Premium Shrink-Free Addition-Cure Silicone for Professional Reproduction and Prototyping Applications
Elastosil M 4670 A/B is a pourable, addition-curing (platinum-cure) two-component RTV-2 silicone that cures shrink-free at room temperature and can be accelerated by heat. The cured rubber has a high hardness of Shore A 55 and a beige final color. The major strength of this silicone is its excellent resistance to casting resins combined with a high tear strength, which ensures molds with a long service life and dimensionally stable self-stability. With a pot life of 90 minutes, a curing time of 12 hours at 23°C, and a mixing ratio of 10 to 1 by weight, the material is suitable for the shrink-free and dimensionally stable molding of models with undercuts, and is moreover food-contact compliant (FDA and BfR) when processed correctly.
This product is intended for the business market. For larger quantities or custom products, you can contact us at info@nedform.com or +31 (0)46-3030989.
Key Benefits
-
Hardness Shore A 55 – relatively hard, dimensionally stable mold with good self-stability for models with undercuts
-
Tear strength 15 N/mm – high resistance to tearing ensures a long service life of the mold
-
Linear shrinkage < 0.1% – dimensionally stable, shrink-free molding with excellent reproduction accuracy
-
Tensile strength 5.5 N/mm² – strong vulcanizate with stable long-term mechanical properties
-
Pot life 90 minutes – ample processing time at 23°C for larger or complex moldings
-
Food-contact compliant FDA and BfR – suitable as a raw material for culinary and food-safe applications when processed correctly
Typical Applications
- Reproduction molds for casting resins such as polyurethane, epoxy, and polyester
- Composite molding in the automotive, marine construction, and wind turbine industries
- Prototyping of models with undercuts
- Precast concrete and wet cast in the construction industry
- Culinary and food-safe molds
- Props, set building, and design
Processing
- First stir the A-component and B-component thoroughly and separately.
- Mix the components in the weight ratio of 10 parts A to 1 part B. Note: use only A- and B-components with the same lot number.
- Mix slowly in a figure-8 motion without beating in air until a homogeneous mixture is obtained.
- Preferably degas the mixture under vacuum to remove air bubbles.
- Pour the mixture within the pot life of 90 minutes.
- Allow to cure for 12 hours at 23°C. The curing process can be accelerated in an oven; bear in mind that air bubbles then have less time to escape. We recommend post-baking the mold for 2 to 3 hours at 100°C after demolding for complete degassing.
Note: pot life and demold time are strongly dependent on the temperature. At a higher temperature, the processing time and demold time become shorter.
Wacker Chemie AG is the world market leader in the development and production of silicones for industrial and technical applications.
⚠️ Note: this is an addition-cure silicone (platinum-cure). These silicones can be poisoned (inhibited) by sulfur, nitrogen, amino compounds, and metal salts. If you are not sure whether the products you use (including gloves, spatulas, and cups) contain these ingredients, do a small test first. These substances occur, among others, in many latex gloves, some plasticines, varnishes and adhesives, condensation silicones, 1-component silicone sealant, natural rubbers, and 3D printing material (especially stereolithography). If you still want to use these, apply a protective layer of polyvinyl alcohol.
Food Contact
⚠️ The raw material is food-contact compliant according to EC 1935/2004, BfR XV, and FDA, but this does not mean that your finished mold is automatically food-safe. The product contains small amounts of residual toluene that must be completely removed from the end product, for example by full post-curing and degassing, before the mold may come into contact with food. The responsibility for the conformity of the finished mold, including any migration testing, lies with the manufacturer of the end product. Consult the safety data sheet and the regulatory product information for the full conditions.
Professional Support
Do you need advice on the right silicone for your reproduction or molds for casting resins? Silicones and More is happy to help. Contact us for personal advice, technical support, or a custom quote.
