Some key details about using silicone gel materials for plastic vacuum casting:

Silicone Gel Materials for Vacuum Casting:

Silicone gel materials, such as room temperature vulcanizing (RTV) silicones, are commonly used for vacuum casting applications.
Silicone gels offer good flexibility, elongation, and tear resistance compared to rigid plastics.
They can capture fine details well and produce parts with a soft, tacky surface texture.

Hardness of Silicone Gel Vacuum Cast Parts:

The hardness of silicone gel vacuum cast parts can vary depending on the specific silicone formulation used.
Typical shore hardness values for silicone gel vacuum cast parts range from shore 00-10 to shore A 20-50.
Softer silicone gels in the shore 00 range (0-10) will produce very flexible, rubber-like parts.
Harder silicone gels in the shore A 20-50 range will have more structure and rigidity, but still maintain good flexibility.
The hardness can be adjusted by selecting a silicone gel with the desired Shore A or Shore OO durometer rating.

Advantages of Silicone Gel Vacuum Casting:

Excellent replication of mold detail and surface finish
Ability to create soft, flexible parts
Good tear resistance and impact absorption
Versatility in hardness range from very soft to semi-rigid

Overall, silicone gel materials are well-suited for vacuum casting applications where flexible, soft-touch parts are desired. The specific hardness can be tailored to the application requirements.