I am building a new furnace out of a keg, essentially following Brian Oltrogge's FIRE-KEG build. Instead of making the walls out of castable refractory as he did, I plan to use 2" kaowool and coat it will about 1/2" high temp mortar to shield it (and prevent any nasty health effects from heating the kaowool). I plan on using just a simple furnace mortar, the type that you pick up at a big box store, but I'm unsure how well it will work being only 1/2" thick. Does anyone have any experience with that? I know that Satanite would be the best option, but I would prefer to avoid that if I can since