Wacker Catalyst T 37® – Hardener for ELASTOSIL® M Condensation Silicones & Mold Making
Wacker Catalyst T 37® – Hardener for ELASTOSIL® M Condensation Silicones & Mold Making
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Premium Tin Catalyst Hardener for Professional Condensation Silicone and Mold Making Applications
Wacker® Catalyst T 37 is the standard hardener (B-component) for condensation-curing ELASTOSIL® M silicone rubbers, including M 4400, M 4440, and M 4470. It is a colorless, low-viscosity tin catalyst with a density of 0.94 g/cm³ and a viscosity of approximately 2 mPa·s. T 37 is distinguished by the excellent resistance it imparts to the cured silicone against polyurethane casting resins, increasing the number of castings per mold. The standard dosage is 3 to 4% by weight of the A-component: at 3%, you achieve a working time of approximately 80–100 minutes and a curing time of 10–12 hours; at 4%, this shortens to 50–70 minutes working time and 8–10 hours curing time. Less hardener prolongs the curing time and gives air bubbles more time to escape; more hardener accelerates curing but increases shrinkage and aging of the mold.
Key Benefits
- Dosage 3–4% by weight – precisely adjustable working and curing time as desired.
- Density 0.94 g/cm³ – low-viscosity catalyst (approx. 2 mPa·s) that can be easily and uniformly mixed in.
- Pot life 80–100 minutes at 3% – ample working time for large and complex molds.
- High polyurethane resistance – significantly increases the number of castings with polyurethane casting resins.
- Flash point 70 °C – for safe processing under normal workshop conditions.
- Mixable with fast catalyst – can be combined with T 47 to further accelerate the curing speed.
Typical Applications
- Hardener for ELASTOSIL® M 4400, M 4440, and M 4470 condensation silicones.
- Mold making for casting polyurethane and polyester resins.
- Reproduction of statues, ornaments, and decorative elements.
- Art casting, model making, and prop and set construction.
- Mixing with other Wacker T-catalysts for a desired curing speed.
Processing Instructions
- Stir the condensation silicone (A-component) thoroughly in its packaging before use.
- Weigh out Catalyst T 37 by weight: 3 to 4 grams per 100 grams of A-component. Less hardener prolongs curing time, more hardener accelerates it but increases shrinkage.
- Mix A and B components slowly and thoroughly until a homogeneous mixture is achieved; scrape the sides and bottom of the mixing container.
- Process the mixture within the pot life and never prepare more than you can process within that time.
- Allow the silicone to fully cure according to the specifications of the chosen ELASTOSIL® M product before demolding.
Please note: pot life and curing time are highly dependent on the mixing ratio and humidity. With more hardener or higher humidity, both will be shorter.
Wacker Chemie AG is a world market leader in the development and production of silicones for industrial and technical applications.
Professional Support
Not sure which catalyst or dosage is right for your silicone and desired processing time? Our specialists will gladly advise you on the correct choice and possible combinations with other Wacker T-catalysts. Feel free to contact us.
Certification & Safety
- Chemical resistanceIncreases the resistance of the mould to polyurethane and polyester resinsResistance to chemicals
Application
- Use caseHardener for ELASTOSIL M condensation siliconesIntended use
- Silicone type["Auxiliary material"]Type of silicone or polymer
- Cure conditionRoom temperatureCondition under which the material cures
Safety Information
Wacker Catalyst T 37 is classified as hazardous (GHS08, health hazard) and contains an organotin compound. The relevant hazard statements are H373 (may cause damage to organs through prolonged or repeated exposure) and H413 (may cause long-lasting harmful effects to aquatic life). Avoid breathing vapor or spray and prevent release to the environment. The product is flammable with a flash point of approximately 70 degrees Celsius; keep it away from heat and ignition sources. When processing, wear suitable protective gloves made of butyl rubber, close-fitting safety glasses (EN 166), and protective clothing. Ensure good ventilation and extraction. When atomizing or forming aerosols, use a respiratory mask with an ABEK or ABEK-P2 filter. Do not eat, drink, or smoke while working, and wash hands thoroughly after use. For complete information, always consult the Safety Data Sheet (SDS) for Wacker Catalyst T 37.| Safety Pictograms | Safety Data Sheets (SDS) |
|---|---|
GHS hazard pictograms
Required protection (ISO 7010)
     |
| Signal Word | H‑code | Hazard Statement | P‑codes | P‑statements |
|---|---|---|---|---|
| Warning | H373 | May cause damage to organs through prolonged or repeated exposure | P260 P501 |
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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?
Contact us via our contact page or email info@siliconesandmore.com. We're happy to help you quickly.
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.