YouTube
Instagram
Facebook
TikTok
Good evening everyone!
This column talks about mechanical watches from an engineer's point of view. This is the 12th installment.
"About watch crystals: their respective characteristics"
I will talk about this topic.
The crystal of a watch (windshield) is literally a part designed to prevent the harmful effects of wind, and is an important part that protects the dial.
And the glass mainly used in watches is
"Plastic (acrylic resin)"
"Mineral glass"
"Sapphire crystal"
There are three types as above.
This time we will explain the differences between these types of glass, so please read to the end.
"Plastic windshield"
Plastic windshields are made of "plastic (acrylic resin)" and are sometimes called plexiglass. It is the lightest and softest of the three materials, and its greatest feature is that it is easy to process.
Plastic crystals were mainly used in watches from the 1940s to 1970s. They are still used today in reissue models and the Omega Speedmaster, but they are still generally associated with vintage watches.
In addition, the plastic crystals used in watches are often domed, which gives them a completely different feel from sapphire crystal glass, which is generally flat, and creates a warmer design.
The reason why plastic windshields are dome-shaped is to increase their strength. Unlike glass, plastic windshields are weak to impacts and tend to break easily. Therefore, by giving the shape a curve, the tendency to break is reduced.
However, because the crystal is raised, it is easy to get scratches without realizing it, and because the material is soft, you need to be careful about scratches. For this reason, it can be said that this material is particularly suitable for those who enjoy small scratches and the aging of the watch as a unique feature.
Another advantage of plastic crystals is that even if they get scratched, they can be polished off. This is something that cannot be done with sapphire crystal or mineral glass, so you can ask a watch repair shop to polish it for you, or it is not that difficult to polish it yourself using a polishing agent for plastic.
By the way, if you want to remove scratches from sapphire crystal or mineral glass, it is difficult to polish them, so you will have to replace the glass, which will be very expensive.
Mineral glass
Mineral glass refers to ordinary glass, and is a material that is widely used for everyday items such as window glass and cups. It is characterized by its slight color compared to the colorless and transparent sapphire crystal.
Mineral glass is harder than plastic, but not as hard as sapphire crystal, with a Mohs hardness rating of at most 6, and at most 3. ( Mohs hardness is a measure of the hardness of minerals, expressed as an integer value from 1 (soft) to 10 (hard). )
Therefore, it has the disadvantage of being easily broken and chipped, but because it is a low-cost and easy-to-process material, it is also the material used in many watches.
Mineral glass is mainly used in casual watches priced under 50,000 yen, and it does not seem to be used much in luxury watches.
This was used in some Tudor models in the 1990s, but when the glass needs to be replaced during maintenance at the manufacturer, it is switched to sapphire crystal.
Sapphire crystal
Sapphire crystal glass is the type of glass most commonly used in luxury watches, and is as hard as the natural gemstone sapphire, making it extremely scratch-resistant.
It is a material that has the highest rating of "9" on the Mohs hardness scale, so it will not be scratched by a light rub, and it will not be scratched easily even if it is rubbed with a hard metal. It is a very popular glass because it can keep its shine forever.
However, its excellent properties also mean that it is expensive, and although it is an ideal material for watch glass, it is only used in luxury watches.
It does not get scratched like plastic, and is not as fragile as mineral glass. And yet, due to its high purity, it boasts excellent visibility, and is not only highly practical, but also has a beautiful appearance as glass, so it has quickly become a major choice for the crystal of luxury watches.
Due to its hardness, it is difficult to process, but there are brands such as Hublot that are using sapphire crystal for their cases, and unusual varieties such as the green sapphire crystal used in the Rolex Milgauss, so it is a material that is sure to become popular in the future.
summary
What did you think?
There are three types of glass available: plastic (acrylic resin), mineral glass, and sapphire crystal, each of which has its own attractive features.
Just as you choose a watch based on its design and functionality, such as sapphire crystal for durability or plastic for a retro feel, it might be interesting to choose a watch based on its crystal.
We hope that this article has been useful to you and has piqued your interest in luxury watches! If you have any questions, please feel free to contact us directly and we will answer them thoroughly. We look forward to your visit and inquiries.
Look forward to the next one! See you next time!
