Well, the blue bottle was my blues – and the red bottle was what I made my bottle slide out of

Another great DIY project: making your own bottle slide out of an old wine bottle. Bottle slides, if you weren’t aware, are those great things bluesmen use to get the high lonesome sound out of a lap steel guitar.

There are obvious ways to make these things including a glass cutter or a cutting disc, but here’s the method Rober Johnson used at the crossroads.

This is just one of many ways to make a slide, another great one is the “Burning Twine” method. Legend says this is how a lot of the old bluesmen made their slides. Follow step one above “drink the contents” then find some old hemp twine, soak it in kerosene, wrap it around the bottleneck and light it on fire. Then after it goes out, plunge it into a bucket of ice water, and, it the theory is correct, it will break off cleanly and presto, you have a great authentic bottleneck slide.

SlidePlayer has more info for your reading pleasure.
via Craft