Homemade glass help

[goboard23]

Hey everyone,

So i have been making my own bongs, pipes, bubblers and such for quite awhile now. i started off with plastic getting better and better. i ended up making a bong out of a hershey park souvenier bottle (you know the ones that just look exactly like bongs. i know youve seen em) and i put my lifeguard cpr mask on the top which was amazing. it didnt just milk, it buttered. the smoke builtup enough to get a hint of yellow.

anyway, i recently bought myself a diamond grit covered drill bit for drilling holes in glass but i do have a hard time getting things airtight. i use a brass bowl that slides right into the whole but have never successfully been able to get it airtight. currently, it works fine but it still isnt airtight and i always try and make my pieces as nice as they can be. does anyone know of and rubber rings i could use that would go around the bowl and fit snugly in the hole?
also, the brass bowl works well and although alot of people think brass gives off harmfull toxins, it doesnt. atleast not with a butane lighter. butane lighters dont burn hot enough to cause the brass toxins to come of of the brass. however, it gets very dirty and is a bitch to clean so if anyone had any ideas on another alternative to a brass bowl, like how to make a stainless steel or glass on it would be greatly apreciated