Bluesil RTV 3318 SPU

Product description

BLUESIL® RTV 3318 SPU (formerly RTV 1320) is a specially formulated 2K silicone system for polyurethane casting applications. With its very soft Shore hardness (approx. 18), high elasticity, and excellent tear resistance, it is ideal for flexible molds with complex geometries that are frequently demolded. The formulation has been specifically developed to ensure excellent chemical compatibility with polyurethane resins. Thanks to its simple 1:1 processing ratio (by weight or volume), RTV 3318 SPU can be processed both manually and mechanically – even in vacuum processes.

product features

• Two-component silicone, addition-curing

• Mixing ratio 1:1 (weight or volume)

• Shore hardness A: approx. 18 – very soft, elastic

• Excellent for PU casting resin systems

• Tear resistance: very high, permanently flexible

• Shrink-free and dimensionally stable

• Temperature resistant: –140 °F to 392 °F

• Pot life: approx. 30 minutes

• Demolding time: approx. 6–8 hours

• Long service life, good abrasion resistance

• Vacuum processing possible

Suitable materials

• Polyurethane casting resins

• Epoxy, plaster, wax

• Model building materials such as wood, clay, plastic

• Concrete (with suitable release agent)

Typical areas of application

• PU-compatible casting molds with undercuts

• Flexible tools for small series production

• Prototype construction with complex geometry

• Decorative shapes with high detail requirements

• Elastic matrices for technical or creative applications

• Reusable molds in model and design manufacturing

Processing instructions

1. Stir both components well and homogenize separately.

2. Strictly adhere to the mixing ratio of 1:1.

3. Mix thoroughly and without bubbles

4. Vacuum ventilation recommended for fine structures

5. Curing at room temperature or accelerated with heat

6. Demolding after complete cross-linking

7. Do not use with materials containing sulfur, amines, or tin.

8. Storage: dry, airtight, between 5–30 °C