The above diagram that I made in Inkscape will help illustrate what I am planning to do.
1. The beige color is for the non-sulfur clay buildup. I plan to give my bjd's head a removable faceplate so that means her neck joint must be joined with the back of her head. If I made a removable head plate, her neck joint would be joined with the front of the head. At this point I would pour the silicone rubber for the first part of her head mold. What you can't see in the diagram is the need for mold keys in the clay buildup.
2. With the clay buildup removed her head is now ready for the second pouring of silicone rubber. If you haven't noticed yet, there are no pour holes in either of these parts. The pour hole was not accidentally forgotten but is part of the plan. After pouring the second silicone mold for the head, it is time to make the head hollow.
3. & 4. This next part will be the third pouring of the silicone mold and requires a lot of care. A clay buildup is made inside the head and face molds at the same thickness as I want the resin copy to be. I would also be adding the pour hole and air vents. The air vents will help bubbles from getting trapped by creating areas where they can escape. My diagram does not indicate where I plan to add the vents, but if you look at the gallery I posted at the beginning you can see how it can be done.
A. This is where the neck joint is. I did not include a diagram of how I plan to make this slot yet, but be aware that some clay sculpting is needed in this area to ensure a proper neck joint socket is made.
B. Her head will have magnets to help make it easier to remove her faceplate and to hold it in place. I will have to make a buildup in clay for this. Additional means to help keep her head aligned will be needed as well. The hard part is to have both halves of the head match up.
C. If I were to put clay over her eyes, I would have to cut them out after every casting to make the eye hole. Instead of adding extra work, her eyes will be devoid of clay so that the silicone will pour into it leaving an empty spot when the resin is cast. Extra care is needed to ensure the clay buildup around the eye is not too thin and has clean lines.
Her head has a total of 4 parts to make the head and face plates separately.
Part 1 & 2 REDO
Part 3 & 4