You could line the kiln with a ceramic fiber blanket. the ones on ebay are
rated to 2300 degrees and are about 1 inch thick
i recently checked and they were under $20 dollars a roll. you will need to
make some ceramic buttons and buy some high temp wire to secure it to the
sides but if your lucky find some old electric kiln elements and cut the
wire to the length you need.
j


"Bryn Salter" wrote in message
...
I want to build a Pottery Kiln out of a 45 gallon oil drum. What can I use
as cheap thermal insulation?