I'm often asked how I work and the difference in creating a statue verses an action figure. The process for an action figure/statue aren't very different. The scale and complexity of a statue is generally different from that of an action figure, but for the most part the process is nearly identical. I sculpt in a wax like material called castilene. I keep chunks of it under a heat lamp, which keeps it soft for me. Castilene is fairly hard at room temperature, and the heat lamp warms it to a consistency more like sculpey. Since castilene is pretty hard when cooled, I don't generally need any armature so I can just start blocking in a statue/figure right away. I will armature really small parts (Fingers/ hands and strands of hair). I Mostly use my fingers to do the early shape blocking and gradually refine the surface with various sculpting tools. When I've got my sculpture looking pretty much the way the final will look.. that is, where the pose and costume details are all represented roughly, I'll plan out where I need to cut the figure for either articulation, or for ease of molding in the case of a statue. Both a statue and an action figure needs to be cut into parts for easier molding for production and for articulation for an action figure. When I've got my sculpture in pieces, I use square rods to reassemble the statue. I make sure everything fits well and go on to finish the piece. For an action figure I add individually tooled joints where the figure has been cut into pieces. All the hinge joints like the elbows and knees and t-crotch will work on the original wax sculpture just like they will in the production piece. For the ball joints, I'll use a sphere of plastic or a marble or something to hold the place of a ball joint. Final engineering for those are done in the factory. When I've got the joints in and working, I'll finish the sculpture. The finishing is the most tedious and time consuming part of the process. I generally use my tools and sand paper to do all my finishing work.
For more information on my process and other toy sculptures, check out Pop Sculpture: How to Create Action Figures and Collectible Statues by Tim Bruckner, Ruben Procopio and Zach Oat.