From the Email Bag:

This question is stop motion related and not of interest to all but as Yogi said, bear with me. (reprint from my ASIFA Blog)

Hello,

I read your blog at ASIFA, and I was wondering about your preference for 10 gauge copper wire with insulation over 1/16 aluminum wire. Does it bend easily? What scale is good for that gauge of wire? Does it break as often as lead or tin? (I use solder with a replaceable parts armature design)

Thanks,

Don Carlson
stopmotion animator
Pram Maven Films

Wire armatures, used primarily for clay animation, are short lived by nature. Because the are cheap and quick they have a real appeal. The trick is to build them to last long enough for the duration of the shoot. The weak points of any armature are upper arm and elbow. Which is why I often build wire armatures with replaceable arms and some times with replaceable hands so that only the arm is replaced.

Aluminum is stronger than cooper, no question about that. But strength in not the answer, durability is. Aluminum is strange stuff. When you drill it aluminum comes out of the drill hole in long raiser ribbons. When you bend it repeatedly it gives in one area and develops a memory and then continues to bend in that area alone until is cracks across the bend. It short, it is brittle.

Cooper is a softer material but it has real durability. It tends to bend over a wider area spreading the stress. By leaving the insulation on the wire you increase this trend. And if worse comes to worse and the wire parts the insulation will hold the limb to the body even if it will no longer hold the pose. You can even open up the arm and push a couple of straight pins long way through the insulation to build a kind of internal splint. (The trick is to bend the head of the pin at a 90 degree angle and then use a pare of needle nose pliers holding the head of the pins to insert the pins through the insulation)

As for size, 9 inches is the best height. Larger than that and you start running into the inverse square law. (things that double in size are squared in mass) Smaller than that and the wire skeleton is too heavy for the body. Here are a few images from my ebook, Animation on a ShoeString (tm) to give you an idea of what I am talking about.