1. Mixing of the additive

These instructions refer to the addition of BLUESIL ACC PA 39 exclusively to a polyaddition RTV-2 silicone. There are two possibilities to incorporate the additive into a RTV-2 silicone, i.e. by adding it either to the A + B mixture or to a single part before mixing.
a) Adding BLUESIL ACC PA 39 to mixed A+B parts:
Mix together part A and part B of the BLUESIL RTV product according to the correct mixing ratio (usually ratio 1:1 or 10:1) as indicated in the product datasheet. Add 0.05 ÷ 1.00 parts by weight of BLUESIL ACC PA 39 and mix thoroughly.
b) Adding BLUESIL ACC PA 39 to one part before mixing:
The BLUESIL ACC PA 39 must be added exclusively to BLUESIL RTV part that contains the Platinum catalyst. Please refer to the MSDS of the RTV product to identify which part contains the catalyst.

Add BLUESIL ACC PA 39 with respect to the mixing ratio of A and B parts as follows:

  • catalyst part : base part = 1 : 1 => 0.05 ÷ 2.00 parts by weight of BLUESIL ACC PA 39
  • catalyst part : base part = 10 : 1 => 0.05 ÷ 1.00 parts by weight of BLUESIL ACC PA 39
  • catalyst part : base part = 1 : 10 => 0.5 ÷ 10.0 parts by weight of BLUESIL ACC PA 39

The additive should be well incorporated into the RTV by hand or by a mechanical mixer. Mix until perfect dispersion of the additive into the silicone.
Please note that the above mentioned addition levels are purely indicative and preliminary trials should be carried out in order to identify the correct level of BLUESIL ACC PA 39 needed by the process in use.
By exceeding the suggested maximum amount of BLUESIL ACC PA 39 of 1.0 parts by weight, change in final hardness could take place.

2. Degassing

The degassing of a RTV-2 silicone just before casting is recommended to eliminate the entrapped air introduced when mixing the two parts and BLUESIL ACC PA 39.
This is the procedure for a correct degassing:
The catalysed product is degassed under a 30 to 50 mbar vacuum. When the vacuum is applied the product expands 3-4 times its initial volume and bubbles form on the surface. Once bubbles disappears the mixture collapses back to its initial volume. To complete degassing simply wait few minutes before releasing the vacuum, then the product will then be ready to use.
Remark: pull and release the vacuum several times improves the degassing. For easier degassing only fill a recipient only to 1/3 of its height.

3. How to use

Apply the accelerated BLUESIL RTV according to the process need (e.g. casting, brush, etc...). If the added level of BLUESIL ACC PA 39 is rather high (e.g. 1%), the kinetic may be so fast that hand application of the product may be not feasible due to the accelerated vulcanization. This depends in any case on the kinetic of the original RTV-2 product at .
Remarks: Before using BLUESIL ACC PA 39 with a given BLUESIL RTV, please refer to the Safety Data Sheet of the RTV product to check in which of the two parts (A or B) the Platinum catalyst is contained.
BLUESIL ACC PA 39 does not work with the polycondensation range.


BLUESIL ACC PA 39 may be stored at temperatures between 2°C / 36°F and 40°C / 104°F for up to 24 months from its date of manufacturing.Please consult the Safety Data Sheet of this product.


BLUESIL ACC PA 39 is an additive that reduces the reaction time of those RTV-2 silicone elastomers that cure by a polyaddition reaction. Both the working time (i.e. the time until the product can be processed, also called pot-life or open-time) and the tack-free time (i.e. the time to achieve the final elastomeric properties, also called setting or curing time) will be shortened by the addition of BLUESIL ACC PA 39.


2 Part RTV

  • Easy and fast processing
  • High efficiency
  • Avoiding changes of process temperature to meet desired reaction time
  • Process flexibility (different reaction times obtainable with same RTV-2 elastomer)

Typical target of BLUESIL ACC PA 39 are the cases where the working and curing time of a RTV-2 polyaddition silicone are too long for the process conditions in use. For example, in cases where process temperatures are below or where higher productivity is desired.

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ColorYellow / ColourlessMonocomp