I wanted to make an all glass bong out of an awesome bottle I have, and being in a country with no headshops, I made this downstem/bowl combo. Its going to be semi-permanently fitted to the bottle under friction and I plan to use a second finger-hole on the side of the bottle to clear smoke. You may use this method if you're in a similar predicament as I am, otherwise it's better to shell out the cash for a machined/blown downstem and bowl. Things you need: a small bottle - the kind that vanilla essence and food coloring comes in glass cutter - 2-3 dollars at any hardware store glass tubing which almost fits in your bottle's mouth - I cut off the end of a 12mm test tube and used it sandpaper - 80 grit will do the job First you're going to have to cut the bottle in two using this technique: score (scratch) the bottle all around in one line. Then, heat the bottle along the scratch with a candle flame for about 40 seconds. After that, quickly run an ice cube over the scratch. The extreme temperature change should crack the bottle neatly in two. This method works when cutting test tubes as well, but since test tube glass is very thin, it rarely cracks neatly. If you want more info on this method, search for vids on youtube. Second, grab your sandpaper and sand the contacting surfaces (in my case, the outside of the glass tube and inside of the bottle mouth) carefully, taking care not to put too much pressure on the fragile glass tube. Occasionally lubricate the sandpaper with a little water. Keep going until you get the glass tube and bottle to slide into each other in tight fit. Take your time and push the glass straight into the bottle mouth, because if you go at an angle, the tube may crack. I filled mine with water and there were no leaks. To finish, sand down any rough edges the you might get your stoned ass cut on .