I do not know if I understand word "kiln". For casting you need mold and resin. You sculpt the object. Then you need create a mold (from plaster, but best material is silicon). Two or more parts of a mold, depends on the object. When is a mold put together, you can pour resin, or when is a mold only one half, you can use laminating technique (gelcoat, resin and glass fabric). You can do this in home, without special equipment, but you need use resins like epoxid, polyurethan... Polyester is cheap and easy, but this resin is toxic for styren monomer and odors.