Hi! Does anyone know what 'Wacker Cenusil 830' is and what it is for?
It looks like it is a RTV silicone rubber used for mold making.
It appears to be a 2 part addition cure (platinum) silicone primarily used for mold making. Shore A hardness rating of 26 indicates it is quite "squidgy".
So it would typically be used to make a mold of a sculpt or other object, reinforced with a rigid outer shell (or "jacket")
This table shows that it's somewhere between the hardness of a rubber band and a pencil eraser (middle row)
Here's some data on it
Mix ratio of the two parts is 1:1
A similar tin-cure alternative would be MoldMax 25 or MoldMax 30 from SmoothOn: