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PlatSil Hardener Part H -Silicone Hardener-
590102002
€30.00
36,30 € Tax incl.
36,30 € Tax incl.
Hardener for PlatSil Gel series platinum silicones. Increases Shore Hardness and working time. Max ratio 1A:1B:1H.
PlatSil Hardener Part H is a dedicated hardener for platinum silicones in the PlatSil Gel series that lets you increase the Shore Hardness of the resulting material without sacrificing flowability or ease of processing. Added in the correct ratio, it produces stiffer, dimensionally stable moulds from low-hardness silicones while also extending working time and demould time.
Technical specifications
| Parameter | Value |
|---|---|
| Material type | Hardener for platinum silicone (addition cure) |
| Compatibility | PlatSil Gel series (Gel OO, Gel 10, Gel 25…) |
| Maximum use ratio | 1A : 1B : 1H (never exceed) |
| Effect on PlatSil Gel OO (1A:1B:1H) | Hardness equivalent to PlatSil Gel 10 |
| Effect on PlatSil Gel 10 (1A:1B:1H) | Shore Hardness A20 |
| Effect on PlatSil Gel 25 (1A:1B:1H) | Shore Hardness A40 / working time 7 min / demould 2 h |
What it is used for
PlatSil Hardener Part H is designed for professionals who need to fine-tune the final hardness of their silicone moulds without switching base products. By starting from a low-hardness silicone, you retain flowability and ease of mixing while reaching the Shore you need.
- High dimensional-precision block mould fabrication with PlatSil Gel 25.
- Flat moulds for silicone prosthetics that do not distort when a spatula is applied.
- Achieving intermediate or higher hardnesses without resorting to higher base-Shore silicones (which are more viscous and harder to degas).
- Adjusting working time and demould time in productions where casting pace demands it.
- Special effects and facial prosthetics where a specific balance between flexibility and rigidity is required.
How to use it
- Prepare your PlatSil Gel silicone as usual by weighing Parts A and B in the ratio specified by the manufacturer (normally 1A:1B).
- Add Part H in the same amount by weight as Part A (ratio 1A:1B:1H). Never exceed this ratio.
- Mix the three components thoroughly, scraping the sides and bottom of the container carefully.
- If you need higher viscosity for vertical applications or curved surfaces, add Thixo Additive at this stage in the recommended ratio.
- Apply or pour the mixture onto the model, previously treated with a Release agent if the substrate requires it.
- Observe the working time indicated (for Gel 25 with H: 7 minutes) and do not handle the mould until the demould time is complete (2 hours in that case).
- Demould carefully and allow the mould to rest for at least 24 hours before using it in production to ensure full cure.
Important notice — Platinum silicone inhibition: Platinum (addition cure) silicones are extremely sensitive to inhibition caused by contact with certain materials. If any of these materials comes into contact with uncured silicone, the cure may be partially or completely blocked:
- Plasticines or clays containing sulphur.
- Latex and rubber-derived products.
- Cyanoacrylate adhesives and their vapours.
- Uncured epoxy resins.
- Some tin catalysts (condensation cure).
- Vinyl gloves and some types of latex gloves.
Tips for use
Do not exceed the 1A:1B:1H ratio
The maximum ratio is strict: adding more Part H than indicated does not increase hardness proportionally and may cause poor cure or a silicone with degraded mechanical properties. If you need a very high Shore Hardness from the outset, consider using a higher base-Shore silicone rather than forcing the amount of hardener.
Take advantage of the low starting viscosity
One of the main advantages of using PlatSil Hardener together with low-hardness silicones (such as Gel OO or Gel 10) is that you retain the flowability of the original product during mixing and pouring. This makes capturing fine details and eliminating bubbles considerably easier, especially when working without a vacuum chamber. If you also need the silicone not to drip when applied on inclined surfaces, add Thixo Additive to increase thixotropy without affecting the cure.
Manage working time properly
PlatSil Hardener extends the working time compared to the base silicone without hardener, which can be an advantage on complex projects. However, if you ever need to accelerate the overall cure of the system, you can combine it with the Curing Agent 81 VF, but always run preliminary tests to verify the behaviour of the complete mixture before applying it in production.
Frequently asked questions
Can I use this hardener with any platinum silicone?
PlatSil Hardener Part H is formulated specifically for the PlatSil Gel series (Gel OO, Gel 10, Gel 25 and variants within the same family). Its compatibility and behaviour with other platinum silicones of different formulations is not guaranteed. Use it only with PlatSil Gel series products.
What happens if I add more hardener than the maximum indicated?
Exceeding the 1A:1B:1H ratio can cause incomplete cure, loss of mechanical properties, or a silicone with poor appearance and behaviour. The maximum ratio is a technical limit, not a guideline recommendation. If you need hardnesses beyond what the system with H can deliver, the right approach is to switch to a higher base-Shore silicone.
How much does working time increase when the hardener is added?
The increase depends on the base silicone used. In the case of PlatSil Gel 25 at the 1A:1B:1H ratio, working time is approximately 7 minutes and demould time is around 2 hours. Consult the specific data for each base silicone to estimate the effect accurately.
Does the hardener affect the transparency or colour of the silicone?
Under normal conditions, Part H does not significantly alter the visual appearance of the cured silicone. PlatSil Gel silicones retain their characteristic translucency. If you pigment the mixture with compatible colorants, the final result should not be affected by the hardener.
Can I use a thixotropic agent together with the hardener?
Yes. You can add Thixo Additive to the mixture to increase viscosity without affecting cure time. The thixotropic agent acts exclusively on the rheology of the material, not on the cure reaction, making it fully compatible with the use of Part H.
Is a release agent necessary when the mould is made with this silicone?
It depends on the material you are casting onto. Platinum silicones generally do not adhere to most substrates, but on porous models, plaster, wood or certain polymers it may be advisable to apply Ferosil V 32 to ensure clean demoulding and extend the service life of the mould.
What advantage does using this silicone with hardener have over using a Shore 40 silicone directly?
Starting from a low-hardness silicone and adding PlatSil Hardener gives you a much more fluid material during mixing and application. A pure Shore 40 silicone is more viscous, harder to degas and has longer demould times. With the hardener, you work with the flowability of Gel 25 and achieve the hardness of a Shore A40 with better process times.
Can I accelerate the cure of the system when using the hardener?
It is possible to combine Part H with the Curing Agent 81 VF to reduce cure times. However, before applying it in production, always run small-scale tests to verify that the behaviour of the complete mixture is as expected.
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