Originally Posted by Kalkail
In my amateur opinion heating/cooling cycles will probably weaken the stem although I am uncertain about the vase. I think if the concern is the desire for a cooler smoke, why not just alter the contents of the vase to something other than water? Or a sturdier cold resistant vase alternative? Of course this is discussed on another thread so I best just refer to that rather than dragging it out here.
it wont weaken it at all. your not heating or cooling to any extremes. in fact after steel is heated and quenched for high strength items many times it is put into basically liquid nitrogen for a while which strengthens it due to the extra carbides leaving (iirc, i just woke up but i think that was right). metal will not weaken from cycles of 25*f-75*f, heck you dont have to worry about metal weakening at all really until over 400*f depending on the metal (but a few metals like sterling will harden in the 4-500 range), to get most metals to weaken substantially you have to get them up in the 1100+ range depending on the metal so that it is annealed. for a hookah you would melt out the solder way way way before you hurt the metal at all
and for the glass, as long as its made right you will have zero issues with it