Platinum Cure Silicone Rubber for Professional Mold Making

1. Description

BKSilicone^® BK-A Series is a high-performance, two-component platinum-cure silicone elastomer that cures at room temperature via an addition-catalyzed reaction.

This series has been used and validated in BKSilicone’s own factory for many years as a standard production material for silicone mold manufacturing. It features a 1:1 mixing ratio by weight, low initial viscosity with natural self-degassing behavior, and fast room-temperature curing, enabling efficient processing with minimal equipment.

BKSilicone BK-A Series Platinum Silicone

2. Features

Platinum-catalyzed addition cure system: Clean curing at room temperature with no by-products.
Simple 1:1 mixing ratio by weight: Ensures consistent and repeatable processing.
Low initial viscosity: Good flowability enables easy pouring and natural self-degassing behavior.
No chemical shrinkage: Provides excellent dimensional stability after curing.
High elasticity & Tear strength: Supports reliable demolding and long mold service life.
Excellent Chemical Resistance: Compatible with polyurethane, epoxy, polyester resins, wax, and gypsum.

3. Applications

BKSilicone® BK-A Series is designed for professional mold making and casting applications where softness, flexibility, and reliable demolding are required. This series has been extensively used and validated in BKSilicone’s own factory production.

Candle Molds

Silicone molds for pillar candles, container candles, and decorative candle designs requiring clean surface finish and stable demolding.
Concrete & Cement Molds

Flexible molds for small concrete items, architectural details, and decorative cement components.
Fondant & Cake Decorating

Molds for sugar paste, fondant, and cake decoration elements where fine detail reproduction is required. *Verify food-contact compliance per local regulations.

Plaster & Aroma Stone

Casting molds for gypsum, plaster, and aroma stone products with repeated production cycles.
Creative & Character Molds

Silicone molds for figurines, decorative objects, and custom creative designs with complex geometries.
Lightweight Mold Designs

Thin-wall and reduced-material molds optimized for cost efficiency while maintaining structural stability.

4. Processing Notes

Batch Consistency: Always use Part A and Part B from the same production batch. If components from different batches must be mixed, conduct a small-scale test first.
Compatibility Testing: A preliminary test is strongly recommended to confirm compatibility with specific substrates, mold materials, or additives prior to large-scale production.
Mixing & Curing Conditions: For optimal performance, mix and cure at an ambient temperature of 20–30 °C (68–86 °F) with relative humidity below 50%.
Minimum Application Temperature: Do not process below 15 °C (60 °F). Lower temperatures may significantly slow curing or result in incomplete crosslinking.

CURE INHIBITION WARNING

Platinum-cure silicone systems are sensitive to certain contaminants. Ensure all tools, containers, and model surfaces are clean. Avoid contact with materials containing:

Sulfur (e.g., sulfur-based clays, latex gloves)
Tin compounds (condensation-cure silicone rubbers)
Amines (certain epoxy systems and curing agents)
Unsealed LCD / DLP 3D printed resins

Contact with these materials may result in surface tackiness or incomplete curing. A small test cure is always recommended.

5. Safety Precautions

Under normal storage and handling conditions, this product is stable and does not present unusual hazards. Standard industrial hygiene and safety practices should be followed at all times.

General: Keep out of reach of children. Use only as intended.
Skin Contact: Wash thoroughly with soap and water after contact. Remove contaminated clothing if necessary.
Eye Contact: Rinse immediately with clean water for at least 15 minutes. Seek medical attention if irritation persists.
Inhalation: Ensure adequate ventilation during mixing and processing.
Ingestion: Do not induce vomiting. Rinse mouth and seek medical attention promptly.

*For detailed health, safety, and regulatory information, please refer to the Material Safety Data Sheet (MSDS).

6. Storage & Shelf Life

Storage Conditions: Store in a cool, dry place at room temperature 15–25 °C (60–77 °F). Keep containers tightly closed and away from direct sunlight, moisture, acids, and bases.
Shelf Life: 24 months from the date of manufacture when stored in unopened original containers. Exposure to elevated temperatures may reduce shelf life.
Opened Containers: Reseal immediately after use to prevent contamination and moisture ingress. Use clean tools to avoid introducing cure inhibitors.

Step 1: Master Pattern Preparation

Start with a clean slate. Ensure your master model is completely free of dust, oil, and moisture. If the model is made of porous materials (such as wood, plaster, or 3D printed resin), it must be properly sealed to prevent silicone penetration or cure inhibition. Finally, secure the pattern firmly within the mold box to prevent it from floating during pouring.

Step 2: Applying Release Agent (Optional)

While our platinum silicone offers excellent release properties, applying a release agent is recommended for models with complex geometries, deep undercuts, or porous surfaces. A thin, even mist of a silicone-appropriate release agent can facilitate easier demolding and extend the mold's lifespan. Note: Ensure the release agent does not contain sulfur or other substances that inhibit curing.

Step 3: Precise Measuring & Mixing

Accurately weigh Part A and Part B in a strict 1:1 ratio by weight. Pour them into a clean mixing container. Stir the mixture thoroughly, making sure to scrape the sides and bottom of the container to ensure no unmixed material remains.

Step 4: Vacuum Degassing

To achieve a professional, bubble-free mold, vacuum degassing is highly recommended. Place the mixing container into a vacuum chamber. Since the silicone will expand significantly under vacuum, ensure the container is 3 to 5 times larger than the liquid volume. Degas until the mixture rises, breaks, and collapses, then hold for an additional 1-2 minutes. Ensure this process is completed within the material's pot life.

Step 5: Pouring Technique

Pour the degassed silicone immediately. Do not pour directly onto the model; instead, pour a thin, high stream into the lowest corner of the mold box. Let the silicone flow naturally up and over the model, which helps push out trapped air. Ensure the silicone covers the highest point of the model by at least 0.5 cm (approx. 0.2 inches).

Step 6: Curing & Demolding

Allow the mold to cure undisturbed at room temperature (25°C / 77°F). Typically, the silicone will fully cure within 2 to 3 hours. Please note that temperature significantly affects curing speed: heat accelerates the process, while temperatures below 15°C (60°F) may result in slow or incomplete curing. Verify the mold is hard and tack-free before demolding.