How hard are you sucking? I think this is the issue here. I just got the herc/perseii and tried loading up some reclaimed vapor oil, which was way too thin, and just leaked all over. One thing I noticed, was if you sucked hard enough/fast enough, you can hear the oil tank sliding up and hitting the mouthpiece. So it sounds like the oil tank gets preheated, then when you suck (too) hard you pull the hot oil container off the heater, and up against the metal mouthpiece screen. Its pretty thin, so the heat transfers directly to the delrin mouthpiece quickly melting it while you are sucking.