Here I have finished the beak casting by removing the extra resin, and I've returned the plasticine I cut off earlier to the end of the beak.
Since the resin beak will sit atop the leather I need to extend the clay underneath it, but reduced in size to fit within the beak. I've marked in red where the leather trim will go.
Tape won't stick to plasticine, so I have covered the clay in a brushed on coating of urethane resin.
Once the resin has cured I remark my seam lines with a black Sharpie™, and then I've started covering one half of the face in blue masking tape. Since the mask is symmetrical I only need a pattern for half of it.