Over the summer, I spent a week in Burlington, Vermont at the Create, Make, Learn conference. It was an amazing week spent with fellow maker educators, and I learned so much from them. One of my goals for the week was to become more proficient designing for a laser cutter. While I had used lasers in the past for making fun jewelry projects and classroom signs for my colleagues, I wanted to try something a little more complex. An edge lit acrylic sign was the perfect starting point.
Edge lit acrylic is an easy way to make a very impressive looking piece of work. The basic process is pretty simple: get a piece of edge colored acrylic, etch a design on it that you want to light up, cut it to the size and shape you want, and stick it in a base with some LEDs. Presto! An edge-lit sign. Right? Riiiighhhhttt….
So, simple in idea, less so in execution. Turns out there are a LOT of factors to consider. The acrylic piece is the simplest of stages, but there are a few key points to remember when designing it. One of the first bits of advice I was given was to make the corners rounded – acrylic can be sharp when laser cut! The other advice I was given was to make sure that the light would have a path to follow through the acrylic. For example, if I am cutting out a shape that is 5 inches wide at its largest point, but I cut away all but two inches at the bottom where it will meet the lights, only that two inch width of acrylic will be lit. I needed to either cut the acrylic in a wedge shape so the light would flow from the smallest point at the base to the widest point of the design, or I needed to make sure the acrylic piece stayed the same width as the design all the way down. Since this was my first time working on this type of project, the simplest thing to do was to just make the entire piece of acrylic one width.
For my first design, I used lovely sheet of green edge colored acrylic to etch our school logo onto. I then cut it into a rectangular shape, with an extra inch or two at the bottom to fit into the base. That was the easy part. The next stage was a lot more time consuming and frustrating. I needed to make a base!
The base needed to do two main things. First, it needed to securely hold the acrylic sign piece upright, with as little wobble as possible. Second, it needed to house the LED light strip with as little light leakage as possible. I wanted as much illumination as possible to be directed into the acrylic itself, not lost around the edges. At this point, I was extremely grateful for my measuring tape and my digital calipers! Boy, is it important to get the measurements correct BEFORE you start firing up the laser.
For my base, I decided to stay simple and work in layers of wood. I was using 1/4″ birch for this part. First, I decided about how long and wide I wanted my base to be. It needed to be slightly longer than my acrylic piece, and wide enough to support the signage without tipping over. I also needed to make slot in the center of some of the layers for the acrylic to fit through, and I needed a cutout in the base piece for the LED strip. Time to fire up Illustrator and get to work!
I ended up creating four almost identical rounded rectangles from the wood to make my base. The first (bottom) layer was just a solid piece of birch cut into the rounded rectangle pattern. The second layer added a cut-out slot that started about a half inch from one edge of the rectangle, and continued all the way to the opposite edge. It was designed to be just wide enough to accomodate the LED strip, and the opening on one side allowed the cord portion to exit the base.
The next two layers were identical. They were two rounded rectangles with a slot cut into the center. The slot was just infinitesimally larger than the width and depth of the acrylic so that it would fit snugly into the slots without a lot of light leakage or wobbling. Once the cuts were done, it was time to assemble the base. The bottom layer and the second layer (with the slot for the LEDs) were glues together with some E6000 craft glue. The LED strip was then cut to length, and fit inside the slot. Once I was sure it fit, I peeled the backing off the self-stick LED strip and secured it to the base. The two identical slotted top pieces were also glued together with E600 glue. Because I wanted to be able to access the LEDs in the future if they shorted out, I did not want to glue the top pieces to the bottom pieces. Instead, a few pieces of double sided tape were sufficient to secure them without making it permanent.
Finally, the acrylic was inserted, and the lights turned on. I was rewarded with a lovely, green glowing SLAMS sign! Once I got it home, I added some metallic green paint to the base, and now the SLAMS sign lives on our secretary’s desk at school. I enjoyed making it so much, that I made a second SLAMS sign for my desk at work, and a purple dragon sign for my desk at home! Next time around, I may experiment with other options for the base. The design I created works, but isn’t the most elegant of solutions. We’ll see!