to the resin you can now change the colour of the final material.

Quartz TPT, much like carbon fibre, is incredibly strong thanks to the approximate 600 layers of fibres that are required to create a watch case. Add to this the now endless possibilities of colour as with the blue Richard Mille RM35-03 Rafa Nadal and Quartz TPT has a one up on carbon fibre. At the moment though, you’ll need to buy a Richard Mille if you want any Quartz TPT on your wrist.

Leave a Comment

*

*

About the author

James Lamburn

James' love affair with watches started when his grandad left him a two tone Tissot. From that moment he was hooked and he’s been daydreaming about watches ever since. Over the years his passion for watches has expanded beyond collecting and dinner party conversation. James now operates as a freelance writer covering all things watches and horology.