A simple model of a flame in a brazier that I made. I suggest printing it with a brim (I had two prints detach from the heated bed on my Prusa i3 MK2 before using a brim). Both models can be printed small (3-5 cm) but there shouldn't be a problem scaling them up (I'd love to see a bigger print!).
Ps. The metal flames were made by casting tin into a silicone mold made from the red PLA print. Ds.
Use a brim/skirt for bigger surface area against print bed.