They claymation I have done was just with cheap modeling clay; I'm not sure if that is what you are using, but I have never had good results from running wire through them. I've tried different gauges without success, and I've tried pipe cleaner as well, which also doesn't work. As I'm typing I'm thinking that maybe solder would work, 'cause the main problem I've had with wire is that is cuts through the clay when you move it. Lead solder might be thick enough and still soft enough to work, depending on the size of your characters. What we have always done is just used straight clay, with no wire or anything in it. Problem there is that the lights make the clay soft real quick, so keep a refrigerator handy.
One other tip that might be useful is to create multiple feet or hands for different applications. I know that Aardman (the Wallace and Gromit and chicken Run guys) Studios uses this technique for their faces-- they have a whole tray of heads, with different mouth shapes, for different expressions and vowel sounds, and they just switch heads, so that there is very little changing of the shape of each piece. This helps the head to last much longer than it you were re-shaping the same head each frame. It seems that the same technique would work for other body parts.
Hope this helps, keep us posted on how its going, and if you have any other questions that maybe we can help you with.
Last edited Tue, 1st Jul 2003, 5:55pm; edited 1 times in total.