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Curing Agent 81 VF
201085050
€6.00
7,26 € Tax incl.
7,26 € Tax incl.
Fast-acting curing agent for Silastic silicones. 5% dosage, 10 min working time and demoulding in 90 min.
Curing Agent 81 VF is a fast-acting catalyst designed for condensation silicones such as Silastic 3481 and 3483. Its VF (Very Fast) formulation drastically reduces workshop cycle times, allowing demoulding in just 90 minutes with a minimum dosage of 5%.
Technical specifications
| Parameter | Value |
|---|---|
| Recommended dosage | 5% by total weight of silicone |
| Working time (pot life) | 10 minutes |
| Demould time | 90 minutes |
| Cure type | Condensation (tin) |
| Compatibility | Silastic 3481, Silastic 3483 |
What it is used for
This curing agent is indicated when production cycle times need to be reduced, or when workshop conditions (low temperature, reduced humidity) slow down the cure of the base silicone. It is the most suitable option for:
- Series production moulding where demould time is critical
- Workshop jobs at low ambient temperatures
- Quick silicone castings for prototypes or masters
- Applications where the thixotropic additive is combined with the silicone for layer application or vertical surfaces
- Special effects and character work where tight cycle times are required
How to use it
- Prepare the master or model and apply a paste release agent for silicones if the surface requires it.
- Weigh out the base silicone (Silastic 3481 or 3483) in the required amount.
- Calculate 5% of the total silicone weight to determine the amount of Curing Agent 81 VF needed.
- Add the curing agent to the silicone and mix thoroughly for at least 2 minutes, scraping the sides and bottom of the container well.
- If you are using thixotropic additive, incorporate it before the catalyst or according to your formulation protocol.
- Pour or apply the mixture onto the model within the next 10 minutes (maximum working time).
- Allow to cure without moving the mould. At normal ambient temperature, demoulding is possible after 90 minutes.
Usage tips
Respect the working time
With only 10 minutes of pot life, prior preparation is essential. Have the model ready, the release agent applied, and the mixing container prepared before adding the catalyst. Once mixed, the silicone begins to gel quickly and any delay can ruin the casting.
Temperature affects the cure
Condensation silicones cure more slowly at low temperatures and faster with heat. If you are working below 18 °C, the demould time may exceed the stated 90 minutes. Above 25 °C, the process may accelerate and further reduce the available pot life. Adjust your timing according to the actual conditions in your workshop.
Precise dosage
Use a precision scale to calculate the 5% catalyst amount. An excess does not significantly accelerate the cure but may affect the final properties of the elastomer. Too little can result in incomplete cure or a tacky silicone. If you need a slightly longer working time, consider Curing Agent 83, which has a slower action.
Frequently asked questions
Can I adjust the amount of catalyst to get more working time?
Reducing the dosage below 5% to gain working time is not recommended. Doing so may result in incomplete cure or a silicone with poor mechanical properties. If you need more working time, use Curing Agent 83, which offers a wider pot life while maintaining a correct cure.
Does the thixotropic additive change the cure time?
No. The thixotropic additive only modifies the viscosity and rheological behaviour of the silicone; it does not interfere with the curing reaction. The working and demould times of Curing Agent 81 VF remain the same with or without thixotropic additive.
Which silicones is this catalyst compatible with?
Curing Agent 81 VF is formulated specifically for condensation silicones Silastic 3481 and Silastic 3483. It must not be used with platinum (addition) silicones or other elastomer families without confirming compatibility beforehand.
What happens if the mould does not cure properly or remains tacky?
Poor cure is usually caused by insufficient catalyst dosage, incomplete mixing, or working temperatures that are too low. Check that you have correctly weighed out the 5% catalyst and that the mixture has been thoroughly homogenised for at least 2 minutes. If the problem persists in cold conditions, gently warm the area around the mould to promote the reaction.
Do I need to apply a release agent before casting the silicone?
It depends on the master material. Condensation silicones do not adhere to most porous or semi-porous surfaces, but on plastics, resins, or smooth surfaces it may be advisable to apply a paste release agent for silicones to ensure a clean release and protect the master.
Can I use this catalyst with silicone oil to reduce hardness?
Fluido DC 50 (silicone oil) can be added to the base silicone to reduce the viscosity or hardness of the final elastomer. However, its addition may affect the mechanical properties and the cure. Run preliminary tests with small amounts before using it in production.
How long can I store the catalyst without it losing effectiveness?
Store Curing Agent 81 VF in its original tightly closed container, in a cool place away from direct sunlight. Under proper storage conditions, it retains its properties for the period indicated on the packaging. Avoid contaminating the product with residues of already-catalysed silicone.
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