sorry for not being clear … it is definitely convection. the herb sits in a flat bottom vial, the vial is put into the oven tube. the herb does not touch the heater.
the ribbon is encapsulated … there is a stainless steel washer 1/8" below the top of the oven tube - not shown in the diagram - that seals the interior of the cube from the oven tube.
this shows the top of the cube and the gap around the top of the oven tube isolates the hot oven tube from the wood. the washer sits at the bottom of the gap - centers and steadies the oven tube at the top, keeps hot tube away from the wood to prevent checking (splitting), and keeps herb from falling into the inside of the cube.
the vial is sitting next to the cube. when the vial is inserted into the oven tube, and is flush with the top of the oven tube. the vial is 35mm long, 12mm diameter.
the ribbon is encapsulated … there is a stainless steel washer 1/8" below the top of the oven tube - not shown in the diagram - that seals the interior of the cube from the oven tube.
this shows the top of the cube and the gap around the top of the oven tube isolates the hot oven tube from the wood. the washer sits at the bottom of the gap - centers and steadies the oven tube at the top, keeps hot tube away from the wood to prevent checking (splitting), and keeps herb from falling into the inside of the cube.
the vial is sitting next to the cube. when the vial is inserted into the oven tube, and is flush with the top of the oven tube. the vial is 35mm long, 12mm diameter.