What is Flame Blue Hands and Screws?
A Cerulean as Profound as the Ocean
Flame Blue Steel: The Beauty of Craftsmanship in Classical Watches
Flame blue is a classical technique in traditional watchmaking of handling steel hands and screws.
As early as the 16th century, craftsmen employ the technique heating the steel watch hands and screws to form an oxidized protective layer. This thin layer of oxidation provides the steel surface with a certain degree of corrosion resistance. As an added benefit, when the hands and screws reach a certain temperature, they become tempered, i.e. less brittle and more ductile, while giving a marvelous deep cerulean blue. This, is flame blue.
Capture the Ephemeral
This particular blue is so captivating due to the special science behind the color. For ordinary objects, they show color because, like ink, they contain tiny colored particles called pigment, which reflects light of that particular color. Therefore, the color reflected is solid and opaque. In contrast, the oxidation layer which gives it the color blue is actually colorless. It creates color through a physical phenomenon known as “iridescence”, which is also why peacocks look so colorful.
If you have a chance to witness how a silver steel hand is heated to flame blue, you will first see it change from gold to brown and then purple before it settles to flame blue. If it is heated further, the steel hand turns light blue and eventually light gray. The entire process takes only a dozen of seconds, while the most mesmerizing shade of flame blue flashes by in a split second. Even heating it a second more or less would mean an entirely different color. This is iridescence in action: heating creates a very thin layer of oxidation on the surface of steel, and this colorless layer changes the angle of light reflected, which then interferes with the light reflected from the steel surface to produce colors. Thus a change in the thickness of the oxidized layer changes also the angle of reflection, thus changing the color it finally produces. So, as heating continues, the oxidation layer accumulates and gradually thickens, varying the angle of reflection, and you can see the changing color.
Difference of seconds would result in an entirely different color
This explains the uniqueness of flame blue: the blue you see does not really “exist”. The blue is formed by how the reflection of a thin, almost-transparent film changes reflected light. That’s why when you look closely at a set of flame blue hands, you can observe a special depth in the blue, as if you are looking through a transparent window, and beyond the window is an ocean of blue. This is the charisma of flame blue.
Flame Blue Steel Nowadays
Today, technology for corrosion resistance is far more advanced than it was in the 16th century. The complex procedures of making flame blue steel, as well as the demanding requirements of the craftsmen’s sensitivity to minute differences in color make hand-made flame blue hands an exceedingly expensive process. Therefore, watches today rely on other methods to provide corrosion resistance. As for the blue color, it is achieved usually through electroplating or spray-painting instead.
That’s why now only high-end brands still insist on using manual flame bluing on every hand and screw, and it becomes a much sought-after feature in luxury watches. In EONIQ workshop, you can try to flame blue a set of watch hands in the traditional way, which will then be installed into your own EONIQ watch, creating a watch that is unique to you.
If you like flame blue,
you might appreciate the arts of our workshop participants.
Flame Blue Watch Hand Workshop
Come join our workshop at our flagship store @The Mills in Tsuen Wan! Here you may flame blue a set of flame blue hands in the traditional manner, and adorn your own EONIQ watch with your own flame blue hands. Or combine this with other workshops, and create a watch with more components unique to YOU.
Here’s what you’ll get to experience:
Manual flame bluing requires a high degree of focus
Our craftsman will show you how to heat up the watch hand
We will provide you with some practice watch hands so that you can familiarize yourself with the time it takes to heat up the watch hand
After practice, we will provide you with a new set of watch hands for you to flame blue\
Our craftsman will install your flame blue watch hands in your watch.
Flame Blue Screw
Our Signature Workshop allows you to work on hand-made flame blue screws in the movement and leave marks of your crafts on your movement. Please check out the details in the Signature Workshop page.