Sodium Bentonite

Sodium bentonite is a western-style swelling bentonite used as a primary bond clay in green sand systems for iron, steel, and other hotter-pouring foundry work where high dry strength, hot strength, and mold durability matter.

Compared with calcium bentonite, sodium bentonite holds more water, swells much more, and develops stronger dry and hot properties, helping molds retain dimensional accuracy and resist erosion in demanding pours. Foundries often use it alone for maximum hot performance or blend it with calcium bentonite to tune mulling response, shakeout, and overall bond balance.