BRONZE CASTING PROCESS: POST 3
KEEPING IT TOGETHER
Many forms one might wish to create need some sort of skeleton upon which to build. In sculpting, this is called the armature. The larger the piece, the more armature becomes important, but even very small pieces often need a good armature in order to keep the form together, and resist deformation.
I make armatures in several ways. Usually copper tubing or thick aluminum wire is enough. Sometimes wood is also involved. The armature of any figure should have the basic components of an actual skeleton. If you are sculpting a human figure the skeleton will look about like the one in your closet, but without the top-hat. It is a good idea to make the joints somewhat malleable so that you can adjust the posture as you go. Copper tubing is friendly in this regard, as it is easily bent. For very large sculptures, the armature is scaled up accordingly.
Once you are satisfied with the figure that is described by the armature, bulking up the form becomes the main focus. Many artists do this with clay. I don’t. I prefer to feed the skeleton a protein rich diet, with plenty of carbohydrates and let it bulk up naturally. When this doesn’t work, I use polystyrene packing foam, and less often, expanding spray foam. Both are stiff, light weight, closed cell, and carve very easily with a knife or saw. The foam can be added to the armature, much as a group of med-school students might put a cadaver back together. With a little heat, (yes, fire!) the polystyrene foam will melt and glue itself to the armature. I put too much foam on and then carve it back to where I really want it. Of course different sculptors would approach this in different ways, some preferring to work reductively, and some additively. In practice, almost any sculptor who approaches their subject as anything but strict anatomy will work in both ways, adding and removing bulk. I have studied and continue to study anatomy (not the kind for med students, but for artists), but reproducing a life-like form does not, in itself, interest me. I always work toward making something I have never seen, as opposed to trying to reproduce something from the natural world. I love nature, but I also believe that nature does nature best.
Armatures almost always come back to bite me. I want one thing, and then I decide that I want a very deep cavity right where a part of the armature is near the surface. Often the armature is compromised by cutting into it, and other means of keeping things cobbled together come into play. But one way or another the form only has to last long enough to photograph it and hold its shape while making a mold.
After I have carved the piece to the shape I want, I sweep my torch across the foam to create a skin on the surface. This skin helps stiffen the figure, and keeps bits of foam from coming loose. Ideally a thin layer of wax will be enough to get to the final form.
ADDING WAX
Most sculptors don’t sculpt in wax, but those of us that do, probably do it for the reasons I do. I use wax because it is hard and very tough when cool, and soft when heated. As my mother once pleadingly pointed out, in a moment of exhausted frustration, I wreck things! I ruin things! I be breaking things down! (Of course, as you can imagine, us kids absconded with this little ditty, born of despair, and for several years thereafter, well, fifty-five and counting, we sing it back to her at family get-togethers, complete with four part harmony and whatever instruments of percussion might be at hand. “Youooooo are wrecking things, you’re ruining things, you’re B-B-B-Breaking things down!!!” So, you get the point. We are just a very musical family.)
I’m no longer careening around the house, bashing into things on my little brother’s tricycle, but I am too “animated” to work in a soft medium. A clay figure can be easily damaged or destroyed when it is run over by the lawn mower, or even just dumped off into my lap. But if my plan was to make a large messy mud-ball, I would definitely work in clay. Or mud.
Beyond being tough, wax is far more friendly to textural complexity, and I am a texture artist, if that is a thing. I love textures as much as form. Wax can be melted and poured over the figure, or it can be applied with a spatula or paint brush at warm temperatures. It can be applied by hand in bits and pieces, and it can be carved like wood. It can be further shaped with hot tools, and of course, FIRE! It can be frozen and broken into nice textures, or laid out in sheets and draped over a form. Wax is my friend.
Once I have the figure exactly as I like, it is time to dissect the piece into parts that can be molded.