Cast thermoset urethanes start out as liquid components which are accurately metered, mixed and dispensed by our special built machinery. Typically the pressures involved in dispensing do not exceed 100 psi and on average are less than 10 psi. Unlike injection tooling which must withstand thousands of psi, tooling for cast polyurethane is usually much less expensive -- great for prototyping and short- to medium-production runs. Liquid casting.