This article was taken from the original CigarBoxGuitars.com archives.
Wine bottle with long neck
Dremel Rotery Tool with grinding stone bit (optional)
1. Take a piece of masking tape and wrap it around the base of the bottleneck, making sure one side of the tape makes a perfect circle. This will serve as a guiding line for the glass cutter.
2. Using the glass cutter, scribe a solid line around the bottleneck, following the masking tape’s guide line. Make sure the line does not break or get choppy by going up or down the bottleneck.
3. Remove the tape.
4. Take the bottle to your kitchen sink and run very hot water over the scribed line on the bottleneck for at least 2 minutes.
5. (Here’s the trick) Then change the tap water to cold and run bottleneck under the stream AND TAP ON THE SCRIBED LINE WITH YOUR FINGER or the metal ball end of the glass cutter. Slowly rotate the bottle, allowing the water to hit every part of the scribed line. You should eventually hear or see a crack along the scribe. The bottleneck may even fall right off. (You may want to place a kitchen towel in the sink before this step to keep a falling bottleneck from breaking.)
If there is no crack, repeat steps 4 and 5.
6. If it cracks but the bottleneck does not fall off, take hold of the neck and snap it off (just like breaking a chicken’s neck).
7. (optional) Dry off bottleneck and use Dremel Rotery Tool grinding bit to smooth the edges of the cut glass. -or- If you want to keep the slide “authentic” to blues history, take it outside and smooth the edges on your sidewalk. Be careful not to chip off too much in the process.
Viola! You have your own true Blues bottleneck slide.
Don’t get mad if your first one doesn’t break right. This happens from time to time. Keep practicing.