Harold,
You can make just about any horn with just a hacksaw, files, a blue magic marker, a scribe, a ruler, a small square, 1/16" tool steel for single blade horns or 1/32" for double blade horns, and a drill. You would be pleasantly surprised at the level of quality that simple hand work can achieve. Total time to make an elevator horn would be less than three hours even with limited experience. The upside is that you can now make EXACTLY what you want.
Kim.
What Kim said, except that he left out the need for a good hefty soldering iron or a torch.
I make my horns more or less the way that Kim does, except that I braze them on with an oxy-acetylene torch, and because brazing is almost as strong as a weld, I don't need to use the little reinforcing rod that he does.
Like these. Pic. taken in 2012, and the plane has well over 500 flights on it with no control system trouble:
Well, except for these, which are silver-soldered and reinforced. The reinforcement isn't like Kim's but it's done for the same reason: