One of my other hobbies is pottery, and I recently built a home made kiln. I just did the first bisque firing in it a week or so ago, and it worked perfectly. Here's a link to a video of the firing:Originally Posted by AquaTex
[youtube:1toubrvs]http://www.youtube.com/watch?v=nRC_wunARes[/youtube:1toubrvs]
Not to burst your balloon though, but by the time you add up the cost of the kiln and associated components, the multiple times you will have to fire it (and buy propane) to get a meaningful quantity of media, and the labor involved in making the little clay balls, I really think it would be cheaper and easier to just go buy the media. If you do decide to go ahead and make your own, you might want to try using paper clay rather than mixing goat turds in the clay. Paper clay is pre-mixed with macerated paper which burns out during the firing leaving an open and porus clay body.
Good luck whatever you decide to do!