So i just bought this titanium nail that fit my bong and i was wondering if the heat from the nail could break the downstem of my bong?
It shouldn't break your bong glass unless you got a really cheap bong. Any decent borosilicate bong can handle the conducted heat from a hot nail.
If you have a female joint and a male nail (meaning that the nail sits inside the glass rather than around ) then there is always a chance of your glass breaking because titanium has a greater expansion rate with heat than glass. Not saying its gonna happen instantly but i wouldnt gamble.
I'm not sure what the nail is for but if it's to hold the bud I have a better solution. Grab some aluminum foil and poke holes in it with a needle. Then fit it on the bong, that's what I do. I've heard tho something about the metal releasing some shit that can be bad for you. But then again that's what they do with hookahs/water pipes and they haven't turned into feral aluminum monsters so what's the worst tht could happen.
Yeah its a male joint buts not a cheap bong. It goes into glass and the glass is pretty think, and i hardly ever get the nail glowing red