DIY Propane Kiln Cone 6 (cost $200!)

I have tested this kiln to get to 1200C in under 8 hours and using less than 20 pounds of propane! That seems to be about the limit, but I am still experimenting with firewalls and ramming air to get some hot spots. I made a simple ash glaze that has fired well at cone 5 in this kiln.
The most important factor I have found is that the inlet and outlet of the kiln must be large enough to allow for efficient combustion. I am using a Lincoln Inferno weed torch ($60 at Home Depot) and the inlet to the kiln must be at least as large as the torch head.
Then it's just a matter of blasting in enough air at the end of the firing to get to the desired temperature. The red tube around the torch is a clay flue that I found (a piece of metal duct would work) with a fan blowing in to ram air into the torch head and kiln chamber. By adjusting the gas and by moving the torch and the duct closer or further from the opening, you can acheive optimal burning. I found that if the kiln is smoking or if a flame is shooting out the chimney that you don't have sufficient oxygen to acheive complete combustion and optimal heat. One other suggestion is to use 2 propane tanks: one that is about 1/4 full to start slow, then switch to a full tank at about 700-800C to get to the finish line! Good luck!