If you have an armature inside of a polymer clay sculpture, will the clay crack if you bake it?

I know it will if you do it in other clays, so is it safe to do?


No,

As polymer clay is a plastic and the armature is a wire one there is no moisture to expand or contract causing cracking.
Polymer clay is a clay by name only,
your biggest problem will be distortion as it will get softer before it gets harder.
you get away from that issue by getting it up to its curing temperature as fast as possible and not bake it for more than five minutes followed by actually letting it cool without fiddling with it unless you have to.
as long as you build in layers from the first muscling you'll be fine.
(the big issue is that it will be hard for the core of the material to cure if theres too much mass around it causing distortion or even shapeloss.
the shorter baking time is to compensate for rebakes later as you don't
need more to make it survivable as long as it reaches bake temperature in the core. be carefull when your doing the first layer and make sure you use a metal with a high enough melting point thats properly fastened to itself rather than the polymer as this is the point when most of the distortion will probably take place. the rest will be a breeze as long as you prep and soften the material properly while working on it and have a good rest for the sculpt so the unbaked goods wont have to touch the hot areas or lean against stuff during baking, kinda standard procedure I guess but it might be good to mention it in any case.
(i.e. keep a few unproccessed areas to use as points of contacts and do the layers in two bakes rather than one if you dont have an armature stand thats oven resistant)
Thats all I got for now.
It can, but it won't always do it. You have your best chance to avoid the problem if you bake it low and slow. Set the oven at a temperature 100 degrees Fahrenheit lower than the package recommends and bake it 1 1/2 times longer. No guarantees, but this does improve your odds. What clay are you using? Sculpy seems to work the best for this. You could also try using a plastic or wooden armature rather than wire. They tend to cause less trouble as well.
It would probably be Super Sculpey, and thank you. It would def, be a wire armature though.
You should be ok. Make some smaller test models first, just to see how the materials behave together, and whether or not the clay will cure at a lower temp. Best of luck!