Wacker Elastosil® RT 625 A/B – Pourable Addition Silicone for Molds & Encapsulation
Wacker Elastosil® RT 625 A/B – Pourable Addition Silicone for Molds & Encapsulation
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Premium Pourable Addition Curing Silicone for Professional Mould Making and Encapsulation Applications
Wacker ELASTOSIL® RT 625 A/B is a pourable, addition-curing 2-component silicone rubber that cures at room temperature with a Shore A hardness of 25, fully translucent end product, and excellent mechanical properties. With a pot life of 60 minutes and a curing time of 12 hours at 20°C, this product offers ample processing time for complex moulds without time pressure. The mixing ratio is 9:1 (A:B) by weight, with the platinum catalyst in component B. ELASTOSIL RT 625 is ideally suited for applications where low viscosity, high tear strength, and shrink-free curing are essential.
Key Benefits
- Low viscosity (12,000 mPa·s): Flows effortlessly into complex shapes and narrow cavities without air bubbles – ideal for detailed moulds
- Shrink-free curing: Linear shrinkage < 0.1% for dimensionally accurate reproductions and repeated casting
- Excellent tear strength (30 N/mm): Moulds release easily without tearing, even with complex undercuts
- High elongation (600%): Particularly flexible and robust when demoulding moulds with fine details
- Curing in closed systems: Addition curing does not require atmospheric moisture – suitable for encapsulation
Typical Applications
- Mould making for casting polyurethane, epoxy, plaster, and acrylic resin in art, design, and prototyping
- Encapsulation of electrical and electronic components for protection and electrical insulation
- Coatings and protective layers for technical parts and delicate objects
- Reproduction of moulds for vacuum bags in composite processing
- Production of technical cast parts in small and medium series
Processing Instructions:
- Stir components A and B thoroughly and separately before use
- Mix A and B in a 9:1 weight ratio — use only components with the same batch number
- Mix slowly and carefully to minimise air entrapment
- Optional: vacuum immediately after mixing to remove residual air bubbles
- Pour within the 60-minute pot life
- Allow to cure for 12 hours at 20°C — accelerated curing is possible by increasing the temperature
Wacker Chemie AG is a global market leader in the development and production of silicones for industrial and technical applications. The ELASTOSIL series is known for consistent quality and reliable technical specifications.
Important Warning: Inhibition in Addition-Curing Silicones
Please note: This is an addition-curing silicone (platinum-cure). These silicones can be inhibited by sulphur, nitrogen, amino compounds, and metal salts. If you are unsure whether the materials you are using (gloves, spatulas, moulds) contain these substances, first do a small test. Inhibiting substances can be found in latex gloves, some plasticines, condensation-curing silicones, 1-component silicone sealant, and certain 3D printing materials. If in doubt, apply a layer of polyvinyl alcohol (PVA) as a release agent.
Professional Support
Our technical specialists advise on processing techniques, vacuum degassing, curing acceleration, and the right choice for your specific mould-making, encapsulation, or coating application. Contact us for technical datasheets, processing manuals, or product advice.
Product Properties
- Hardness25Shore AHardness of the silicone material
- Shrinkage0.1%Linear shrinkage after curing
- ColorTranslucentColor of the finished product
- TransparencyTranslucentDegree of transparency
- Viscosity12000mPa·sViscosity of the uncured silicone
- Density1.1g/cm³Density of the cured material
- Mix ratio9:1Mixing ratio A : B
- Tensile strength6.5MPaMaximum tensile force before breaking
- Tear strength30.0kN/mResistance against tearing
- Elongation at break600%Maximum stretch before breaking
- Pot life60minutesWorking time after mixing
- Cure time720minutesTime until full cure
Component Properties
- Color ATranslucentColor of component A
- Color BColorlessColor of component B
- Viscosity A25000mPa·sViscosity of component A
- Viscosity B900mPa·sViscosity of component B
- Density A1.1g/cm³Density of component A
- Density B0.98g/cm³Density of component B
Electrical Properties
- Electrically insulatingYesPrevents electric current flow
Certification & Safety
- Moisture resistantYesResistant to moisture and water absorption
Application
- Use caseMould making, encapsulation, coating, technical castingsIntended use
- Silicone type["Addition curing","RTV-2"]Type of silicone or polymer
- Cure speedNormalHow quickly the material can be demoulded
- Cure conditionRoom temperatureCondition under which the material cures
Safety Information
ELASTOSIL RT 625 A/B is not classified as a hazardous substance under normal use. Component A contains silica in nanoform (CAS 68909-20-6) which can cause damage to the lungs through repeated inhalation exposure (H373), but under normal processing conditions, these particles remain bound within the product and do not pose an inhalation risk. When processing, wear nitrile or butyl rubber gloves and safety glasses. Respiratory protection is not required under normal use, but is recommended for atomisation or spray work. Consult the full Safety Data Sheets (SDS) for comprehensive information on storage, disposal, and emergency measures.| Safety Pictograms | Safety Data Sheets (SDS) |
|---|---|
GHS hazard pictograms
Required protection (ISO 7010)
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Frequently asked questions
What is the delivery time for my order?
Orders placed and paid on working days are in most cases shipped the same day. Weekend orders are processed on the next working day.
Indicative delivery times: Netherlands usually within 1 working day, Belgium and Germany typically 1–2 working days, other countries depending on destination and carrier. These are guidelines, not guarantees: peak periods, public holidays or carrier delays can have an effect.
What is the return policy?
You have 30 days to return after receipt. Email info@siliconesandmore.com within 30 days of delivery with your name and order number. The full conditions are in our return policy.
How can I track my order?
As soon as your order has shipped, you'll receive a track & trace code by email. It can take up to 24 hours before the code is active.
I have a problem with my order – how do I reach you?
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Can I order as a business?
Yes. Apply for a business account; we review your application within 3 working days. After that you order while logged in and pay on invoice, with payment terms of 14 days after delivery.
EU businesses outside the Netherlands with a valid VAT number order with VAT reverse-charged (0%, intra-community supply). The VAT number is stored in your business account; it cannot be added to an order after it has been placed.