Premium Condensation Silicone for Professional Resin and Concrete Molds

Dow Silastic RTV 3481 R is a high-quality 2-component condensation-curing (tin-cure) casting silicone with Shore A 18-21 hardness, specially developed for making durable molds resistant to aggressive resins such as polyurethane and polyester. This professional silicone combines excellent flowability (self-deairing), high mechanical strength (46 kg/cm² tensile strength) and 622% elongation with broad chemical resistance, ideal for art casting, WetCast concrete, and industrial molds. Flexible mixing ratio 100:4-6 (A:B) for adjustable cure speed.

Key Benefits

• Resistant to aggressive resins: Suitable for polyurethane, polyester, concrete, wax, and soap – ideal for industrial and artistic foundries
• Excellent flowability: Viscosity 20,000 mPa·s for self-deairing casting without vacuum treatment
• High mechanical strength: 46 kg/cm² tensile strength and 26 kg/cm² tear strength for long-lasting, durable molds
• Extreme elongation: 622% elongation at break for easy demolding of complex geometries
• Adjustable cure speed: 4% B-component for longer pot life (air bubbles escape), 6% for faster production
• Minimal shrinkage: 0.2-0.4% linear shrinkage for dimensionally accurate reproductions

Typical Applications

• Molds for polyurethane and polyester casting resin in art casting and industrial production
• WetCast concrete molds for precast elements, tiles, and architectural ornaments
• Art casting: molds for statues, sculptures, and decorative objects
• Model making and prototyping for small series and test parts
• Honeycomb and wax-casting applications
• Industrial molds for ornaments, reliefs, and architectural elements

Processing Instructions:

1. Mix A and B components in a 100:5 ratio (preferably 50g B per 1 kg A)
2. Vary B component: 4% for longer pot life, 6% for faster curing
3. Mix carefully by hand or machine
4. Pour within the pot life of 90-120 minutes
5. Wait until fully cured before demolding (max 24 hours)

Brush-on molds: Add 0.6-2% Thixo C (typically 1%) to thicken the mixture for brush-on applications. Combine with a support shell of plaster (bandage), kneadable epoxy or acrylic resin with fiberglass cloth.

Please note: Temperature and humidity affect the curing speed. Higher temperature and humidity shorten the processing time. Not suitable for epoxy resins.

Dow is a global leader in silicone technologies for professional foundries, architectural applications, and industrial molds with decades of expertise in condensation silicones.

Professional Support

Our technical specialists advise on mixing ratios, curing speeds, support shell construction, and optimal results for your specific resin or concrete mold application. Contact us for technical datasheets or advice on condensation silicones for your project.