I just tried something new a while back. Tools I used were a butane torch, copper sheets, a bowl of water and a pair of old tongs. Not your normal raw materials when you think of painting. But, Yes, these are what I used to paint with fire.
Apply heat to copper and you can get a whole range of colors from a subdued ombre to bright yellows, blue, red and gold. The way you apply the flame to the sheet and pull the flame across the blank copper canvas (sheet) will make the beautiful colors jump at you.
This is definitely not for the faint of heart. These pieces are bold.