Mini Charcoal Furnace

Step 2 Furnace core

To shape the furnace core I used an empty plastic can of paint. Cut it to the desired diamater leaving space for the charcoal / crucible and at least 2" to fill the refractory for furnace walls. Using masking tape to hold the can diamater shape makes it quick and easy  to remove after your refractory is dry. Make a hole for the cardboard pipe or just tape the pipe to the can to prevent blockage of the opening.