Oh yeah , it's flammable . Even their Fire Block product is combustible over 240deg.I made one to go camping with the kids. We didnt insulate it at all. The outside gets hot but it cooks fine.
I thought about using great stuff foam. I dont think its flammable after it sets. I'm gunna have to try to find out.
check out a "penny stove" or "alcohol stove" i made mine it cost pretty much nothing but 10 minutes of your day and maybe 4 bucks for the fuel. i can boil water in two minutes and cook pretty much anything on it. it weighs a few ounces. love mine. i keep the fuel in a small squirt bottle and a few extra pennies taped to the bottom of the stove. well worth a look and whatever you do DONT buy one online they sell for 19 bucks and more but will cost you next to nothing to make. i used two pedia-sure cans to make mine.