>>2943922
cont'd
Here are some multi-part molds I made for more complex parts. I used metal rods, silicone tubing, backing plates, and master parts to pour the mold.

The metal rods would get lightly oiled, rubber tubing slid over them, then put into the molds. After the resin cures, you can pull the metal rods out of the silicone tubing, then the silicone tubing can be stretched until it releases from and escapes the inside of the cast part. This provided pilot holes (or even finished hole sizes) in the cast parts.