mouldmaking rubber


Era Polymers is the master distributor for Dow Corning RTV Moldmaking Rubbers in Australia and New Zealand

Era Polymers are currently stocking most grades in the range at our Sydney warehousing facilities, making Dow Corning moldmaking rubbers easily accessible to the local Australian/New Zealand market.


Using silicone rubber products from Dow Corning you can easily and quickly make a mould of nearly any object, anywhere. Silicone rubber captures very fine detail for accurate reproduction. In its uncured liquid state, the silicone rubber material can be brushed and/or poured into a mould to replicates the original part with great detail.


After curing, the rubber mould is used to cast various materials into to make replications of the original part. Replications are often cast in many materials such as polyurethanes, other plastics, wax, concrete, plaster and low-melt point metals.

The self-releasing properties of the silicone mould’s surface allows for easy de-moulding and long mould life.


Dow Corning silicone mouldmaking rubbers are available in two types:

•   Condensation curing – Most popular, generally lower cost with shrinkage rate (~1%)

•   Addition curing – Premium materials with very low shrinkage rate (~0.1%)

Within each type there are various hardnesses available, and different quality levels.

Please select from the options below to learn more about the grades on offer.


Condensation cured products are characterised by high tear-strength and elasticity. Together with a very good flowability, this allows detailed reproduction of complex originals with deep undercuts, without harming the original. The multitude of possible combinations of base with curing agents and additives allows customising products for different purposes.


Condensation Cured

Product Hardness Tensile Strength (MPa) Elongation at break (%) Tear Strength (kN/m) Datasheet
Silastic 3481 21A 4.9 560 26 AU
Silastic 3110 45A 175 AU
Silastic 3120 60A 4.8 130 <5 AU
Silastic 3483 13A 3.5 600 25 AU
Silastic 3487 8A 2.6 650 13 AU


Addition cured products are characterised by extremely low shrinkage during curing, as well as by high temperature stability. These materials are therefore appropriate if a high dimensional accuracy is required of the replica. Addition cured silicones have the added ability of being able to speed up the cure through heating. This makes them suitable for rapid processing type environments.


Addition Cured

Product Hardness Tensile Strength (MPa) Elongation at break (%) Tear Strength (kN/m) Datasheet
Silastic E 37A 5.5 350 19 AU
Silastic J 56A 5.5 250 15 AU
Silastic S 25A 7.0 850 23 AU
Silastic S-2 20A 6.3 600 23 AU
Silastic T-4 40A 6.7 400 27 AU



Adding 1-3% of this additive to some of the Dow Corning silicones will give them a paste-like consistency. Typically added to the silicone to make a paste which is used to brush/spatula on an initial layer of silicone to pick up the most detailed replications of the original. After applying this initial brushed layer, the standard silicone is used (with no Thixo additive) to pour on the bulk layer of silicone.



DOW CORNING 200 FLUID – 50cst and 100cst.  This product can be used as a thinner to lower mixed viscosity and also adjust the hardness of the cured silicone. It can also be used as a release agent. Users must conduct their own trials to establish the optimum silicone oil viscosity and amount.



Dow Corning 1200 Prime Coat is used to promote adhesion of silicone to a variety of construction materials such as plywood, masonry and metal.