Making a Metal Melting Furnace (Simple, Effective, Propane)

At the new place I can't just light a stinking coal fire in the backyard like I used to, so I had to find a cleaner and more controlled way of melting aluminium. I thought about building an electric furnace, but that seemed to be too much work and too prone to failure because of breking coils and comes with a number of other problems. So I decided to make a propane furnace and keep it as simple as possible. As an outer shell I used a steel barrel. As a mold for the inner chamber I used the container of an old herbicide sprayer, because I couldn't find a bucket of the right size and didn't want to buy one. The substance of the furnace was made from a mixture of fire cement and perlite dry fill insulation. The perlite will insulate the furnace, hence making it more efficient, and the fire cement will glue the perlite particles together to form a solid mass. This also makes this furnace remarkably lightweight.