The shop I work in sells a lot of industrial equipment. One of the things we sell is a set of valve cocks for reading water levels in a glass tube mounted next to a vessel (Sight or Gauge Glass, if you're savvy). The valves we get come with a clear piece of soda lime glass tube which is just adorable compared to the big thick borosilicate ordeals we actually use. Since the work our crews do is generally high pressure, the soda lime tubes get thrown out and we replace them with the good stuff when we sell the valve sets.

I had been eyeing them for awhile. A clear glass tube had to have some potential in a lighting project, right? Well, one day, I thought I'd rescue a few of these from the trash, and I made this guy with it.

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This one was neat at night, but not bright enough to show well in daylight.

The top and bottom (painted black) are cheap plastic test tube drying racks that I shoved some of the bin-destined sight glasses into. The existing holes were too large for the 5/8" diameter sight glass, but just barely too narrow if I slipped some sight glass gaskets onto each length. This required widening the holes a bit, but nothing my Dremel couldn't handle. Once I was sure of a tight fit on each side, I filled the tubes with polyfil (stuffed animal entrails make great diffusers). My plan was to send light through the tubes and have it mix in the foam inside. I attached a D1 Mini and cut some lengths of LED strip. I put a couple LEDs at each end of each piece of glass, as well as a strip of about a dozen LEDs under each row of white plastic drying pegs in front. (they made less great, but still decent diffusers).

I wasn't sure what to expect when I switched it on, so I was pleased when light sprang forth from the strips and illuminated the entire tube. Unfortunately, once the sun came up the next day, I realized this would only ever be an accent lamp. There just wasn't enough space beneath each glass to cram enough light in there to be useful. That was okay, though - I like creative accent lamps.

I programmed some effects into the controller to take advantage of the unique shape. Each of the tubes and pegs could be a different color, and the top and bottom could be different from each other to create faded gradients. I made sure the top and bottom didn't create opposing colors in the same tube at the same time, washing them both out. Complimentary colors turned out fine. Sadly, I don't have any video of it animating, but it made for a pleasant yet subtle curiosity.

It was a fun project, and it definitely had a unique look, but it never created enough light to be anything more than decoration.

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It could change its colors, but it couldn't change the colors of anything around it.

I may utilize the cheap glass for another project in the future. I hate throwing anything away that could be useful, and I never seem to run out of ideas to reuse things. For now, however, this project has been retired to the parts bin.

This article is part of a series on LED Art as I attempt to document all of the different LED projects I have built over the years.
More will be added as time goes on. The list of currently available articles can be found here: https://dzw.zentormey.com/tag/leds/