Alpha plaster and beta plaster are two different types of calcium sulphate hemihydrate that are used to produce high strength, quick setting plasters for creating smooth surfaces and ornamental designs on ceilings, walls and floors. It can be used in fire-proofing material and in the production of moulds for ceramics and roof tiles. It can be used as an accelerator in oil & gas well cementing . Alpha plaster is created by heating gypsum to a higher temperature than the more common beta plaster (calcium sulphate hemihydrate), resulting in a different crystalline structure and distinct properties.

While there are several similarities between alpha and beta plasters, they also have distinct differences. The most significant difference between these plasters lies in their setting characteristics and physical properties. Typically, this difference is what makes alpha and beta suitable for various applications.

What Is Alpha Plaster?

Alpha plaster or Type II plaster is a type of calcium sulphate hemihydrates with a different crystalline structure compared to beta plaster. It has the chemical formula CaSO4·1/2H2O. It is obtained by calcining the naturally occurring gypsum. Alpha plaster can be used to produce molds for roof tiles and ceramics or as an accelerator in oil and gas well cementing.

What Is Beta Plaster?

Beta plaster or Type I plaster is a type of calcium sulphate, also known as calcium sulphate dihydrate, and also has the chemical formula CaSO4·1/2H2O. It is produced by heating gypsum under a lower temperature to achieve higher compressive strength and a slower setting time.

Beta plaster is primarily used in casting projects and general construction. Here are the major differences between alpha and beta plasters:

  • Crystal Structure

Alpha plaster has a denser crystal structure consisting of smaller, more uniform crystals. It forms a fine, densely packed structure with a sharp, circular shape. This structure contributes to the increased strength and hardness of alpha plaster when it is fully set.

On the other hand, the crystal structure of beta plaster has larger and irregular-shaped crystals. These crystals are more randomly structured compared to the concentrated and uniform design of alpha plaster. The irregular shape and bigger crystal shape contribute to the reduced strength and hardness of the beta plaster compared to alpha.

  • Setting Time

Alpha Plaster: Alpha plaster has a relatively fast setting time. It hardens and reaches its final strength more quickly, making it suitable for applications where rapid setting is required.

Beta Plaster: Beta plaster has a slower setting time compared to alpha plaster. It provides more working time before it sets, which can be advantageous for certain casting and molding applications.

  • Strength and Hardness

Alpha plaster demonstrates higher strength and hardness when fully set. This makes it perfect for applications requiring a sturdy and durable material. Conversely, beta plaster is not as strong and hard as alpha, making it a good choice for applications that require less strength. It is commonly used for general-purpose plaster applications in construction.

Buy Alpha And Beta Plasters From Bisley Company

Bisley Company is a proud supplier of top-quality raw materials, including alpha and beta plasters. Contact us for inquiries and place your bulk order to get started.