Slides are typically made from glass, metal, or ceramic, and every slide has certain qualities that might be preferable for a particular application. “Application” is the key word here, as, for example, a heavier slide tends to works best on a guitar with fatter strings and tall action, while a lighter, thinner-walled slide is usually better for guitar with skinnier strings and low action. The style of music and type of guitar you play are obviously important factors in choosing the right slide, so try different types and see how they work for you. Whatever you pick, make sure it fits your finger snugly and doesn’t fall off when you hand is pointing south, but not so tight that you can’t slip it off easily—especially if you like to switch between slide and fingers in different sections of a song. Here are a few things to consider about how a slide’s size, shape, and material affect tone:
In general, thinner slides offer better control because they are lighter and they keep your finger closer to the strings. If you’re a beginner, start thin and work your way up. Thick slides can be harder to control, making it easy to “overshoot” the targeted fret when sliding around the neck—although they tend to produce a fatter sound, and are the way to go if your guitar’s setup has been optimized for slide with higher action and heavier-gauge strings.
Most slides are basically straight tubes, but some have a flared shape that can help your vibrato and make it easier to navigate different neck shapes and fretboard arcs. A flared profile can also minimize buzzing and allow for easier angling when playing in non-open tunings. Then there are domed slides, which have a rounded surface on one end and may have certain benefits for players who like to finger notes behind the slide.
If you’ve ever played slide with a Coricidin bottle (or the Dunlop model 272 equivalent), you can thank Duane Allman for bringing thin glass to masses—although he certainly wasn’t the first to use a medicine bottle for slide playing. Glass is the material of choice if you want a smooth feel and warm tone with lots of harmonics. Glass slides are available in a wide variety of styles and thicknesses, and along with glass, Pyrex, and borosilicate, some are crafted from recycled wine, brandy, and olive oil bottles. Thicknesses can range down to 4mm, so be careful not to drop a thin-walled slide while walking to the stage. Good advice if you’re going with glass is to pack a spare.
Brass or steel slides typically deliver a harder, brighter tone, which might be the ticket if you want more edge in your sound. However, metal slides that are highly polished and/or have chromed surfaces can be good choices if you want a little more heft than glass provides, and don’t want to worry about breakage. There are also metal slides with multi-point interior gripping—like that of sockets used for working on machinery—and these might be preferable in some cases over a smooth-walled slide.
Glazed porcelain falls somewhere between glass and metal and can be a great alternative for some players. The scientific rap is that sound from the glazed surface travels into the underlying porcelain, producing a tone that is actually brighter than glass, but smoother than metal.
There are no rules when it comes to choosing a slide. Try as many as you can and see what works best. Slides are relatively inexpensive, so pick up a few and see what sticks after using them for a while. There is also a wealth of information about slides from the websites of manufacturers such as D’Andrea, Diamond Bottlenecks, Ernie Ball, Fender, Jim Dunlop, Latch Lake, Mudslide, Planet Waves, Rocky Mountain, Rock Slide, and Steve Clayton. And, if all else fails, get an empty bottle of Mateus Rosé or a piece of motorcycle handlebar and make your own custom slide!