Here is the first video of his Mordor project, he doesn't have any of the others up unfortunately. You can see that he has been classically trained as a sculptor and uses materials I haven't seen used since I worked in movies a long time ago. Please note that fiberglass is very dangerous to one's health so don't muck about with it unless you know what you're doing. I'm not please with the "little Major" character but I'm happy to say he abandons him in later videos.
Sorry trying to post too quickly. This video illustrates brushing on the first layer of silicone to make sure you get the details and reduce air bubbles. The blue stuff is silicone. Next he layers plaster on top of the dried silicone mold to form a base for it to rest on when he pours the resin in. Notice he also brushes on the first resin layer.