This is how to make your own professional-seeming glass guitar slide from a bottle to get that nice bluesy sound, or to play any number of other types of music. This is a very easy method of making a great tool for guitarists, and makes great, cheap gifts for your guitarist friends.
Step 1: Gather Materials
One bottle. This should have a very pronounced neck, unlike some beer bottles which just taper slightly to the top. The project will work best if the neck on your bottle has a long, straight section, like a wine bottle.
Glass Cutter. If you don't have one, get one. I got mine for i think $3.50 at the hardware store, and its very useful if you're into DIY. This is essential to the project.
Sandpaper. You could rub the glass on the wet sidewalk, this also works. I use a combination, since the sidewalk is rougher than my sandpaper.
You may also want gloves, since there is a guaranteed potential for broken glass. hearing protection is also advised, since there is also a potential for loud noises.
Step 2: Cut around the neck
A glass cutter does not actually cut glass, rather it scores a "weakest link" line into the glass which, when the glass is broken, will redirect the direction of the breaking along the scoring line.
To use your glass cutter score a line around the neck applying pressure with the cutting wheel along the glass, like in the picture. Try to make just one, straight line to get a good, clean cut.