Mine is 6"x 6"x 36" of 1/8" aluminum sheet. Handles welded on each end. I heat it on an old aquarium stand with a homemade single 3/4" pipe burner(propane) under it. Cover it with a piece of aluminum flashing when heating and have flashing wind skirts on the sides. It comes up to a boil quickly and takes very little gas to maintain.

OB