Step 8: Headpiece: Horns
1) Making the base: The base for the horns is made with aluminum sculpture wire, which is quite strong while being lightweight and easy to form. They were fleshed out with finer aluminum wire and some light-gauge hardware wire I had around.
2) Papier mache: To give a base for the papier mache, I wrapped the wireform base with masking tape. (Ghetto, but it works.) The papier mache is basically the same method you learned in grade school; I used tissue paper, ripped into pieces about 2"x2". I use wallpaper adhesive, which comes cheap in a nice big resealable bucket. Instead of dipping the bits into the adhesive, I prefer to brush some adhesive on my surface, then lay the piece down and brush it down with more adhesive. The blesbok (long) horns had an additional step to make the ridges, for which I used some nylon roping I happened to have.
3) Magic Smooth: Papier mache is great, and for some projects you could stop after the mache stage, but I wanted a hard, relatively smooth, horn-like surface. It was also critical that I didn't increase the weight very much. After a lot of research I chose to use a product called Magic Smooth. It's a two-part epoxy, but it's very thin, with a consistency rather like caramel (on an apple, not the hard candies). When dry, it's very hard and machinable. The very tips of the horns were done with another product called Magic Sculpt, an epoxy clay.
I mixed the Magic Smooth in disposable plastic cups; the only material it really won't stick to is silicone, so you will likely want all your tools to be disposable. I used plastic spoons to get a rough measurement to keep the 1:1 ratio, and also used them to stir it. I applied the coating with wooden popsicle sticks. Unlike a lot of similar products, Magic Smooth can be smoothed with water, and the best way to get it level is with a damp finger (wear gloves, it's highly sticky).
4) Sanding and painting: I did a light coat of sandable primer on my pieces before I began sanding them, because the Magic Smooth is translucent and otherwise it was too difficult to tell which areas needed work. I sanded the pieces with a sanding attachment on a rotary tool, and also by hand. I didn't try to get them "perfect" because animal horns certainly aren't.
After sanding the pieces were painted matte black, oversprayed gold, and then highlighted by hand with more gold and some red, then sealed.