I know Darren and Katie. Nice folks and a very good array of products. I just bought 60 lbs.of heat treating salts from them at the BBS. My email lost the second S. as in Stainless steel. The heat oxidation from hot spots is very easily visible. 3" of kao wool is overkill. I only use I" of Inswool HTZ 8 lb 2700F. Chuck