In this video, Smooth-On fan Jara shows how to make fake potion bottles using Encapso-K silicone rubber.
Encapso® K is a water clear encapsulation rubber that looks just like water and is ideal for a variety of encapsulation and display applications. Two clear liquids (Part A and Part B) are mixed together in equal amounts. The mixture is then poured around artificial flower stems or over an object.
The mixture turns from a liquid to a solid, soft rubber overnight. When cured, Encapso® K looks just like water and will last a very long time.