Furnace for what?
I am assuming you plan to melt metal, no? If so then get over to
http://groups.yahoo.com/group/castinghobby
and join up before you make a big and costly mistake.
Here is a link to my foundry pages:
http://www.foundry.ray-vin.com/
where you can see the construction of my furnace and other casting items.
If you aren't planning on casting metals then please accept my apologies.
Regards, Ray in FLA
"There is no such thing as a gun free zone."
Ray Brandes, Ray-Vin.Com, PCB, FL 32408 USA