Making a Glass Capo for Fretless Guitar

The idea that you could use a Glass Capo on a Fretless Guitar has the ring of “Chocolate Teapot” about it. Yet Ned Evett made one and used it extensively on his “Glass Guitar (Vol 1)” album. So we set about building one of our own from readily available items. Thanks to Steve at Promenade Music in Morecambe, UK, for help in sourcing the items. He took a look at Ned Evett’s video which shows the capo and Steve supplied a TGI 2778 six string guitar capo (£3.95) and a No. 210 Dunlop Tempered Glass Slide (£7.95). So total cost £11.95

Glass capo parts

Now this is only going to work on a guitar with a flat fingerboard, glass is ideal of course, but any fingerboard material that has a radius is just not going to work. Additionally you have to take care with string thickness, but first let’s take a look at how to put things together.

Method of construction

As the normal capo has to pass through the glass slide you will first have to cut off the metal ferrule from the end of the capo with a single eyelet.

Glass capo ferrule cut

Next loop the single eyelet over the capo rod.

Glass capo rod

It should look like this, you did cut the ferrule off the right end, didn’t you?

Glass capo hooked on

You could seal the end with a small flame, but it will sit inside the glass slide, so should not fray.

Glass capo insert

Now pass the rubber and rod part fully into the glass slide.

Glass capo inserted into slide

Hook the opposite end eyelet on to the rod and you are done!

Glass capo finished

Oh, then attach to a fretless guitar with a flat fingerboard….

Glass capo attached

The glass capo should be attached with the rod facing you, that way it is easier to adjust.

Glass capo fitted

You can quickly slide the capo to anywhere on the neck, or slide it over the nut when not in use.

The slide works best when the guitar is tuned to an open chord, for a run down of these see: Alternate Tunings for Fretless Guitar.


If the above pictures are a little hard to follow, here is a little video of the whole event….

String thickness

When I first tried using the capo the guitar had a heavy 6th (053) string, which raised the capo at one end meaning other strings were not clamped tightly and buzzed. So I would have to restring the guitar. So I drew a few diagrams just to see where the problem was.

Flat wound 12’s

This is a diagram of string heights, a typical set of flat wound 12’s. The line above the strings shows how the capo would lie on the strings, the diagram is not to scale as far as string spacing but it does show the string sizes accurately and why there was buzzing on the middle strings. If you had to look at the strings using just the top three and bottom three, it would be pretty consistent but as I’m not a glass blower to create a bevelled capo, another solution has to found.

String heights 12's

Round wound 10’s

Just for consistency, I drew the same diagram for round wound 10s, same problem.

string heights 10's

A solution

So could we have a set of strings that will look flat to the capo? The answer is yes! You can buy individual strings and build up the set 11 – 16 – 22w – 28w – 34w – 40w, a little light on the fifth and sixth strings but fully workable. Given that the tuning will be open, the fifth and sixth strings could be tuned higher if they appear too slack.



I ended up using D’Addario NYXLs from treble to bass: 0115-016-022w-028w-034w-040w tuned to Open G7 G-B-D-G-B-F  and might move the 40w up to 41w in future. The tuning is described in Alternate Tunings for Fretless Guitar.


Here’s a video showing Ned using the Glass Capo on his Fretless Guitars:


Using a capo with a Fretless Guitar


Alternate Tunings for Fretless Guitars More DIY Projects


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