Hi everyone...I'm pretty new here. Been reading a lot and have a question. I'm researching building my own forge and would like to know how hot will the outside of a properly insulated forge get?I'm thinking of building one from an old 5.16 gallon beer keg. It's about 9 1/2 inches in diameter and 19 1/2 inches long but not made from stainless steel. I don't plan on keeping the length that size and would like to use one Frosty burner. Any thoughts on this idea? Thanks.