Thanks for all the input, it has been really helpful. However, since I don't have a forge or space for one, casting is out of the question. Also, for those of you who are wondering, the curved sides are very important to ensure the correct air flow and to help with the pitch. They can vary according to a players mouthpiece preferences. With this project however, I don't intend to make anything too custom, I just want something playable (as sort of a trial project). I actually chose the french horn mouthpiece despite the fact that I play trombone because I don't have to worry about too much material being wasted if/when I mess up. Thanks again for the help and I hope I added some clarity.