71 | Glass Manufacturing Methods, Molding Methods, and Processing Methods 9

Hello everyone! 🎵 We've had continuous scorching hot days, but at night I've started hearing insects chirping, and the wind seems to have eased a bit from its murderous heat. The long-term forecast says it will be hot until November, so please make sure to take care of your health by staying hydrated, nourished, and getting enough sleep.

Last week, during the melting process, I talked about the "Neko Kama" (cat kiln), and I received some lovely messages saying it was cute and that people wanted to see the actual thing. Thank you!

A handmade glass factory is, in a way, a very dangerous place where glass material melted at 1400°C is shaped. It's a battlefield where craftsmen, trained by skilled seniors, work with the utmost care and the best techniques. We generally don't have facilities or safety measures to guide general customers, so opportunities to see the actual factory are rare. We'd be delighted if you could watch it on YouTube, etc.

https://www.youtube.com/watch?v=QGUVkUD1aXI&list=PLpfjdFFCDh8z3JXtbuNu3wyRhFFIFX6lQ&index=3

In automated production for mass quantities, the melting is done in a "tank furnace" rather than a "crucible furnace." In a large, pool-like area, raw materials are introduced and heated to high temperatures in the furnace, melting at approximately 1,500°C. The furnace for melting glass is divided into a regenerative chamber, a melting chamber, and a working chamber, where the glass raw materials gradually transform into glass material.

In ancient times, coal was used as the heat source for melting glass raw materials, but today, petroleum, gas, and electricity are used. Gas is the most commonly used because it is easy to handle and heats up quickly. City gas is pre-mixed with air before delivery, which allows for efficient combustion and high temperatures of 1400°C to 1600°C. In comparison, the orange part of a candle flame is about 960°C. The temperature varies depending on the location of the fire, with the center being the hottest.

In handmade glass factories that use "crucible furnaces" with "neko kama," facilities are designed to circulate high-temperature air from burning gas, which then burns more gas, achieving a more efficient melting temperature.

In automated factories that use tank-type melting, the entire melting furnace is heated to a high temperature with gas. In the regenerative chamber, melting chamber, and working chamber, during the melting stage, gas is directed from above the furnace toward the raw material like a burner, directly applying fire for melting.

The process for manufacturing glass and glass bottles is almost the same, and the melting process for plate glass, such as window panes, is also nearly identical. Next time, I will talk about forming, the next step after blending and melting.