Will I have problems with wire baked in oven baked clay? I am planning an armature for use in stop motion.  I will use 3 steel wires twisted together using a drill.  I am planning to have oven-bake polymer clay (such as Sculpey of Fimo) on the wires.  It would be wrapped around tightly to give some bulk to the upper arms, thighs, chest, head, etc.  

The clay bakes at 250º Fahrenheit (121º C).  At that temperature, will the strength of the steel wire be compromised if I bake it in the clay?  It is important that the wire is stiff, and is able to bend without breaking.  Will the clay break when fired around the wire?
Polymer clay doesn't shrink like real clay, so you don't have to worry about cracks/breaking of the clay while being heated.
Most types of metal melt at temperatures way higher than polymer baking temperature, so you don't have to worry about that either. I've made Fimo things with a core of aluminium foil, and no problems at all.