Description
This tin-catalyzed silicone mold rubber cures to a Shore 30A hardness and is known for its very low long-term shrinkage. It is ideal for creating durable molds for casting chemically harsh resins like epoxies and polyesters, as well as urethane foams.
Features
- Mix ratio: 100A:10B by weight
- Pot life: 40 minutes
- Cure time: 24 hours at 23°C (73°F)
- Reproduces fine detail
- Can be thickened with THI‑VEX™ for brush-on applications
Vacuum degassing is recommended to remove entrapped air. Suitable for industrial and art applications, including production molds, prototypes, furniture, sculpture, and architectural elements.
Instructions
Formulated for high-detail mold making, this silicone rubber requires accurate weighing of Part A and Part B using a gram scale for proper curing. Conduct a small test mold to confirm suitability before full production.
Safety
- Use in a well-ventilated area
- Wear safety glasses, long sleeves, and vinyl gloves (latex gloves inhibit cure)
- Store and use at 23°C (73°F); higher temperatures reduce shelf life
Application
- Pre-mix Part B thoroughly
- Measure Parts A and B by weight and mix for 3 minutes, scraping sides and bottom
- Vacuum degas to remove air, achieving 29 inHg (1 bar, 100 kPa)
- Pour silicone from a single low point, allowing natural flow over the model
- Maintain a minimum thickness of 13 mm above the highest point
- Cure at 23°C for at least 16 hours before demolding; do not cure below 18°C
- For urethane casting, post-cure mold for 4 hours at 65°C (149°F), then cool fully
Additional Tips
- For brush-on molds, thicken with THI-VEX™ and apply multiple thin layers to a final thickness of at least 10 mm
- Accel-T™ can be added to accelerate cure, reducing working time and mold life
- Silicone Thinner™ may be added up to 10% by total weight (A+B) to reduce viscosity, improve flow, and extend working time, with some reduction in tensile properties
