In this Instructable, we're going to design and build a light-up "On-Air" sign for our makerspace. We shoot video in our space, and we need a way to let employees and guests know when we need things quiet on set. Inspired by some classic molded plastic "on-air" sign designs, Andrew came up with a laser cut and engraved light, and experimented with bending acrylic. Follow along and make one with us. We'll attach our project files here and upload them to github so you can make your own at home.

Supplies

6mm baltic birch
1/8" acrylic (we used cast, extruded might be better for this)
Battery powered RGB LED strip light
3" PVC pipe - or print a 3" cylinder (STL attached to this project)
Heat gun
Wood glue
220 grit sandpaper
Diffuser material - we used some out of a broken monitor.

Step 1: Prep, Design, and Cutting Out Parts

Andrew sketched up his design and got to making vectors to cut out on the laser. All of our files for this project are attached. We cut all the parts out on our 100W CO2 laser, but you can get away with a 40-45 watt laser, or even print these vectors out to use as a template on a scroll saw.

We've also attached a vector for the radius of the acrylic bending jig. You'll need to cut out, glue, and stack a bunch of those together to build the jig.

This design assembles with some wood glue and clamps, then uses a single screw to hold the sign together. This makes for easy disassembly for battery changes and maintenance.

Step 2: Glue Up and Acrylic Bending

This design uses a number of stacked and glued together plywood parts. Glue together the top and bottom stacked panels as shown in the photos. Also glue the spacer bars that receive the acrylic onto the back plate. Lastly glue in the small panel that holds the sign together with our 'keystone' screw.

Stack your small radius pieces into a tower that creates the radius of our bending jig. Glue and clamp them together. You can use brad nails to assist with this glue up. Sandwich the tower as shown on an appropriately sized frame made from scrap plywood as shown in our photos.

With the acrylic bending jig assembled, and after waiting for glue to dry - center and clamp your 1/8" cast acrylic onto the jig, and begin to gently heat it with a heat gun over the radius until it starts to become pliable. Slowly and carefully bend it down as it becomes soft, and take the heat off of it. Continue to hold it in place until it cools. Repeat for both sides.

***Note: Not all acrylic is created equal. We had cast acrylic from one source that cracked and crazed badly when bending. The specific cast acrylic we're used here worked fine for us, but you may have better luck using an extruded acrylic for thermoforming.***

Step 3: Engraving and Final Assembly

With the acrylic bent, it's time to put our text on it. We engraved the reverse image of some simple "ON AIR" text. Of course you can use any text or font that you'd like.

The body of the lamp was assembled. We wrapped the strip lights around a 3D printed tube sized perfectly for the light - but a section of 3" PVC pipe would be more than sufficient for this project. We've attached our STL here though in case you want to print a tube.

We felt it needed some better diffusion, so we sanded the inside of the acrylic to spread out the light a little better - but it wasn't enough. We disassembled a broken LCD monitor and used the diffusion material from the back of the panel to disperse the light a little better.