I'm trying not to waste propane, and while my first mods have helped, I'm thinking an insulated sleeve around the pot itself will help a lot more.
So far I have used wind breaks around the open base of the Bayou double jet burner rig I use, and a sheet metal cylindrical sleeve that fits loosely around the propane tank pot I got from D Crockett. During heating the lid of a Harbor freight 12" Dutch oven covers the pot with a near perfect fit. The top edge of the sleeve is bent in close to the sides of the pot, both to trap more heat and also to give a little clearance to the pot's edge allowing me to use vice grips to lift and pour out the remaining melt after ladling out ingots. This set up takes a third to a half of a full twenty pound tank to melt 200 pounds of alloy starting from cold scrap, on the lower side if I get impatient and blast the top of the uncovered scrap pile with a weed burner run off a second tank (and I don't know how much propane the weed burner is using).
I'm figuring to sandwich mineral wool or ceramic wool (the latter is more expensive but is rated to 2400 degrees) between the current sleeve and another smaller diameter sleeve inside it. I have near zero sheet metal working skills but can probably manage a few bends and crimps like I did for the first sleeve by way of holding things together. Cost will be forty or so bucks. I figure on melting/ingotting/alloying 3000 to 5000 pounds a year.
So, is this worth the dollars and the effort? Any recommendations on whether the fancy ceramic insulation is the better choice? Are there ways of reducing exposure to the airborne fibers from the material during sleeve construction and actual use in melting (all sorts of warnings posted in forums on use of this stuff, partly on consumption which is not an issue, and on inhalation, which is).
Thanks in advance.