Downloads (2)

This is a chemical product. Before storage or use you must download and read the accompanying safety and technical datasheets.

Safety Datasheet (SDS)220 KB
Technical Datasheet (TDS)282 KB

Specification

Product Data
ColourGrey
Chemistry / MaterialRTV Silicone Rubber
Viscosity23000mPa.s
Pot Life (Typical)75mins
Initial Cure Time25Hrs
Cured Mechanical Properties
Max Service Temp250°C
Hardness25Shore A
Linear Shrinkage<1.0%
Tensile Strength4.0MPa
Elongation at Break525%
Tear Strength17.5kN/m
Weight and Dimensions
Density1.09g/cm³
General Properties
Gross Weight0.616kg

Shipping Information

In the currently selected pack size, this product is classed as 'Limited Quantity Dangerous Goods' for the purposes of transport. This means that transport restrictions apply to certain destinations.

No restrictions or surcharges shipping by road to:

UK, Ireland, Channel Islands, Isle of Man, Austria, Belgium, France, Germany, Luxembourg, Monaco, Netherlands, Norway, Finland, , Czech Republic, Denmark, Hungary, Italy, Poland, Portugal, Spain, Andorra, Switzerland, Estonia, Latvia, Lithuania, Slovakia, Slovenia, Sweden

Shipping possible by airfreight (£55 surcharge applies) to:

United States, Finland, Bahrain, Hong Kong, Japan, Republic of Korea, Kuwait, Singapore, Taiwan, United Arab Emirates, Trinidad and Tobago

Can't ship to:

All other countries. If your country is not listed above then unfortunately we can't ship this product to you.

For very large orders, specialist shipping can be arranged. Please contact us to discuss.

CS25 Condensation Cure Silicone Rubber

CS25 is an easy-to-use condensation cure (also known as tin cure) RTV silicone rubber suitable for the production of silicone moulds. It cures opaque grey to a 25 shore A (soft flexible) hardness.

Sold as a kit (silicone and catalyst). Available to buy online in 500g, 1kg, 5kg and 26.25kg kits.


PRODUCT VERSIONS

Kit Size

AVAILABILITY:More than 10 availablefor immediate shipping


PRICE
£12.00inc. VAT
(£24.00 /KG)
More than 10 availablefor immediate shipping
QTY
EACH
EACH
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If you believe you’re buying an equivalent product cheaper elsewhere, contact us to discuss your requirements.

Easy Composites' CS25 Condensation Cure Rtv Silicone Rubber is a low viscosity, two-part condensation cure silicone rubber. It is used for silicone mould making where it is mixed (with its catalyst) and then poured around a pattern to create a flexible silicone mould.

CS25 has been specially selected for its ease of use, excellent performance and great value.

Once cured the silicone rubber is very soft and flexible making it perfect for casting complicated or intricate shapes where the cast part can be easily removed from the silicone mould. The long pot-life of our silicone allows plenty of time for careful pouring and self de-gassing although forced degassing in a vacuum chamber can also be performed if required.

Typical Uses

The cured mould can then be used to produce precise replicas of the original part, including fine surface detail, out of a range of materials including polyester, epoxy and polyurethane resin, urethane foam, wax, casting plaster, Jesmonite, and reconstituted stone. This Silicone should not be used with Water Clear Casting Resins such as the Water Clear Polyester or Polyurethane Resins as the inherent moisture content of this type of silicone can inhibit the curing of the resin. It can however be used with our GlassCast® clear epoxy range.

Advantages

  • Easy to use - no special equipment or conditions required
  • High tear strength and excellent elongation (making removal of even complex shapes from the mould easy)
  • Good chemical resistance to styrene and polyurethane
  • Low viscosity - fantastic flow properties
  • Great value!

Further Information

Mixing Ratio

100 p.b.w. CS25 Condensation Cure Silicone Rubber
5 p.b.w. CS25 Condensation Cure Silicone Rubber Catalyst

Brief Description of Typical Use

A part to be copied is positioned within a 'setup box' which will contain the silicone rubber whilst it cures.

The silicone rubber is thoroughly mixed with its catalyst at the correct ratio by weight and then carefully poured all over the surface of the part to be copied (the master). Once the surface of the part is covered the remainder of the silicone is poured into the setup box. The silicone will cure at room temperature in around 24hrs. Once the silicone has cured it is removed from the setup box and then the flexibility of the rubber is used to allow removal of the part from inside the new silicone rubber mould.

An example of a simple mould pour using the CS25 can be seen in the following tutorial video:

How to Make a Silicone Mould

Compatibility Information - Dos and Don'ts

Although by no means an exhaustive list, the mould materials, pigments and additives listed below have all been tested and are known to work well with AS40 Addition Cure Silicone.

  • Compatible Moulds
  • Almost all Plastic moulds
  • Metal moulds
  • Condensation Cure Silicone moulds with a release agent
  • Compatible Pigments
  • RTV Silicone Colour Pigment (for vivid opaque colours)
  • Translucent Tinting Pigment (for less vivid opaque colours)

Key Processing Information

  • Ease of Use
  • Suitable for professional and hobby use (follow SDS advice).
  • Odour/b>
  • CS25 is almost odourless.
  • Safety Precautions/b>
  • Wear gloves and goggles and work in a well ventilated area. Always read the SDS before use.
  • >Ambient Conditions/b>
  • Can be used from 10 to 30°C although pot-life and cure time will be affected significantly.
  • Degassing/b>
  • Although CS25 will self degas, we recommend degassing for the best results.
  • Mix Ratio

    Mix silicone and Catalyst 100:5 by weight. Use digital scales.

  • Mixing/b>
  • Mix thoroughly by hand for at around 2 minutes.
  • Pot-Life/b>
  • 60-90 Minutes. Be sure to pour your casting(s) before this time.
  • Cure Time/Demould/b>
  • Demould Time 24 Hours @ 25°C

Pack Size

Easy Composites' CS25 Condensation Cure Silicone Rubber is available in the following pack sizes: 0.5kg, 1kg and 5kg. Please choose the pack size you require from the drop-down list. The 1kg kit is also included in the Xencast Resin Casting Starter Kit.

Easy Composites' CS25 Condensation Cure Rtv Silicone Rubber is a low viscosity, two-part condensation cure silicone rubber. It is used for silicone mould making where it is mixed (with its catalyst) and then poured around a pattern to create a flexible silicone mould.

CS25 has been specially selected for its ease of use, excellent performance and great value.

Once cured the silicone rubber is very soft and flexible making it perfect for casting complicated or intricate shapes where the cast part can be easily removed from the silicone mould. The long pot-life of our silicone allows plenty of time for careful pouring and self de-gassing although forced degassing in a vacuum chamber can also be performed if required.

Typical Uses

The cured mould can then be used to produce precise replicas of the original part, including fine surface detail, out of a range of materials including polyester, epoxy and polyurethane resin, urethane foam, wax, casting plaster, Jesmonite, and reconstituted stone. This Silicone should not be used with Water Clear Casting Resins such as the Water Clear Polyester or Polyurethane Resins as the inherent moisture content of this type of silicone can inhibit the curing of the resin. It can however be used with our GlassCast® clear epoxy range.

Advantages

  • Easy to use - no special equipment or conditions required
  • High tear strength and excellent elongation (making removal of even complex shapes from the mould easy)
  • Good chemical resistance to styrene and polyurethane
  • Low viscosity - fantastic flow properties
  • Great value!

Further Information

Mixing Ratio

100 p.b.w. CS25 Condensation Cure Silicone Rubber
5 p.b.w. CS25 Condensation Cure Silicone Rubber Catalyst

Brief Description of Typical Use

A part to be copied is positioned within a 'setup box' which will contain the silicone rubber whilst it cures.

The silicone rubber is thoroughly mixed with its catalyst at the correct ratio by weight and then carefully poured all over the surface of the part to be copied (the master). Once the surface of the part is covered the remainder of the silicone is poured into the setup box. The silicone will cure at room temperature in around 24hrs. Once the silicone has cured it is removed from the setup box and then the flexibility of the rubber is used to allow removal of the part from inside the new silicone rubber mould.

An example of a simple mould pour using the CS25 can be seen in the following tutorial video:

How to Make a Silicone Mould

Compatibility Information - Dos and Don'ts

Although by no means an exhaustive list, the mould materials, pigments and additives listed below have all been tested and are known to work well with AS40 Addition Cure Silicone.

  • Compatible Moulds
  • Almost all Plastic moulds
  • Metal moulds
  • Condensation Cure Silicone moulds with a release agent
  • Compatible Pigments
  • RTV Silicone Colour Pigment (for vivid opaque colours)
  • Translucent Tinting Pigment (for less vivid opaque colours)

Key Processing Information

  • Ease of Use
  • Suitable for professional and hobby use (follow SDS advice).
  • Odour/b>
  • CS25 is almost odourless.
  • Safety Precautions/b>
  • Wear gloves and goggles and work in a well ventilated area. Always read the SDS before use.
  • >Ambient Conditions/b>
  • Can be used from 10 to 30°C although pot-life and cure time will be affected significantly.
  • Degassing/b>
  • Although CS25 will self degas, we recommend degassing for the best results.
  • Mix Ratio

    Mix silicone and Catalyst 100:5 by weight. Use digital scales.

  • Mixing/b>
  • Mix thoroughly by hand for at around 2 minutes.
  • Pot-Life/b>
  • 60-90 Minutes. Be sure to pour your casting(s) before this time.
  • Cure Time/Demould/b>
  • Demould Time 24 Hours @ 25°C

Pack Size

Easy Composites' CS25 Condensation Cure Silicone Rubber is available in the following pack sizes: 0.5kg, 1kg and 5kg. Please choose the pack size you require from the drop-down list. The 1kg kit is also included in the Xencast Resin Casting Starter Kit.

Downloads (2)

This is a chemical product. Before storage or use you must download and read the accompanying safety and technical datasheets.

Safety Datasheet (SDS)220 KB
Technical Datasheet (TDS)282 KB

Specification

Product Data
ColourGrey
Chemistry / MaterialRTV Silicone Rubber
Viscosity23000mPa.s
Pot Life (Typical)75mins
Initial Cure Time25Hrs
Cured Mechanical Properties
Max Service Temp250°C
Hardness25Shore A
Linear Shrinkage<1.0%
Tensile Strength4.0MPa
Elongation at Break525%
Tear Strength17.5kN/m
Weight and Dimensions
Density1.09g/cm³
General Properties
Gross Weight0.616kg
Can’t find the answer you’re looking for?Ask our technical team a question.

No, we do not have any additives that will reduce the viscosity. However, often despite the apparent high viscosity, the Silicones have very good flow properties and will flow into fine details and gaps much smaller than you would expect.

A thin smear of Vaseline (which can be thinned if necessary using methylated spirits) makes a good release agents between separate pours of RTV silicone.

Generally speaking, no, you do not need a release agent as really doesn’t stick to much at all. There are a couple of exceptions; firstly it sticks very well to itself and secondly it can stick (or at least ‘grip’) to porous materials. Porous materials and items with fragile surfaces should be sealed to prevent any sticking or damage during the moulding process. PVA, Shellac (sanding sealer) or paint/lacquer can all be used to seal the surface of porous materials. If in doubt, always test a small area first.

As long as the surface is free of dirt and contamination, then this silicone will stick to itself when you do the second pour. If the first pour of silicone has fully cured when you make the second pour then although it will bond and will become a single piece mould, the bond-line is likely to remain a weak-point.

If properly mixed and cured the cured silicone should be inert, none-reactive and none-toxic so there should be no reason why it would not be safe for skin contact however the product has not been specifically evaluated for medical use and so for commercial use in a medical application you might need to look further into whether any accreditation or independent testing is required.

The silicone itself can certainly be used on its own. When you buy the product you get the silicone and its catalyst together. Mix up as much (or as little) as you need and then pour them to create your cured rubber part. You can use the rubber to make a silicone mould (which you could then pour casting resin into) or to make rubber parts themselves (which would normally mean pouring the liquid rubber into a rigid mould).

Pretty much the only material silicone will stick to is other silicone, so a release agent is needed. A thin smear of Vaseline (which can be thinned using methylated spirits) or a spray wax called Macwax make effective release agents when you need to release silicone from silicone.

CS25 does not build up heat during the cure cycle.

Yes, silicone does stick to some kinds of Glass. You will need to use a release agent on Glass objects to aid the release of the silicone.

.

Yes, silicone does stick to porcelain. You will need to use a release agent on porcelain objects to aid the release of the silicone.

.

Yes, the mould can most certainly be used more than once. Exact lifespan depends on type of resin used, shape of the cast and other factors, but typically for most resins you would expect 10-15 pulls from the mould before it degrades and becomes unusable.

Yes you can use the CS25 for casting concrete into it. It is quite a flexible silicone so the mould will need to be supported to help stop flex and improve mould life. If you need a very long-life mould for casting concrete then an alternative would be our PX60 Flexible Polyurethane; this is often used for high production volume concrete moulds.

CS25 Condensation cure silicone has a working temperature range from -60°C up to 250°C.

Although we don't list the catalyst separately on the website (as all the packs come with the correct amount) we would be happy to supply the catalyst on it's own, please call or email our sales staff to arrange. 

At 20°C, 1kg of mixed Condensation cure silicone will have a volume of approximately 890cm³ (0.89 litres)

There is really no upper limit to the volume of the mould that you can create using our CS25 silicone rubber but from a practical perspective you are unlikely to want to mix much more than about 20kg at a time because any more would be physically difficult to mix and pour.

In the spec for the Addition Cure Silicone rubber the demould is 24 hours at room temperature but 2 hours at 60 degrees. In the spec of the CS25 Condensation Cure Silicon Rubber, it simply says demould in 24 hours. Is it safe to assume a similar 2/3 hours at 60 degrees?

No. Unlike addition cure silicone rubber, the cure speed of condensation cure silicone rubber (such as our CS25) is not increased with the addition of heat. Condensation cure reactions actually need some ambient moisture and so you will often find that using an oven to try to speed up the cure has the opposite effect and actually slows down the cure of condensation cure silicones.

Unfortunately not due the moisture content in condensation cure silicone's meaning it would likely make the resin cloudy and possibly not cure properly. A better alternative is an addition/platinum cure silicone such as our Addition Cure Silicone Rubber.

The only exception to this, is our range of GlassCast Clear Epoxy Casting Resins which have all been successfully tested and work well with our CS25 Condensation Cure Silicone.

No, we don't currently have a thixotropic additive for this Condensation Cure silicone rubber. We do have a Thixotropic Additive for our Addition Cure Silicone Rubber though; using these two products you would certainly be able to brush them onto a cornice, in position (even over your head) and take a mould of the detail quite easily.

No, our CS25 is opaque and grey once cured. If you need a translucent silicone then our Addition Cure Silicone Rubber is translucent once cured.

No, this is not 'food safe' or FDA approved silicone so it should not be used for food use. Furthermore, it's normally 'Addition Cure' silicone rubbers that are used for food applications (although we don't carry any food-safe silicone at this time)

ASK YOUR OWN QUESTION

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Customer Product Reviews for CS25 Condensation Cure Silicone Rubber

5/5 Average rating
10/9/2020
|
Dragi C.
|

The CS25 Silicone Rubber is a great product. It is very easy to work with and is very elastic. I recommend pouring a thick silicone mould as it is otherwise very flexible and bendy. I find that I don't have any issues demoulding resin parts once they are cured. I recommend the CS25 with a clear conscience.

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We publish all reviews for verified purchases. Submit your own review and help other customers with their choices.

Shipping Information

In the currently selected pack size, this product is classed as 'Limited Quantity Dangerous Goods' for the purposes of transport. This means that transport restrictions apply to certain destinations.

No restrictions or surcharges shipping by road to:

UK, Ireland, Channel Islands, Isle of Man, Austria, Belgium, France, Germany, Luxembourg, Monaco, Netherlands, Norway, Finland, , Czech Republic, Denmark, Hungary, Italy, Poland, Portugal, Spain, Andorra, Switzerland, Estonia, Latvia, Lithuania, Slovakia, Slovenia, Sweden

Shipping possible by airfreight (£55 surcharge applies) to:

United States, Finland, Bahrain, Hong Kong, Japan, Republic of Korea, Kuwait, Singapore, Taiwan, United Arab Emirates, Trinidad and Tobago

Can't ship to:

All other countries. If your country is not listed above then unfortunately we can't ship this product to you.

For very large orders, specialist shipping can be arranged. Please contact us to discuss.

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