Condensation-Cure Silicone Rubber
Not sure what you need?Selection guide →Ask a specialist →
Filters
Sort Featured
Why choose condensation-cure silicone?
Condensation-cure silicones – also known as tin-cure silicone rubber or RTV silicone – are popular as mould-making silicone thanks to their ease of use and reliable results.
These liquid silicone rubbers are suitable for making silicone moulds and cure predictably at room temperature (room-temperature vulcanising silicone, RTV).
⚠️ Business customers only
These tin-cure condensation silicones may only be purchased by registered businesses that can safely handle the required B components. Sales to private individuals are not permitted.
Curing mechanism: curing takes place through a condensation reaction with tin compounds; formulations are based on PDMS (polydimethylsiloxane).
Who it is for: professional mould makers, restoration and sculpture studios, prop and SFX workshops, and industrial users casting concrete, plaster, wax, soap or resins.
Key benefits
- ✓Easy to use: pour, brush, inject or knead
- ✓Durable, with good chemical resistance
- ✓Fine detail reproduction (note slight shrinkage over the long term)
- ✓Forgiving to work with: cures at room temperature
- ✓Temperature resistant: once cured, typically from −20 °C to +180 °C
Application methods
- →Pourable silicones for high detail and complex shapes
- →Brushable silicones with a thixotropic agent for vertical surfaces
- →Kneadable silicones for quick block moulds and repairs
Processing & curing
Ideal conditions
Temperature: work at 15 to 30 °C with a relative humidity above 30 %.
Warning: above 60 °C the silicone may no longer cure properly.
- Cures at room temperature
- Adjustable with thixotropic agent and accelerator
- Suitable for small and large projects
Additives
Silicone Condensation Thixo C makes the mixture thixotropic for brushable layers.
Silicone Condensation Accelerator shortens curing and demould time.
- B components (catalysts) T21, T37, T47, T51
- Speed and hardness depend on the product
Compatibility with resins and casting materials
Important: not all condensation silicones are suitable for epoxy, clear PU or polyester.
For these applications, choose grades developed for the purpose, such as:
Always check the product page for compatibility and the right release agent.
Tips for the best results
Mixing & processing
- → Weigh accurately and mix thoroughly
- → Scrape the bottom and sides of the mixing cup
- → Degas under vacuum or pour in a thin stream
Mould-making techniques
- → Seal porous models beforehand
- → Use a suitable release agent with resins
- → Build up brush-on moulds in several thin layers
Storage & shelf life
- → Store components cool and dry
- → Close containers immediately after use
- → Observe pot life and demould time
Frequently asked questions
What is the difference between condensation and addition silicones?
Condensation silicones use tin catalysts, are often more affordable and can shrink slightly over the long term. Addition silicones (platinum cure) generally shrink less, but carry different inhibition risks.
Can I use condensation silicone with epoxy, PU or polyester?
Yes, but use grades designed for it, for example Dow SILASTIC RTV-3481 R, RTV-3481 Fast or Silicone Condensation 20 for PU & Epoxy.
What are the ideal curing conditions?
Work at 15 to 30 °C with humidity above 30 %. Avoid curing above 60 °C, as the reaction may fail.
How do I make silicone brushable?
Add Silicone Condensation Thixo C to a compatible base to create a non-sag mixture. Apply several thin layers for a strong mould.
Not to be confused with
RTV sealant and silicone spray for car rubber seals are different products from mould-making silicone.
- RTV sealant is a one-component sealant
- Silicone spray is a care product for rubber seals on cars
These are not part of our two-component mould-making silicones.
Get started
Order condensation-cure silicone for mould making and compare the grades for PU, epoxy and polyester. Download datasheets and contact us for practical advice and fast delivery across Europe.