Wacker ELASTOSIL® M 4601 A/B – Pourable Addition-Cure Silicone for Moulds & Reproduction

Premium Pourable Addition-Cure Silicone for Professional Mould Making and Reproduction Applications

Wacker ELASTOSIL® M 4601 A/B is a pourable, addition-curing two-component silicone rubber that cures at room temperature, with a Shore A hardness of 28, a reddish-brown final product and exceptional resistance to common casting resins. With a pot life of 90 minutes and a curing time of 24 hours at 23°C, this product offers the process reliability professional mould makers require. The mixing ratio is 9:1 (A:B) by weight, with the platinum catalyst in component B — important: use only components with the same batch number. ELASTOSIL® M 4601 A/B is ideally suited for applications where shrink-free reproduction, high tear strength and durable moulds are essential.

Key Benefits

• Tear strength >30 N/mm: exceptionally high resistance to tearing – moulds with deep undercuts can be reused many times without damage during demoulding.
• Elongation at break 700%: maximum elasticity – complex geometries and fine details demould without deformation or residual stress in the mould.
• Linear shrinkage <0.1%: addition cure without chemical shrinkage – dimensionally stable copies with micrometre-level reproduction accuracy.
• Pot life 90 minutes at 23°C: ample working time – ideal for large moulds and vacuum de-airing beforehand without time pressure.
• FDA and BfR compliant for food contact: meets European (EC 1935/2004, BfR XV) and American (FDA 21 CFR §177.2600) food contact standards – suitable for culinary moulds and chocolate moulds.
• Excellent resistance to polyurethane: no adhesion problems or degradation with repeated use with PU and epoxy casting resins and plaster – no release agent required for well-sealed moulds.

Typical Applications

• Production of precise casting moulds for polyurethane, epoxy and plaster in art foundries and design studios
• Reproduction of sculptures, reliefs and architectural ornaments in museum and restoration contexts
• Manufacture of food-contact moulds for chocolate and sugarcraft
• Prototyping and series production in the automotive sector where dimensional accuracy is critical
• Composite moulding for fibre-reinforced materials with complex undercuts
• Artificial stone and decorative concrete casting where reusable moulds are required

Processing instructions:

1. Stir component A (white, viscosity 15,000 mPa·s) thoroughly before use. Mix component B (reddish-brown, 800 mPa·s) well too.
2. Weigh the components accurately in a ratio of 9 parts A to 1 part B (by weight). Use only components with the same batch number — mixing different batches can lead to curing problems.
3. Mix slowly and carefully in a figure-of-eight motion or with a slow-speed mixer to minimise air entrapment, until a completely homogeneous, streak-free mass is obtained.
4. Optionally de-air the mixture in a vacuum chamber for 5–10 minutes to remove residual air bubbles. This is recommended for fine reproduction details.
5. Pour the mixture slowly and from a single point into the mould within the 90-minute pot life to prevent air entrapment.
6. Allow the silicone to cure for 24 hours at 23°C. Curing can be accelerated by heat. Once fully cured, the mould is ready for use.

Manufactured by Wacker Chemie AG, global market leader in the development and production of silicones for industrial and technical applications.

Important Warning: Inhibition in Addition-Cure Silicones

Please note: This is an addition-cure silicone (platinum-cure). These silicones can be inhibited by sulphur, nitrogen, amino compounds and metal salts. If you are unsure whether the materials you are using (gloves, spatulas, moulds) contain these substances, do a small test first. Inhibiting substances are found in latex gloves, some plasticines, condensation-cure silicones, 1-component silicone sealants and certain 3D printing materials. If in doubt, apply a layer of polyvinyl alcohol (PVA) as a barrier layer.

Professional Support

ELASTOSIL® M 4601 A/B is a proven choice for professional mould makers who require precisely reproducible results at high volumes and with complex geometries. Contact us for technical data sheets, processing instructions or product advice.