He hammers a couple of nails about 18 inches apart on a 2x4 and stretches a wire between them. Behind on of the nails is another nail - but not up as high. He brings the wire down to the low nail and anchors it, then grabs a glass Coke bottle and wedges it under the wire between those two nails - you can vary how much tension is in the wire between the two main nails depending on how much you shove the bottle under that wire. He then nailed a pickup underneath the main wire - plug it in, and it’s read for some gut-bucket slide.
Like I said before, I have seen them made but using the side of a house, not a 2x4. They have a cute name, like whangdoodle or diddley-bob or something, but basically they are a primitive, 1-string slide. But they can make music…
