I'm actually quite good at bongsmithing, thank you. I've had great airtight pieces with minimally toxic materials...and what's with the plastic fumes? Unless your bowl/screen are made out of plastic, you have no worries. Mere heat conduction through metal isn't enough to evaporate plastic. Maybe melt a LITTLE, but not evaporate. I doubt it'd melt unless you're a dumbass who doesn't know how to cherry a bowl.