CS25 Condensation Cure Silicone Rubber

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Downloads (3)

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

	Safety Datasheet (SDS)	700 KB
	Dutch Safety Datasheet	753 KB
	Technical Datasheet (TDS)	282 KB

Specification

Product Data

Colour	Grey
Chemistry / Material	RTV Silicone Rubber
Viscosity	23000	mPa.s
Pot Life (Typical)	75	mins
Initial Cure Time	25	Hrs
Shelf Life	6	Months

Cured Mechanical Properties

Max Service Temp	250	°C
Hardness	25	Shore A
Linear Shrinkage	under 1	%
Tensile Strength	4.0	MPa
Elongation at Break	525	%
Tear Strength	17.5	kN/m

Weight and Dimensions

Density	1.09	g/cm³

General Properties

Gross Weight	0.616	kg

Shipping Information

Restrictions

This product is classed as dangerous goods for transport.

It can be shipped to all mainland EU countries, Ireland, Balearic Islands, Corsica, Sicily and Sardinia.

Unfortunately, for the time being we are unable to ship dangerous goods to Cyprus, Malta, the Canary Islands, Ceuta, Melilla, Jan Mayan and Svalbard.

For a full information regarding the shipment of dangerous goods, see our delivery information page.

Package Size

There are no package size restrictions or surcharges for this product.

Delivery Cost

To find the delivery cost of this item to your address, add it to your basket and then use the instant shipping calculator on the basket page.

PRODUCT VIDEOS(3)

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 mold can then be used to produce precise replicas of the original part, including fine surface detail. A range of materials are suitable to use, 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: CS25 is almost odourless.
Safety Precautions: Wear gloves and goggles and work in a well ventilated area. Always read the SDS before use.
Ambient Conditions: Can be used from 10 to 30°C although pot-life and cure time will be affected significantly.
Degassing: 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: Mix thoroughly by hand for at around 2 minutes.
Pot-Life: 60-90 Minutes. Be sure to pour your casting(s) before this time.
Cure Time/Demould: Demould Time 24 Hours @ 25°C
Shelf Life: 6 Months

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 (3)

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

	Safety Datasheet (SDS)	700 KB
	Dutch Safety Datasheet	753 KB
	Technical Datasheet (TDS)	282 KB

Specification

Product Data

Colour	Grey
Chemistry / Material	RTV Silicone Rubber
Viscosity	23000	mPa.s
Pot Life (Typical)	75	mins
Initial Cure Time	25	Hrs
Shelf Life	6	Months

Cured Mechanical Properties

Max Service Temp	250	°C
Hardness	25	Shore A
Linear Shrinkage	under 1	%
Tensile Strength	4.0	MPa
Elongation at Break	525	%
Tear Strength	17.5	kN/m

Weight and Dimensions

Density	1.09	g/cm³

General Properties

Gross Weight	0.616	kg

Can’t find the answer you’re looking for?Ask our technical team a question.

Yes, unfortunately both polyurethane and to a greater extent, epoxy resins do 'dry out' silicone over time. To be perfectly honest we would consider that after 30 or so pulls form a silicone mould it would be nearing the end of its life anyway, so it's not bad going. You can extend the life of the silicone by occasionally treating the surface with silicone oil. This rejuvenates the surface somewhat and can usually extend the life of the tool and prevent parts from sticking.

For metal casting at home, most people tend to use special 'low melting point' metal alloys, rather than regular lead. The reason for this is that regular lead has a melting point of 327°C which is too high for any type of moulding silicone rubber. Special 'casting alloys' tend to be a tin/antimony/lead alloy and have a melting point around 190°C and a recommended pouring tempertaure of around 240°C which is much more suitable for casting into silicones, which tend to have maximum service temperatures of around 250°C, including both our CS25 and AS40 silicones.

In terms of a recommended silicone, both CS25 and our AS40 can be used as moulds for metal casting if you're using a casting alloy that can be cast at 250°C or less. If you were using regular tin then I'd steer clear of silicones altogether, none of them can reliably be used for the 350°C pouring tempertaures you would need for lead. Out of the two, CS25 is lower cost and easier to use but it will deteriorate faster than AS40 so it would be the best option for smaller numbers (say less than 20) but if you want to make large quantities of the castings then AS40 would be better.

Metal won't stick to silicone so you wouldn't need any sort of release agent or any other products in order to start casting pieces like small soldiers using a low-melt casting alloy.

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.

I would definitely recommend testing a small sample first, but CS25 is pretty inert so unlikely to effect the foam in any way.

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

Shipping Information

Restrictions

This product is classed as dangerous goods for transport.

It can be shipped to all mainland EU countries, Ireland, Balearic Islands, Corsica, Sicily and Sardinia.

Unfortunately, for the time being we are unable to ship dangerous goods to Cyprus, Malta, the Canary Islands, Ceuta, Melilla, Jan Mayan and Svalbard.

For a full information regarding the shipment of dangerous goods, see our delivery information page.

Package Size

There are no package size restrictions or surcharges for this product.

Delivery Cost

To find the delivery cost of this item to your address, add it to your basket and then use the instant shipping calculator on the basket page.

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Downloads (3)

Specification

Product Data

Cured Mechanical Properties

Weight and Dimensions

General Properties

Shipping Information

Restrictions

Package Size

Delivery Cost

CS25 Condensation Cure Silicone Rubber

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Downloads (3)

Specification

Product Data

Cured Mechanical Properties

Weight and Dimensions

General Properties

ASK YOUR OWN QUESTION

Customer Product Reviews for CS25 Condensation Cure Silicone Rubber

SUBMIT YOUR OWN PRODUCT REVIEW

SUBMIT YOUR OWN PRODUCT REVIEW

Shipping Information

Restrictions

Package Size

Delivery Cost

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