ANSWERS : Workshop

I've tried other diy methods such as silicone caulk and Plaster to make molds.  while the plaster was the closest to working it was very difficult to remove the resin from the mold. 

Comments

[rickharris]

MUST use a release agent - In a small mould a good oiling with veg oil may do the job otherwise get some PVA release agent.

your finished product is only as good as your mould.

[CrLz]

Did you try using a release agent? Vaseline / wax in a light layer on the plaster cast surface. This stops the resin from adhering to the cast.

[Dr. Pepper]

Clay?