Shorter slides with a snug fit offer more control than long slides because they allow the finger they’re worn on to bend. This allows you to move the slide more easily along the strings. Photo by Andy Ellis

Laurel or Hardy?
Weight is the next consideration and, not surprisingly, preferences vary wildly. Obviously, long slides weigh more than short slides of the same material, diameter, and wall thickness. It’s the latter measure that’s most important when considering a slide’s weight. Regardless of what a slide is made of, more mass equals more weight. It’s that simple.

Some players dig a thick, heavy slide. Lowell George, the guitar powerhouse who led the original lineup of Little Feat, used an 11/16" Craftsman socket wrench, available for about $6 at any hardware store. In contrast, Allman’s Coricidin bottles were thin-walled bantamweight containers, and vintage examples today occasionally sell for $200 on eBay.

A heavy slide will pin the strings with less effort and move along the neck with less resistance, with the slide’s weight helping momentum. This can make the slide’s motion a bit smoother and aid in slide vibrato—gently shaking the slide back and forth over a fret to make a note shiver. On the con side, a heavy slide can be harder to hold in place and control. Thinner, lighter slides must be pushed down a bit harder against the strings to make notes sound correctly and may glide less easily over the strings, especially on a beginner’s hand. Effects like slide vibrato and hammering will also require more work at first. But, again, thinner, smaller slides ultimately offer a greater degree of control.

Eventually, though, all the physics of performing with a slide become second nature. So whether to pick a Stan Laurel- or Oliver Hardy-weight slide is ultimately also a matter of personal taste and comfort. Whatever feels easy and natural is always the best choice, and unless you’re buying vintage Coricidin bottles, it’s easy to afford a few appealing slides and experiment until a No. 1 emerges.

Golem or Terminator?
The next choice is material. Will it be glaze-finished clay or gleaming chrome or steel? Dark brass or reflective ceramic or glass? Or, if you’re really old-schooling it, like Fred McDowell early in his career, perhaps a steak bone? Each type of material and its density will inform your tone and approach.

Unless you’re buying vintage Coricidin bottles, it’s easy to afford a few appealing slides and experiment until a No. 1 emerges.

Let’s leave animal parts, pocketknives, beer bottles, Zippo lighters, wine glasses, et al. for another conversation. Metal slides are the most popular, with steel, chrome, and brass leading the pack. Steel and chrome slides produce the brightest, most screaming tones and can be acquired at any guitar shop, which is a plus if you’re on tour and lose your favorite slide. Think of the zinging, searing sound of Johnny Winter’s slide playing and you’ve got a fix on the voice of steel or chrome.

If you find metal appealing, but desire something that sounds less bright, brass and bronze fit the bill. Brass and bronze slides also tend to be a bit heavier than steel and chrome. Explore all the options. The late bluesman Iverson Minter, better known as Louisiana Red, was a fiend for both distortion pedals and metal slides, and tried every kind of metal tube he could lay his hands on, from thick-walled to skinny, and from aluminum to nickel to zinc. On a trip to Germany, he was invited to tour a metal distribution center, and Red asked his host to cut off a few inches of every tube in the joint that fit his pinky.

Fans of metal slides often carry their slides in their pockets along with coins and keys, so the metal will get scars that add character when applied to guitar strings. Some players even leave their slides outdoors in all types of weather to achieve a worn patina they believe will increase friction and make for a grittier tone in their slide attack.

A shorter slide can even be used for fretting an additional note in a chord. Photo by Andy Ellis

Glazed clay, ceramic, or glass slides are also terrific options. All three provide a smooth surface that glides comfortably over strings with little resistance. (Although some specialty versions of these slides offer a sandpaper-like surface on at least one section of their curvature for a grittier sound.) Since they are less dense than metal, they all sound warmer than metallic slides.

Elmore James played a glass slide—often an old bottleneck, sawn or cleaved with heated wire from a wine bottle. (Modern roots player Tony Furtado has a tutorial on making a bottleneck slide on YouTube, searchable as “Tony Furtado - How to make a Bottleneck Slide.”) So check out any of James’ classic versions of “Dust My Broom” to get an earful of how powerful a glass slide can sound on an amplified acoustic guitar, and we’ll return to him in a few moments.

In recent years, ceramic and glazed clay slides have come increasingly into vogue. Perhaps that’s because they can be given attractive color schemes. Like glass, they produce warm sounds, and the thicker their walls, the darker their tones—at least to my ears. And to my hands, they also feel supple and easy sliding against the strings.

While ceramic, glass, and clay all yield kinder, gentler tones than metal, they can also break when dropped. Not a problem with steel, chrome, brass, or bronze. And glass slides with thin walls can shatter during boisterous playing. That’s why jazzman Sonny Sharrock ditched glass slides for metal early in his career, although Sharrock also defied convention by palming a steel-guitar-style tone bar, rather than performing with a conventional tube-shaped slide on one of his fingers.