This is my first furnace. I have based the furnace design on the classic “Flowerpot” method described by Lionel Oliver on his excellent site (
http://www.backyardmetalcasting.com/).
Basically, the furnace is a large terracotta pot that has been lined with a refractory. I searched online for a suitable mix and came up with 3 parts fire clay; 3 parts Portland cement; 1 part perlite. In retrospect, sand; Portland cement; fire clay and perlite would have been better … but … whatever.
I used a plastic flower pot to make the void in the middle where I will burn my fuel and a steel tube for the air intake.
I let the refractory cure for a week and then gave the furnace a test firing.
I dodgeyed up a connector for an old cheap vacuum cleaner for the fan and connected it to the furnace. The burn was pretty good. Initially, my crucible was a stainless steel pot that I bought from the tip shop. This gave me about half a kilo of aluminium, but the pot was a little thin, so it died after a few firings.
There are loads of resources out on the web for finding good recipes for refractory and cheap home-made furnaces. I suggest that you look far and wide and read as much as possible. Start small and have fun.
