Yes, you can play slide on a fretted guitar. However, when you are first starting out using a slide on your cigar box guitar, I think you will find it a lot easier if that guitar is fretless. This is because initially it’s very hard to stop fret buzz until you get better control of both the slide and the fingers resting on the string behind that slide.
However, supposing you only have a fretted instrument and are struggling, there are a couple of things you can try:
Raise The Action of The Cigar Box Guitar
It’s much easier to avoid fret buzz when playing slide if the strings are further from the fret wire. If you are building your own guitar, consider aiming for a slightly higher action. If you raise the action just a tiny bit you will still be able to play it with your fingers as a fretted instrument without too many intonation problems ( See this article: https://beginnercbg.com/guitar-tuning-and-intonation-problems-how-can-i-fix-this/)
Buy ( Or Make) A Nut Raiser
There is something you can try as a temporary and removable solution to this problem and it’s called a guitar extension nut. You might be able to buy one of these in your local guitar shop like I did. It’s a piece of shaped metal that fits over the nut and under the strings.
I did actually go in to buy a fretless cbg, but ended up with a 4-string and the guitar extension nut. I just fell in love with the sound of the 4-string and couldn’t justify buying that and a fretless cbg.
Unfortunately the one I have bought is designed for a six stringed neck so is a bit too wide but I find it works OK as long as I have the excess metal on the side of the neck facing up into the air. There is then no chance of my fretting hand catching on the excess metal.
It’s a little annoying to install in that I need to slacken off all the strings quite considerably to slide the metal under, but once in place it does a good job of raising the string action and it was inexpensive, just a few pounds.
Those of you that are good with working with metal could make one of these fairly easily I would think. Although the one I bought has shallow ridges cut in for the strings to sit in, they don’t line up with my 3 strings. However that doesn’t seem to be a problem. I suppose I could saw it to make it shorter and then re-cut the grooves but it works well enough without all that effort.
Why Is It Useful To Play Slide On A Fretted Guitar?
As you get better at playing slide, you will probably find, like I did, that having frets becomes less of a problem. You don’t get fret buzz to the same extent, partly because your slide finger gets better at knowing how much pressure to apply. It’s also partly due to the fact that your fingers can mute the strings behind the slide more easily as you get practice more.
The ability to switch between playing slide and making shaped chords on the same instrument is really useful. You can even do it within the same song if you don’t have the nut extension installed.
Having the ability to make shaped chords can add flavor to your playing that you will not be able to achieve if you are using a fretless instrument.
For inspiration, watch someone like Justin Johnson or Steve Arvey on YouTube to see what I mean.
In Summary
You can play slide on a fretted guitar if the action is not too low and you practise a bit to get good control of the slide and the fingers that sit behind the slide to avoid unnecessary fret buzz.
Further Reading: Can I play Slide On An Acoustic Cigar Box Guitar?