carts melt from pushing a metaltube enclosed atomizer too hard, heating up the tube itself. Entirely operator error, usually from chainvaping (abuse) or using atomizer/cart combinations on highervoltage
mods then they are designed for (abuse). Not all ecigs have carts that insert into a metal tube. Not all manufacturers want to accept liability for use of higher-voltage mods, so they don't design their atomizers/carts to accommodate higher voltage or chain-vape conditions. For instance, VG can morph into some pretty nasty stuff at higher, extended temperatures whereas it's pretty inert at short-burst, normal tempertures.
Considering the number of chemicals used in
eliquid, most of which we don't know since we usually purchase relabeled product that lacks ingredient lists, it's probably safer healthwise to stay within the lower voltages manufacturers recommend and build their equipment for, and leave the high-voltage mods for the Darwin Award volunteers.
I've heard the 'pot' described as both ceramic and porcelain
TTRP