I have melted small crucibles of bronze in a ceramic kiln. I plugged both holes in the kiln door with refractory. Ceramic kilns take hours to come up to temperature. Electricity is expensive. Melting metal in the basement also entailed certain problems. A friend bought cast-able refractory. It looks like concrete, but dries without water of hydration and will withstand high temperatures. He made a removable core and placed it inside an old steel beer keg. He then poured the cast-able refractory around it, let it dry, and removed the core. That gave him a furnace. He cast a lid from the extra cast-able refractory. Using a masonry bit he drilled the inlet hole at the bottom entering at an angle. He took a squirrel cage blower and attached it to a length of conduit which went into the inlet hole. In the side of the conduit he attached a nipple for propane. To run the thing you turn on the fan and propane (on low!) and drop a burning piece of paper into the chamber. The propane requires a low pressure valve of the sort used with stoves. The fan needs to be small.