I'm interested in building a conduction style vaporizer for purified crystal extracts. I'm not so sure about the material to be used, (or sure what the rules here permit me to discuss regarding specifics). Ideally, a pure crystal extract could be dissolved in ethanol, or a suitable non-polar solvent, and dropped onto a high surface area heating pad. Increased surface area would be accomplished by etching or machining. A finely etched surface would let the solvent distribute evenly across the surface by capillary action, and disrupt any large crystal formation. Heating could then evenly vaporize the material without unwanted pyrolysis. Metal is ideal because of its low heat capacity and machinability - but potential reactivity is worrisome. It's not so worrisome because temperatures can be kept low (<150C), but I'm having a difficult time determining if any toxic chemical compounds will arise from common metals. I am considering copper, gilded copper, silver, silver plated copper etc. Bare copper would be ideal because it can be etched chemically, and I can do so without any complex machinery. I am wary of the dangers of copper oxides, but unsure if they are a factor at low vaping temperatures. Applying a silver or gold coating to etched copper might overwet some of the fine detail and drastically reduce the surface area. I actually was considering just fine copper trace as the heat source on a commercially produced FR4 pcb since they can get tolerances so good, but the operating temperature is too close to the limit for the board substrate for comfort. Anyhow I've read some good stuff on this forum so I figured maybe someone here might have some useful technical advice beyond "dont do conduction vaping"