Watch glasses have to be robust against scratching and rupture.
Scratch resistance is measured on the Mohs hardness scale in steps of 1-10. The following types of glass are used with watches
- Plexi / acrylic glass
(polymethyl methacrylate (PMMA)); 3-4 Mohs, little scratch resistance, but unbreakable. Scratches can be polished with special acrylic polishing paste. From this material extremely arched (domed) watch glasses can be produced.
- Mineral glass
5 Mohs. Mineral with hardened surface 6-7 Mohs (harder than stainless steel).
- Sapphire crystal
is an artificially produced crystal 9 Mohs (close to diamond, extremely scratch resistant and break-resistant).
watch_glass.txt · Last modified: 03.07.2022 15:39 by 127.0.0.1