What mod were you using? I find it odd that a regulated mod would not detect a short that would melt your delrin like that. Also, what build were you running? I find that these Kayfun type tanks tend to perform best at around 1.1-1.3 ohms at 15 watts on regulated mods, and around .7 on a mech. That's just my opinion, of course, but I get plenty of flavor and vapor running in that range.
Edit: fixed my thought....
