Rust Prevention (Kanake-dome)
Once the casting is finished and the core is removed, the tea kettle is baked once again in charcoal at 900ºC. This process of creating an oxide film inside the kettle to prevent rust is unique to Nambu Tekki. Furthermore, the surface of the kettle is covered with lacquer, using a special brush made from bundled water-grass called kugo-hake. Finally, it is coated with rust-preventing liquid made by putting bits of steel in acetic acid and brewed tea, known as ohaguro. Then it is wiped carefully, the handle is attached, and the lid is put in place. The Nambu tetsubin is now complete.