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Curing Agent 81 F
201084050
€6.00
7,26 € Tax incl.
7,26 € Tax incl.
Fast curing agent for Silastic 3481 and 3483 silicones. Use ratio 5%. Working time 90 min, demould in 6 h.
Curing Agent 81 F is a fast-curing condensation catalyst designed to accelerate the vulcanisation process of tin silicones such as Silastic 3481 and Silastic 3483. With just a 5% addition you get a comfortable working time of 90 minutes and demoulding in only 6 hours, ideal for workshops that need to speed up production cycles without giving up process control.
Technical specifications
| Parameter | Value |
|---|---|
| Catalyst type | Condensation (tin) |
| Use ratio | 5% by weight of base silicone |
| Working time | 90 minutes |
| Demould time | 6 hours |
| Compatibility | Silastic 3481, Silastic 3483 |
| Relative speed | Fast (F = Fast) |
What it is used for
Curing Agent 81 F is used in all processes involving Silastic condensation silicones where the total cycle time needs to be reduced compared to standard catalysts. It is especially useful in serial production, where reducing demould time has a direct impact on workshop profitability.
- Manufacturing silicone moulds for casting resins, plaster and wax
- Serial production of silicone parts with tight cycle times
- Moulding for special effects, prosthetics and character make-up
- Sculpture replicas, crafts and artistic reproductions
- Industrial applications with Silastic casting silicones
How to use it
- Prepare the base silicone (Silastic 3481 or Silastic 3483) and weigh it accurately.
- Calculate 5% of the total weight of base silicone: that is the amount of Curing Agent 81 F you need to add.
- Add the catalyst to the base silicone and mix thoroughly for at least 2–3 minutes, scraping the sides and bottom of the container carefully.
- If you need to apply the mixture to vertical surfaces or mould ceilings, you can add the Thixo Additive Aditivo Tixotrópico para Siliconas before catalysing, without affecting cure time.
- Pour or apply the silicone onto the model within the 90-minute working time available.
- Allow to cure at room temperature. After 6 hours you can safely demould.
- To facilitate demoulding of the original model, apply a release agent paste for silicones beforehand.
Usage tips
Always weigh, never measure by volume
The 5% catalyst must be calculated by weight, not by volume. A precision scale with at least 0.1 g resolution is essential for reproducible results. An incorrect ratio can result in soft, sticky moulds or incomplete curing at the core.
Temperature affects working time
The 90-minute working time is referenced at standard room temperature (approximately 23 °C). In summer or in warm workshops, the catalyst can noticeably accelerate curing. If you need more pot life, work in a cooler environment or consider using slightly less catalyst, always within the recommended range. If you need even faster curing, the Curing Agent 81 VF is available with an even faster cure.
Homogeneous mixing for uniform cure
Any area with insufficient catalyst will remain uncured. Always mix with slow, deliberate movements to avoid incorporating air bubbles, and scrape the sides and bottom of the container thoroughly. If you have a vacuum chamber, degassing the mixture before pouring significantly improves the surface quality of the mould.
Frequently asked questions
How much catalyst should I add?
Curing Agent 81 F is used at 5% by weight of the base silicone. For example, for 1000 g of Silastic, you need 50 g of catalyst. Do not vary this ratio significantly: adding less can leave areas uncured, and adding more does not usefully speed up the process.
Can I use this catalyst with any silicone?
Curing Agent 81 F is specifically formulated for the Silastic 3481 and Silastic 3483 condensation silicones. It is not suitable for platinum (addition) silicones or for any other silicone bases outside these references.
How does it differ from Curing Agent 81 VF?
The Curing Agent 81 VF is the very fast-curing catalyst (VF = Very Fast) from the same family. It offers even shorter demould times, which is useful when production throughput is very high. The 81 F gives you 90 minutes of working time, making it more suitable for complex mouldings that require more handling time.
Does the thixotropic additive affect cure time?
No. The Thixo Additive modifies the rheology of the silicone to make it thicker and prevent it from sagging on vertical surfaces, but it does not affect working time or demould time. Curing proceeds exactly the same as without it.
Do I need a release agent when using this silicone on plaster or wood models?
It depends on the model material. Porous materials such as plaster, wood or gypsum always require a release agent to prevent the silicone from penetrating the pores and sticking. Ferosil V 32 is a release agent paste specifically for silicones that seals the pores and facilitates demoulding without damaging the original model.
How long does it take to fully cure if the workshop temperature is high?
Ambient temperature accelerates the curing of condensation silicones. In warm environments, working time can be significantly reduced from the reference 90 minutes. Work within the first 60 minutes if your workshop exceeds 25–28 °C, and keep materials cool before mixing.
Can I combine this catalyst with pigments to colour the silicone?
Yes, as long as the pigments are compatible with condensation silicones. Add the pigment to the base silicone before incorporating the catalyst, mix thoroughly, then catalyse. Make sure the pigments do not contain any components that interfere with condensation curing.
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