Formstoffer

Formstoffer, or molding materials, are substances used to form molds or forms for replicating objects in crafts, sculpture, prototyping, and manufacturing. They are chosen for their ability to capture surface detail, their mechanical properties, and their compatibility with the casting material.

Types and properties

Elastomeric molding materials include silicone rubber, polyurethane elastomers, and alginate. They produce flexible or semi-flexible molds that can repeatedly reproduce fine details and are relatively resistant to tearing. Alginate is inexpensive and skin-safe, often used for lifecasting, but has limited durability. Rigid molding materials, such as plaster, gypsum, cement, and certain epoxies, create solid shell molds suitable for mass production or casting with less flexible materials. Some systems form a two-part mold that cures to a rigid shell, while others remain flexible.

Processing and use

Creating a mold typically involves preparing a master, building a mold box or support, mixing the molding material, and pouring or brushing it over the master. A release agent is usually applied to ease demolding. After curing, the mold is opened (if multi-part) and the master is removed. The mold can then be used to cast the desired material, which may be resin, concrete, wax, clay, or metal, depending on compatibility and heat resistance.

Safety and handling

Many molding materials contain chemicals that require ventilation and protective equipment. Use appropriate gloves, eye protection, and dust control where applicable, and follow manufacturer instructions for mixing ratios, pot life, and cure times.

See also

Mold making, casting, prototyping, release agents.