素材
G-2 (Noritake)
Japanese: G-2（ノリタケ）
A commercially available refractory gypsum manufactured by Noritake. Originally intended for use with molten metal, it is widely used in Japan for kiln casting. It is readily available, and extensive operational know-how has been accumulated regarding its use.
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G-2 (Noritake) is a commercially available refractory plaster manufactured by Noritake Co., Ltd. It is widely used in Japan as a molding material for kiln casting, pâte de verre, and lost-wax casting (§15.1). Although it was originally developed as a investment material (plaster molding material) for metal casting, it was later adapted for glass casting, leading to the accumulation of technical expertise in this area. It is relatively easy to obtain at specialty stores and material suppliers in Japan, and its price is standard among commercially available refractory plasters.
The characteristics of G-2 lie in its moderate heat resistance (suitable for glass fusing temperatures ranging from 800 to 900°C) and its ease of demolding after shaping. However, like standard refractory gypsum, it contains sulfate (CaSO₄), and when combined with lead-based glass (such as Gaffer Casting Crystal), there is a risk of sulfidation and blackening (§5.1). Since the water-to-powder ratio and curing time may vary slightly depending on the product batch, it is recommended to conduct a test mix using a small batch when using this product for the first time.
Related Concepts
Understand the selection of refractory plasters in Japan, including Chikaoka-style homemade refractory plaster (chikaoka-plaster), refractory plaster (refractory-plaster), sulfide blackening (sulfide-blackening), and predry (preheating of plaster molds) (predry).
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.