Introduction: LED Backlit Sign
Here are the steps I performed to produce this LED backlit sign. You can use this Instructable to make a LED backlit sign of your own design. This project was very time consuming and required multiple resources and equipment to complete. This should be treated more as a guide of steps involved as I explain the reasons why I did things the way I did. The sign is comprised of thin layer of walnut veneer glued onto a white translucent acrylic with a clear mirror-like epoxy finish. Under the acrylic, is a power supply and LED strip lights that are capable of multiple colors, mounted onto a backer board. The LED lights are controlled by an IR remote. The sides open to allow the light to spill out onto the wall.
½” Baltic Birch plywood
¼”-20 x 2.5” full-threaded flat head countersink screws, nuts and washers
5m – 300 LED RGB lights with remote (next time I would buy non-waterproof)
4-conductor phone cord
Adobe Illustrator or comparable software for vector file generation
Vacuum press to make the wide veneer if you can’t purchase it
CNC Machine or service
Laser Engraver or service (that accepts your material)
Small hand tools
Step 1: Sign Design:
I produced this sign for a basement bar for a family member. I found the clipart online for the “O’Leary “and converted it to vectors using Adobe Illustrator. I also added the “EST 2019” and “IRISH PUB” in a suitable font. I made a second file to cut the white acrylic with a ¼” wide outside border. This would provide a nice illuminated border around the sign. The sign can be a simple or as complicated as you like. I could now work on making the veneer, knowing how big I wanted the sign.
Step 2: Make the Veneer:
I wanted a dark wood for the sign. The darkness of walnut would be a good contrast to the white acrylic. I wanted the walnut to also be thin, so the lettering would be well defined. I needed a thin layer of veneer walnut, but it does not come that wide (24”) without costing more money than I intended to spend. I bought .020” thick walnut veneer in 4-foot lengths that were about 6” wide. I proceeded in cutting panels and splicing the edges until I had enough for the 21” x 24” sign. The trick is to cut the veneer with straight clean edges (with a veneer blade) and then joining the pieces with veneer tape until it’s + 21” wide. I then had to make a second layer with the wood grain perpendicular to the first layer. One layer was too thin. I joined the 2 layers with veneer glue in a vacuum press. Once the glue cured, I noticed the piece was very warped. I had to add a third layer with the wood grain in the same direction as the first layer. Like plywood, an odd number of layers is needed to prevent warping. Finally, I had my veneer; 3 layers and only about .060” thick. I sanded the surface and applied a light coat of stain to bring out the wood grain.
Step 3: Cut the Veneer and Acrylic:
I have a CNC that I built (see my Instructable), but right from the beginning I knew a laser engraver would do a better job cutting out the lettering. As an experiment, I epoxy glued walnut veneer to some acrylic and cut it out with the CNC. I was not happy with the cutter marks in the acrylic or the raggedness of the cut letters. The epoxy also gummed up the cutter quickly. There was no way the cutter would last for an extended cut. Cutting just the veneer layer with the CNC would risk ruining the veneer or ripping apart the thin sections between some of the letters. I found a business within an hours’ drive to cut the veneer and the acrylic. I didn’t want to lose the letter centers during the cutting process, (with the: O, e, a, 9, R, P, B) so I added ‘webs’ to the letters to hold them in place. The veneer and acrylic were cut quickly on the industrial laser and I was ready for the next step. I saved all the cut pieces to use later for positioning the letter centers. I finished up the veneer by cutting out the web of letter centers using a sharp knife. I labeled the backs of the letter centers and identified the tops to avoid mixing them up. I finished up the letters (and the letter centers) with a little sanding. The cut-out letters were also saved, to be used as a guide when gluing the letter centers onto the acrylic.
Step 4: Make the Backer Plate:
I cut out a backer plate to mount the LED and support the front portion of the sign. I used ½” Baltic Birch which is very flat and stable. The backer plate is the exact shape and size as the acrylic. The acrylic needed to be supported from the backer plate, so I picked locations close to the outside edge of the veneer for the support screws. I also chose locations for the support screws, so they would be hidden under the veneer. I also created an opening for the power cord for the power supply. I used my CNC to cut out the backer place. I cut the backer plate from the back, so I could add counterbores for the washers and nuts. I painted white the front surface and sides to provide a brighter surface for the LED’s to reflect off.
Step 5: Prepare the Acrylic:
With the backer plate as a template, I drilled holes in the acrylic for the screw supports. I countersunk the front face of the acrylic for the flat head screws. I roughed up the surface of the acrylic with 220 grit sandpaper. This would provide a surface for the epoxy to stick well (I hoped). I made sure the screw heads were below the surface of the acrylic and epoxied in the screw heads and fastened them in place with a washer and nut on the back side. I glued them in place because I didn’t want the epoxy leaking through the screw holes. I also didn’t want them rotating when I attached the backer plate. I also added a nut ½” from the end to act as a spacer for the backer plate. I put a thread locker on the threads to hold the nut in place.
Step 6: Attach the LED’s to the Backer Plate:
Place the cut veneer onto the painter backer plate and lightly trace all the letters and shapes. The outlined letters will be a guide for the LED strips. I laid out the LED strips in the Adobe Illustrator file knowing that I could cut the lights every 3 inches. I cut the LEDs at the appropriate locations and placed them on the backer plate. My design also allowed me to mount on the backer plate the controller and power supply in a non-visible location. I removed the adhesive backing from the LED strips and placed them in their location. I paid attention to the orientation of the LED strips to make sure the wire routing was always correct. The LED’s have 4 terminals on each strip (12v, G, R, B). Orient each strip so the wires don’t cross (12v, next to 12v or B next to B). I purchased waterproof LED’s because it was less expensive and more available. In hindsight, I should have bought the non-waterproof LED’s. It was time consuming removing the waterproof layer to access the solder points. I pre-tinned each solder point on the LED strip and I pre-tinned the jumper wires. For jumper wires I used 4-conductor phone cord. I branched off the power a few places, so the LED’s were not in one continuous strip. After soldering each LED strip, I powered it up to make sure all the colors worked. 200 solder points later it was ready. I did not trust the LED adhesive so once all the strips were soldered, I screwed in clips to hold the strips in place. I reserved a location for the controller and made a 3D printed part to hold the remote sensor.
Step 7: Glue the Veneer to the Acrylic:
I placed the cut veneer on the acrylic with clamps and inserted the cut out letters that were saved. I then glued (with E6000) the letter centers (for the: O, e, a, 9, R, P, B). Now comes the tricky part. The veneer would not lay perfectly flat and I wanted all the veneer to be glued as flat as possible. The epoxy is not very tacky, and it takes about 4-8 hours to set. I made a ‘pressure plate’ with my CNC machine to push down the high spots on the veneer. I mirrored the sign file and I added ¼” hole everywhere I wanted to push down on the veneer. I cut ¼” dowels all the same length and placed them in the holes. The dowels would hold down the veneer while the epoxy cured. I also added longer guide dowels to capture the perimeter and position the pressure plate. I applied a thin layer of epoxy onto the acrylic, placed the veneer, centered it, clamped it and applied the pressure plate. I used a limited amount of epoxy avoid flooding the surface of the veneer and accidently gluing the dowels from the pressure plate onto the veneer.
Step 8: Flood Coat With Epoxy:
Once the veneer was epoxied in place it was time to build up the layers of epoxy. I had a few veneer high spots due to missing a few locations with my pressure plate, but it would work out. I mixed about 1oz of epoxy per square foot of surface area of sign. It’s important to mix the epoxy thoroughly for it to cure properly. I should have mixed up 2 oz / square foot because I had to fill up the letters along with the surface of the veneer. Pour the epoxy onto the veneer and spread with a plastic spreader. I used an inexpensive paint brush and I poked the full surface of the sign. This helps even out the epoxy. Use the brush to also spread the epoxy onto to any dry edges, especially the outside acrylic border. I then sweep my hand under the acrylic edge to eliminate any forming drips. Let the epoxy level out and settle for a few minutes and then quickly sweep the entire surface with a propane burner to pop the air bubbles. Wait a bit and repeat with the burner. Don’t hit it too many times with the torch because the epoxy will start to boil. I then covered the project with a 2 inch clearance gap above the epoxy to prevent dust from flying onto the epoxy while it cured.
Allow the epoxy to cure, rough up the surface with 220 grit between coats and apply another layer of epoxy. I worked on the LED strips while the epoxy cured. Often the epoxy would find a porous spot in the veneer and create a low spot. It took about 4 coats to fill in the letters and eliminate the low spots. Use about 3 oz/square foot for the final flood coat. You should end up with a mirror smooth finish.
Step 9: Final Assembly:
With the LEDs in place and the epoxy cured, I mounted the veneer assembly onto the backer plate and attached washers and nuts to the stand-off screws. I tie-wrapped the remote sensor in place. I installed a 6” French cleat to the back for hanging. I added 1/8” thick pads to the back to allow for the French cleat. The back plate has an opening for the power cord and the plan is to place a power outlet in the wall aligned with the hole. Power it up and enjoy the multiple color.
Step 10: Conclusion:
This was a very labor-intensive project. The walnut veneer took many hours to create the width and build-up the 3 layers. The stripping of the waterproof layer on the LEDs and the soldering of 200 solder points was time-consuming. The multiple layers of epoxy took days to build up to the right level. After it all, I was very pleased with the results and the gift was well appreciated. Thanks for your time.
Participated in the
Make it Glow Contest