Remix each of the two components (base and CATA SPU) every time before using.

1. Mixing of the two components

To 100 parts of BLUESIL RTV 3318 SPU, RTV 3330 SPU or RTV 3335 SPU add 5 parts by weight of BLUESIL CATA SPU. The two components are thoroughly mixed either using an electrical or pneumatic mixer, on a low speed setting so as to limit the inclusion of air in the mixture as well as the temperature rise.

2. Degassing

After mixing BLUESIL RTV 3318 SPU, RTV 3330 SPU or RTV 3335 SPU with BLUESIL CATA SPU, it is recommended to eliminate entrapped air.

The catalysed BLUESIL RTV 3318 SPU, or RTV 3330 SPU or RTV 3335 SPU is degassed under a vacuum of 30 to 50 mbar. Under vacuum, the product expands 3 to 4 times its initial volume and forms bubbles on its surface. These bubbles will disappear gradually and the mixture will sink back down to its initial volume within few minutes. Then the vacuum can be released.
Remark: releasing the vacuum several times improves the degassing. For easier degassing fill the recipient only to 1/3 of its height.

3. Cross linking

The best curing conditions are at 23°C and 50% relative humidity. The use of the products at higher temperatures and / or relative humidity levels will reduce the pot life and increase the curing rate. As opposed to this, lower temperatures and relative humidity levels will increase the pot life and decrease the curing rate. It is suggested not to place the catalysed product, during or after crosslinking, to temperatures above 50°C. At 23°C and 50% relative humidity, the moulds of BLUESIL RTV 3318 SPU, RTV 3330 SPU or RTV 3335 SPU can be demoulded after 24 hours, with no dependence on the mold thickness. In order to achieve the best possible performance levels from the moulds, it is preferable to wait for 4 days before using them.

4. How to use

Apply BLUESIL RTV 3318 SPU, RTV 3330 SPU or RTV 3335 SPU mixed with BLUESIL CATA SPU directly on the model by casting, trying to avoid bubbles and voids. Models can be made of several materials, stones, concrete, metal, etc. Even though silicone is naturally not adhering to most materials, it is always recommendable to prepare the model to avoid any risk of the silicone sticking and so damaging the model. Remove dust and apply a pore filler like soapy water, waxes diluted in xylene, etc. Part used drums should be resealed between each use.

BLUESIL RTV 3318 SPU may be stored at a temperature below 40°C / 104°F for up to 12 months from its date of manufacturing.Please consult the Safety Data Sheet of this product.


BLUESIL RTV 3318 SPU, RTV 3330 SPU and RTV 3335 SPU are silicone elastomers which, after the addition of catalyst BLUESIL CATA SPU, cure at room temperature by a polycondensation reaction, leading to a flexible and elastic material.


2 Part RTV

  • Very high resistance to polyurethane resins, even to those curing by a strong exothermic reaction
  • Ease of processing thanks to the good flowing behaviour.
  • High mechanical resistance.
  • Excellent reproduction fidelity of each detail.
  • Easy demolding thanks to the intrinsic self-releasing properties of silicone elastomers.
  • Possibility to choose between three different hardness levels: 18 - 30 - 35 Shore A.

BLUESIL RTV 3318 SPU, RTV 3330 SPU and RTV 3335 SPU have been specifically designed for the production of molds dedicated to polyurethane resins casting, for series production.
The use of the products can be suggested also for molds where other replication materials are casted (such as e.g. wax, plaster...).

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Viscosity25000PairedCompRH 0174mPa.s




ColorPale YellowPairedComp






hardness_cd523e03-72a3-4261-93f9-36f7bbeeafb1hardness_cd523e03-72a3-4261-93f9-36f7bbeeafb1Hardness18PairedMixRH 0149sh.A
pot-life_0d649a54-7503-4c7c-a047-9d0c4b3e9f6apot-life_0d649a54-7503-4c7c-a047-9d0c4b3e9f6aPot life150PairedMixRH 0114min





















Under The Skin Of a Silicone Artist The Skin Of a Silicone Artist
















BLUESIL RTV 3330 SPUBLUESIL RTV 3330 SPU/our_offer/Product/90051510/90039344/BLUESIL-RTV-3330-SPU
BLUESIL RTV 3335 SPUBLUESIL RTV 3335 SPU/our_offer/Product/90059213/90039344/BLUESIL-RTV-3335-SPU