I have always had trouble with melting and pouring iron, and some of that is due to the fact that iron is very particular about how it is melted, and part of it is due to what I think is too much mass in a furnace. Others have used high-mass furnaces successfully for many iron melts, and so I can't totally blame my iron problems on the fact that it takes 30 minutes to warm up, but I have also seen others use low-mass furnaces with great success in melting iron, so I know it would certainly help things along if the melt went faster. So with the intent of speeding up the melting process and expediting my iron-melting experiments, I have decided to make a new iron melting furnace, centered around a beer keg (edit: As it turns out, it ends up being the diameter of a 55 gallon drum, and requiring four beer kegs). I tried to keep the dimensions inside a standard beer keg, but could not do that and also make the furnace large enough to contain a range of crucibles, such as a #10, 16 and 20. So I chopped up the beer keg to make it larger. For the hot face, I am using 1" thick Mizzou, and so the trick has become how to ram a hot face that is only one inch thick, but quite tall. My solution is to make stacking shell sections so that I can ram one section at a time. Hopefully I can keep it all straight as I go up; I think I can with 1" wood spacers. Edit: The stacked shells are not necessary, just use a single shell and ram about 1" of refractory at a time, packing it well with a 1/2" wood dowel rod. Everything is waterproofed with heavy duty foil tape. I have tried a dual burner arrangement in the past, and did not really find an advantage to doing that. The dual-burner arrangements that are seen in commercial units sometimes occur when the crucible and furnace are relatively tall, and so the burners are stacked one on top the other, but some commercial furnaces do have dual burners at 180 degrees at the same level (at the bottom of the crucible). I have accumulated a lot of clean iron (about 1,000 lbs +) which consists of motor end bells. I do model engine work, and it is very advantageous to have an engine cast in iron for the machinability and wear characteristics of gray iron. I have spent a serious amount of time studying and reading about the iron success stories, and so hopefully I can pull it all together and get somewhat consistent iron melts/pours, or at least as consistent as what some others have achieved. My original design had 1" of Mizzou, and 1" of ceramic blanket, but I decided to err on the side of caution and use two layers of 1" ceramic blanket on the outside of the Mizou shell. For the lid, I first considered using the metal beer keg top, but I may cast a dome in Mizzou, and then lay a layer or two of ceramic blanket over that, and rigidize the ceramic blanket with ITC-200 mixed with water and sprayed on in a couple of coats, thus avoiding using the metal lid, and avoiding the metal lid from becoming a big heat sink. Below is a section of the furnace, and the cuts on the shell. The shell will have to be pieced back together, but that is not really a problem. I will be using stainless crimped 1" refractory needles to prevent cracking. Others have used them and reported no cracking with extensive iron melts, so I felt it worth a try, especially since my last furnace has cracked badly with no needles, and I noticed photos of other people's refractory also cracking without needles. Edit: I modified the design a bit from this original sketch, and the modified design is posted later in this thread.