st for that diorama, the first being some glass apparatus for an electrical device (don't know the name of the thing, even in French), the second one is some glass brick for some factory wall.
To do the electrical thing I used some bottle from an old Verlinden (?) resin sprue as a base ...

while I used some old PE grid to make the pattern on the glass brick.

I then worked a plastic form around it and put some silicon over it.

Hey but how do you prevent *bubbles* in the form??

The solution was provided in the excellent "STATIC MODEL MANUAL Building - One hundred and one tips". Well, at the last pages of the fine book, there are quite a few pictures and explanations about the device you have to build to make a sort of pump that will suck out the air in the form. So, being mostly unable at 1/1 work, I went to my stepbrother who despite having a zero tolerance / interest for my little things accepted basically built the machine for me :)

In 30 seconds I had some wonderful bubble free silicon forms :) (to be continued...