124: Light-Guiding Lucite

Two different materials, lit from the bottom with an LED strip.

I’ve worked with lit acrylic in the past, but I ran into some issues getting a full 2-foot long piece of acrylic to light up when lit from one edge. I knew there were materials that were made to respond better to being edge-lit, but didn’t have any on hand to test at the time.

That changed when I was given a spare piece of Lucite Light Guide Acrylic—Thanks Mark! This material is described as follows:

Developed specifically for edge lit applications, including lighting and signage, this LGP continuous cast acrylic is formulated with evenly dispersed illuminating particles to provide bright, even illumination. Suitable for use with LEDs, fluorescent and cold cathode light sources.

Naturally, I took that description to mean it would solve my specific problem better than a normal piece of cast acrylic would. I didn’t stop to consider that it might not behave the way I expected, which meant it was a tiny bit of a surprise when it didn’t behave the way I expected.

The lucite lit up all the way down the 2′ sheet.

My plan was to carve a repeating pattern of surface engravings and full cuts out of two 12″ by 24″ sheets of acrylic, identical except that one was this specialized Lucite and one was the generic cast acrylic I regularly use for unlit projects. With an unquenchable thirst for geometry, I settled on Tetris, again, and included a 24 inch measurement on one side of the engraving. This was so that I could figure just how far up the material the light would reach, a measurement I only thought was necessary because my previous efforts seemed to dim half-way through.

Surprisingly, the acrylic also lit up brightly from end to end.

But once I was done processing both sheets of acrylic and plugging the LED strips in, I realized the ruler was pointless: both sheets lit up from end to end beautifully! I expected the Lucite to light up with no issue (after all, it’s made to do exactly that) but I didn’t expect the other piece of cell cast acrylic to do the same. I’m assuming now that my previous efforts were hampered not by the fact that it wasn’t using specialized light-guiding material, but by the fact that it was fluorescent blue acrylic rather than clear.

The acrylic surface barely lights up at all.

Still, there was a notable difference between the Lucite and the plain acrylic: the surface brightness. The cell cast acrylic only lit up on the edges, with each vector line and raster fill a bright white but the surface itself as clear as can possibly be expected.

The lucite’s entire surface lights up.

In comparison, the Lucite’s unmarred surface was foggy, reducing contrast between it and the engraved art. That must be what those “evenly dispersed illuminating particles” were for! With the contrast actually hurt by the semi-lit surface, I think I prefer the look of the plain acrylic to the Lucite, but your preference will depend entirely on the art you’re trying to light and how you want it lit. Definitely take price into account, though, as the Lucite will run you $36 where the same size in plain acrylic is only $19.

The (nearly) 24″ ruler on the engraving was rendered moot. Still looks pretty cool!