How to use the tin cure silicone for mold making?
Time:2024-01-20
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1. Mixing of the two components
To 100 parts of silicone base add 2~3 parts of the selected catalyst.
The two components are thoroughly mixed either using an electrical or pneumatic mixer on a low speed setting so as to limit the inclusion of air in the mixture as well as temperature rise.
2. Degassing
After mixing base and catalyst, it is recommended to degas to eliminate entrapped air.
If the processing is done with the help of a machine both parts are degassed before mixing.
It is degassed under vacuum pressure of 30 to 50 mbar. Under vacuum pressure, the product will expand 3 at 4 times its initial volume and forms bubble on its surface.
This bubble will disappear gradually and the mixture will sink back down to its initial volume within 5 to 10 minutes. Release the vacuum and repeat the operation a few minutes later
Remark: release the vacuum several times improves the degassing. For easier degassing only fill a recipient to 1/3 of its height.
3. Cross linking
The best curing conditions are at 23 °C and 50 % relative humidity. The use of products at higher temperatures and/or relative humidity levels will reduce the pot life and increase the setting rate. As opposed to this, lower temperatures and relative humidity levels will increase the pot life and decrease the setting time. It is recommended not to use the product at temperatures below 20 °C; under these conditions, the final product performance levels will be difficult to achieve.
At 23 °C and 50 % relative humidity, the membranes can be demolded after 16 to 24 hours. In order to achieve the best possible performance levels from the membranes, it is preferable to wait for 24 hours before using them. The definitive properties will be acquired after 3 days.
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