iestyn gruffudd

http://www.backyardmetalcasting.com/refractories.htmlhttp://www.backyardmetalcasting.com/refractories.html

Many options seem to be available, could even just buy a bag of high temperature fire concrete.

Although there are advantages to these methods for construction of a furnace, there is something I find very appealing in techniques / methods that rely on burying holes and using the soil as insulation instead.