I spent a little while cleaning up the plaster before painting a few layers of latex into each half of the mold. I also had to remake the armature as I managed to break the one that was inside the original Plasticine hand.
After laying the armature inside the mold I poured latex into each half. I find the best thing to do is leave the latex to dry for a few minutes before putting each half together as it reduces the amount of latex that spills out.
In the place of clamps I had to improvise a way of keeping the two halves pressed firmly together. It's lucky that I have so many elastic bands. I left the latex to dry overnight.
This was the result. The latex was smooth and a uniform colour throughout. The last step was to cut away the flash(extra latex) around the edge of the arm and hand.