For Gregor's puppet, I want a big blocky sculpt, but I don't want the mess and hassle of foam latex so I decided to build the puppet straight on the armature. I want ball-and-socket armatures for all of the puppets, but I don't have that kid of money so I decided to try out one of the armatures from. They came as a kit that took an hour or two to assemble and in the limited playing around i've done, it feels fairly smooth. I don't have much confidence in the armature's strength, so I was careful not to tension it too much. Just enough to stand on it's own. I got it from www.animationsupplies.net .
Gravity is the mighty enemy of stop-motion so it's important to make you puppet as light as possible. Chair foam is a great light spongy material. I traced a general outline into a block of foam and then cut it out. I then cut that shape in half, front to back and sandwiched the armature into the middle using some Barge. I carved the shape down with a razor blade until it was close to the right shape. The torso was so choppy that I laid some thin sheets of foam to make it a smooth surface. Now I had a naked foam Gregor.
There are different ways to costume a stop-mo puppet. My favorite look is having the cloths sculpted in foam or foam latex and then glueing the cloths to the surface. This is nice because it adds all of the texture and detail of real fabrics but maintains some sculptural quality that you'd lose if you made pants and put them on the puppet. What you glue with depends on the foam and the fabric. I have a stretchy material thats pretty thin for Gregor so I put pros-aid directly onto the foam and let it dry.
Then a cut a loose pattern for the parts of the suit and stretched them over the foam. I rub the fabric to get all of the air pockets out. Then I used some fabritac here and there to really secure the fabric.
Once the suit was basically done, I sew some seams and then glue strips of it to the puppet so the suit looks sewn and not glued together. Add a few buttons and cuffs and he's ready.