I’m mostly just monkeying around and doing what I see other people do when it comes to making these molds. I hope I understand the process right, but I guess we’ll find out!
We took one of my head mannequins and taped him up with masking tape to keep him safe, and then added a plasticine clay layer and stuck the mask down ontop.
I mixed up some Rebound 25 and brushed on what I felt was a reasonably thin detail layer. It is not as thin as I thought it would be based on the photos I have seen of people using it, but it took to the model pretty well.
More, thicker coats of Rebound 25 followed as I tried to eliminate or fill most of the undercuts on the head before building a master mold.
Crude registration keys and a thicker line down the middle was brushed on to give me a bit more material to work with.
The way I have seen this done is to grab a sharp knife and score a thin line straight down the middle of the seam through the thickened middle section, about 1/8 of an inch deep, and then stick a ton of index cards / playing cards / whatever into that seam so that I get a dividing wall. Then I’ll put sonite wax on the rubber, mold release the whole thing, and cover it in a layer of plasti-paste so I start making my mother mold.