Slide guitar is a style of playing that appears so simple and sounds so sweet, I imagine we have all been driven to go out and get ourselves a slide at some point in time. But that first time you put on your slide and go to town, how quickly reality sets in. It's no wonder our slides end up in the pockets of our cases, destined to never see the light of day. I thought I'd give some tips and a quick video to help you get your slide chops sounding the way you want, so dig out that slide and start wood shedding!
Open Tunings vs Standard Tuning - I personally like to play in standard tuning and Open E (E,B,E,g#,b,e low to high). On lap steel I typically play in Open A (A, C#, E, a, c#, e low to high). Playing in standard can make things seem easier, you can relate to the notes as when you normally play without a slide, but it can be limiting to produce chords with the slide and doesn't have a distinct voice, as certain open tunings do. Open tunings will sound really full and bluesy, but there will be a bit of a learning curve getting to know the location of the notes and their shapes to play chords, scales, and licks. If you are trying to go for a specific artist's sound, you may explore the tuning that artist likes to use for a particular song.
Slides - These days you can find custom made slides in about any shape, size, and material. Glass, pyrex, chrome plated steel, brass, and porcelain are probably the most common materials. I personally like a heavy wall glass slide. I primarily play on electric and I find that I can get a nice tone and retain speed with a heavy glass slide. I have used brass and chrome plated steel for acoustic, but lately have settled on glass, (hand made by Don Lennon and St. Louis Slides) for everything. One of the most sought after slides is probably the vintage "Coricidin" glass bottle made famous by Duane Allman. I have played with many copies of these bottles that are available from slide manufacturers and have been a bit disappointed, but recently had the opportunity to play a real Coricidin bottle and it was heavier and sweet sounding. Keep an eye out for vintage bottles at local antique stores, estate sales, and yard sales! I normally play with the slide on my pinky, and I like a slide that is not too long and fits snuggly up to my knuckle. A lot of people play with the slide on their ring finger, and there may be an advantage to this while playing in open tunings. The bottom line is, try different ways and figure out what works best for you! Think of it as trying different sizes and thicknesses of picks or exploring different string gauges.
Playing Basics - At this point I would recommend you use the video to help get you started. I personally find it's a lot easier to watch someone do something as apposed to reading about it. Here are some tips to think about as you go. Lay your slide parallel with the fret and directly over the fret for proper intonation. Keep a finger or multiple fingers on the strings behind the slide to help dampen the strings and reduce noise. This was a huge breakthrough for me in the beginning! Be aware of the amount of pressure you use with your slide and your dampening fingers. You don't want to push too hard to cause the slide or the string to touch the fret board, but firm enough to make a clear note. Reference the area you are playing to a particular spot on the slide. For example, if I am playing on the sixth string, I try play that string with a specific spot on the slide and move the slide across the fretboard to play other strings on the same spot. I also angle the slide to accommodate the radius of the strings and fretboard. Try using your fingers instead of a pick. You'll be able to keep unwanted noise to a minimum by having your fingers dampen the strings you are not wanting to ring out. Try sliding up to the note you are targeting and work on a slow, even vibrato. Vibrato is a hard technique to master and takes time.
Set Up - You may find that your favorite guitar may not be so great for slide. This can be a great opportunity for you to look into some cool, old guitars that maybe don't make the grade for everyday playing due to high action or tiny frets. I love combing the net for old Teisco's, Harmonys, Silvertones, Danos, and other lower budget vintage instruments that might make good slide guitars! The weirder looking the better, and I have found that the pickups are, a lot of times, a bit microphonic and gnarly sounding. Perfect for slide tones! I prefer heavier strings for a more solid tone and usually use .011s on my electric slide guitars. Some shorter scale guitars may merit .012s. I like my action a bit higher, usually around 5/64" from the 12th fret to the string. This really isn't that high, but allows me enough room to play well with the slide and my fingers. I also keep the nut slots cut a bit higher than I would for normal playing, and I always keep my neck straight.
Experiment as much as possible and have fun! Try different tunings, instruments, slides, pedals, and anything else you can think of. If you hit a wall, stop and pick something out to listen to. I find the greatest inspiration when listening to other players, especially someone I haven't heard in a while. Here is a list of popular slide players, their tunings, and some cool links.
Ry Cooder - Ry Cooder is a true stringed instrument aficionado! I happened across a cool web site on all things Ry which includes an in-depth look at his instruments and tunings. Check out Open D ( D, A, D, f#, a, d, low to high), and Open G ( D,G, D, g, b, d, low to high) to work on Ry's more popular tunes.
Duane Allman, Derek Trucks, and Warren Haynes - Duane is most famous for playing in Open E (E,B,E,g#,b,e low to high). Duane did play some in standard tuning and Open G (D,G,D,g,b,d low to high), as well. Derek uses Open E (E,B,E,g#,b,d low to high) primarily, and Warren mainly uses Standard, though he does tune down 1/2 step, a lot. Here is a cool article from Guitar Player October 1981, by Arlen Roth on Duane. http://www.duaneallman.info/duaneallmansslidestyle.htm
Elmore James - A huge influence on Duane, Elmore also played in Open E (E,B,E,g#,b,e low to high) and Open G (D,G,D,g,b,d, low to high). Check out this short biography on Elmore by the Rock&Roll Hall of Fame. https://rockhall.com/inductees/elmore-james/bio/
Robert Johnson - Robert is all over the place and used many tunings, as well as a capo, though Open G (D,G,D,g,b,d low to high), is a common one. Here is a pretty in-depth study into the style of his playing, tunings, and chord shapes. http://www.guitarplayer.com/artist-lessons/1026/10-things-you-gotta-do-to-play-like-robert-johnson/11906
Rory Gallagher - Rory primarily plays in Open G (D,G,D,g,b,d low to high), though he does play in standard tuning on recorded parts, at times. Here is a cool interview with Rory from 1991. http://jasobrecht.com/rory-gallagher-the-1991-interview/
Sonny Landrith - Sonny plays in all the tunings! Ok, maybe not but you can keep up to date on what he uses on each song while on tour via his website.