When you find a product that sells well it is important to ensure a good supply of the item. In my shop www.oscarcrow.etsy.com I specialize in both metal jewelry and ceramics. Both old vintage doll parts and newly created copies of my favorite pieces. Since many of these are one of a kind I feel like keeping them forever...that makes me a collector ? Or just a hoarder? But I like to share with everyone so I make copies. This technique will work equally well for those of you who work in Ice Resin or polymer clay. A great book for using Ice Resin is http://www.bsueboutiques.com/item/Explore-Create-Resinate-by-Jen-Cushman-7614
To make a mold I use oil clay that never gets hard for a base and embed the heads in it half way then spray Pam cooking spray over the surface lightly and pour plaster over the faces. The sides of my mold are wood held together with wood screws.
The result is shown here a negative impression with the details fully realised. I am using US Gypsum No. 1 pottery plaster. It is a very hard and durable material. If you work with Ice Resin you would want to treat the fully dried mold(at least 3 days) with a suitable mold release. Cushman's book and Kazmers' website will have details on the best to use. If you are working with polymer clay I would suggest http://www.bsueboutiques.com/item/Original-Sculpey-8464 and condition the clay very well then push it into the mold firmly and it should release and result in a very workable product.
I work with liquid clay called raku slip. I pour it into the molds with a turkey baster and let it set up. Capillary action in the dry plaster pulls the water from the clay and when the clay has shrunk away from the sides it is ready to remove from the molds. I make holes for stringing at this point by piercing the clay with a square brass tube that I rotate leaving a smooth hole. Then the pieces are off to the dehydrator for drying. When they have become dry I fine tune the parts and sand or trim as needed . Next they go into a kiln for a 4.5 hour bake at 1856 degrees cone 6 . Then the pieces are ready for glazing and another soak in the kiln and then reduction if raku is the final state. If I use regular glaze I let the kiln come down in temp overnight and remove the pieces then.
This is last nights firing. From the top is a doll,two angels that I created from separate parts. Notice the different colors in the clay...the wings are one clay body and slightly pink while the bodies are white. Second row are two pawns from a chess set I am creating...boys heads on one side for pawns and girls on the other . Next is a skull doll and a bust. Then a doll and a head bead a face cab and a round bead. And the final row has another doll body and three frozen charlottes that are only 1 inch tall. I now know why there are so many little charlottes broken..from a perfect mold I have pulled 1 without feet and a broken arm,and two with out heads...very frustrating learning when to unmold the tiny doll. Last is a face cabochon. Something I have learned with this is that items made in this way shrink from the original size about 10%. This is how we can make smaller and smaller copies by making a mold of a copy.