Hi Made from the bottom plate from the packing of a scotch delicacy. I used an original Petromax heatshield for spacing and size of holes to achieve proper airflow. Sizes Are 6mm, 20mm for preheater (I made a couple ) and 35mm for the vaporizer. The tag is there to lead flames up from the meth-cup.
@bjornego Thanks for sharing . That is such a easy design . I don't know why I hadn't thought of that myself ?