Premium Sprayable Addition Silicone for Professional Vacuum Bag and Composite Mold Making Applications
Wacker Elastosil® C 1200 A/B is a two-component, platinum-catalyzed addition-curing RTV-2 silicone, developed for the industrial production of reusable vacuum bags in the composites industry. The silicone has a low viscosity (8,000 mPa·s mixed) and is shear-thinning: self-leveling on horizontal surfaces, but stays put on vertical walls without running. It can be processed by brushing, spraying, or pouring. With a Shore A hardness of 25, a tensile strength of 5.0 N/mm², and an elongation at break of 500%, the material combines flexibility with the mechanical strength required for hundreds of vacuum cycles. Mix ratio 1:1 by weight, pot life 20 minutes, demoldable after 60 minutes at room temperature. The blue color of component B provides visual mixing control. Resistant to epoxy and polyester resins.
Key Benefits
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Shore A 25 – flexible enough to conform to complex shapes and be repeatedly rolled for transport and reuse
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Tensile strength 5.0 N/mm² and tear strength 25 N/mm – high mechanical load capacity for industrial vacuum cycles, measured according to ISO 37 and ASTM D 624 B
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Pot life 20 minutes, demoldable after 60 minutes – ample processing time for large surfaces combined with fast production turnaround
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Viscosity 8,000 mPa·s with shear-thinning behavior – self-leveling on horizontal surfaces and stable on vertical walls without sagging
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No chemical shrinkage – dimensionally stable molds and bags, critical for reproducible composite production
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Resistant to epoxy and polyester resins – suitable for common reproduction and infusion materials in the composites industry
Typical Applications
- Reusable vacuum bags for resin infusion of glass and carbon fiber
- Composite panels for commercial vehicles, trains, and buses
- Aircraft and shipbuilding with fiber-reinforced plastics
- Large-scale mold making for serial composite parts
- Spray-up production of vacuum bags on large and complex shapes
- Industrial infusion processes with epoxy and polyester systems
Target Audience
This product is developed for industrial processors in the composites industry and is not intended for general mold making or hobby applications. The material costs, processing equipment (spray or dosing unit), and post-curing at operating temperature make the product economically viable for serial composite production.
Processing Instructions
- Briefly stir components A and B separately before processing.
- Mix A and B in a weight ratio of 1:1. Important: only process components A and B with the same batch number. Component A contains the platinum catalyst. The manufacturer excludes combinations of different batch numbers.
- Mix slowly and evenly until a homogeneous blue color is achieved, either mechanically or via a static mixer in the dual cartridge.
- Optional vacuuming for casting applications to remove air inclusions.
- Process within 20 minutes. Application can be done via a manual or pneumatic cartridge gun with a static mixer, a 2-component mixing and dosing machine, or via compressed air spraying for large surfaces. For small or free-form applications, brush application is also possible.
- Allow to cure at room temperature: demoldable after 60 minutes, fully cured after 24 hours at 23 °C.
- For maximum dimensional stability of the vacuum bag: post-cure for 2 to 3 hours at the intended operating temperature, up to a maximum of 220 °C.
⚠️ Inhibition warning for addition silicone
Platinum-catalyzed addition-curing silicones are sensitive to inhibition. Avoid contact with: condensation silicones or their residues, latex and natural rubber, sulfur-containing clay, uncured polyester resin, tin compounds, and amine-containing substances. If in doubt, always test a small area before starting the full application.
About Wacker Chemie AG
Wacker Chemie AG is a global market leader in the development and production of silicones for industrial and technical applications. The Elastosil® C series is specifically developed for the composites industry and is used worldwide in vacuum bag technology for production processes where reproducibility and long service life are critical.
Packaging and cartridges
Silicones and More offers Elastosil® C 1200 A/B in 10 kg kits, 40 kg kits, and in 1.5 kg dual cartridges. Please note: the dual cartridges we produce are not identical to Wacker's original cartridges. For the cartridge variant, you may need a different dispenser gun.
Storage
Store cool and dry in the original packaging. The best-before date is on the product label. Storage beyond this date does not automatically mean the product is unusable — in this case, check the critical properties for your application before using the material in production.
Professional Support
Are you working on a specific composite or vacuum bag application and want to know if Elastosil® C 1200 A/B is the right choice for your project? Our technical specialists are happy to assist with material selection, process steps, and alternatives within the Wacker portfolio. Contact us via chat, email, or phone.
