W, X, Y, Z - Foundry Additives Glossary
WAD ORE (See: MANGANESE DIOXIDE)
WATER GLASS (See: SODIUM SILICATE)
"Sodium silicate," "soluble glass," and "silicate of soda" are all called "water glass." Water glass is a composition of various ratios of Na, O to SiO, in dry crystalline or hydrated form. It is used as a binder in mold and core sand mixtures. The Carbon Dioxide (C02)-Sodium Silicate Process is used by the foundry industry. When 2% to 4% sodium silicate (Water Glass) is added to a clean silica sand or a refractory sand and carbon dioxide gas is passed through this formed mold or core, it hardens into a refractory mass, making excellent cores and molds for certain castings. Sodium silicate dissolves in hot water. Sodium silicate (water glass) is made by melting sodium carbonate with silica or by applying heat and melting sodium carbonate together with sand, charcoal and soda. This product, fused sodium silicate, is then ground and dissolved in boiling water for use as a foundry binder. Sodium and potassium carbonate can also be made into a double soluble water glass.
WATERLESS BINDERS (See: NEO-BOND)
Neo-Bond is a waterless binder which is very popular in the foundries where waterless binders are required. No temper water is necessary. Five percent (5%) by weight Neo-Bond, plus less than 2% of a high viscous coastal oil is all that is required when mulled together to form a waterless molding sand mixture. Waterless binder mixtures have produced, and are producing castings, with better detail than more expensive processes such as shell molding. Such waterless mixtures are molded "green" and are generally a low cost repetitive operation. Waterless binders, such as Neo-Bond, are used with fine silica sands, olivine, zircon, or Hevi-Sand mixtures.