Kit Sizes: 1kg / 5kg / 21kg Grade 370 rubber is a high tear strength rubber for the casting of polyurethane resins. Its high tear strength permits castings to be made with larger than normal under cuts. Due to its softness and flexibility, 370 rubber is particularly good for when there are deep undercuts. For casting in Clear PU plesae use Grade 400. Key Benefits: Good for deep undercuts High Tear Strength High elongation Easy degassing Chemically resistant Pot Life: 45-120 minutes. De-mould: 10 hours Mixed viscosity: 11,000 mPa.s Cured Properties: Shore A hardness: 15° Elongation at break: 622% Tensile strength: 2.8 MPa Tear strength: 20.18 kN/m Young’s modulus: 0.79MPa Linear shrinkage: 0.46% Min. service temperature: -50°C Max. service temperature: 200°C Pale blue (when mixed) Comes complete with hardener – mix-ratio is 5 parts of hardener to 100 parts of rubber.