Platinum-cure silicone
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Why choose platinum-cure silicone?
Platinum silicones are silicone rubbers that cure through an addition reaction with a platinum catalyst, which is why they are also called addition-cure silicones. This reaction produces no by-products, resulting in a stable structure with very low shrinkage, high tear strength and a flexible, rubbery end product – ideal for accurate silicone moulds.
Platinum silicones, also known as RTV-2 addition silicones, combine dimensional stability with easy processing. They are available as clear or colourless versions and as pourable, brushable or kneadable systems for a wide range of projects.
Addition-cure casting rubbers are a specific class of silicone rubber that give a pleasant, rubbery and flexible result after curing. Also known as platinum silicone or RTV-2 silicone.
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Compare all platinum silicones by hardness, flowability, tensile strength and more
Cure mechanism: Platinum-catalysed addition reaction, curing at room temperature. Gentle heat can accelerate curing where the product allows it.
Who it's for: Mould makers, restoration and sculpture studios, prop and SFX workshops, culinary creators and serious beginners looking for skin-friendly, low-shrinkage silicone moulds.
Key Benefits
- ✓Stable cure addition reaction with platinum catalyst for a durable structure
- ✓Flexibility highly flexible without loss of integrity
- ✓Low shrinkage accurate fit and repeatability over many casts
- ✓Skin and food many grades are skin-friendly and suitable for food contact
- ✓Processing freedom pourable, brushable, kneadable, clear and easy to pigment
Application Methods
- →Pourable for high-detail negatives, pour in a thin stream
- →Brushable with thixotropic agent for vertical surfaces
- →Kneadable putty for quick hand moulds and impression moulds
- →Spreadable or trowelable for thin shells and coatings
Processing & Curing
Ideal Conditions
Temperature: Work at around 20 to 25°C on clean, dry models.
Environment: Avoid draughts and extreme temperatures; observe the pot life and demould time.
- For food contact: post-cure when recommended
- Allow to cure fully at room temperature
- Gentle heat can accelerate curing
Modifiers
Thixotropic agent creates a non-sag, brushable mixture for building up layers.
Deadener softens platinum silicone towards a gel-like feel for prosthetics and SFX.
- Pigments and effects for platinum silicone
- Glow-in-the-dark powder, glitter, magnetic powder
Inhibition Checklist
Warning: Addition-cure silicones can be inhibited by contaminants. Always do a small test and avoid:
- Sulphur-containing clay, latex and natural rubber
- Certain amines and not fully cured epoxy
- Fresh paints and tin residues from condensation-cure silicones
- Contaminated tools or models
Advice: Keep models and tools clean and always test on a small area.
Tips for the Best Results
Mixing & Processing
- → Measure by weight and mix thoroughly
- → Scrape the sides and bottom of the cup
- → De-air under vacuum or pour in a thin stream
Mould-Making Techniques
- → Seal and prime porous masters
- → Choose the right release agent for each system
- → Build up brush-on moulds in thin layers
Food Contact
- → Use suitable grades only
- → Carry out the prescribed post-cure
- → Follow the instructions carefully
Compatibility with Resins and Casting Materials
Addition-cure silicones can be used widely with epoxy, polyurethane and polyester. The combination of low shrinkage and high tear strength makes them suitable for repeated casting.
Important: Seal porous models, use a suitable release agent for each system and follow the recommendations for each product.
Frequently Asked Questions (FAQ)
What are addition-cure casting rubbers?
Platinum-catalysed silicones that cure at room temperature into a flexible rubber with very low shrinkage and high tear strength.
What is the difference between addition-cure and condensation-cure silicones?
Addition-cure silicones offer low shrinkage and consistent properties but can be inhibited by sulphur, latex and some amines. Condensation-cure silicones are often more economical and easier to process but may shrink slightly over time.
Are these silicones skin-friendly or suitable for food contact?
Many platinum silicones are suitable for skin contact, and specific lines are suitable for food contact. Only use products that clearly state this and follow the instructions, including post-curing.
How do I make a brushable platinum silicone?
Add a thixotropic agent to a compatible base, make a non-sag mixture and apply several thin layers. Let each layer gel before applying the next.
Get Started
Discover our range of addition-cure silicones – clear or soft, brushable or pourable. Add thixotropic agent or deadener where needed and start on an accurate silicone mould today.
