Introduction: How to Make a Backlit LED CNC Sign of a Logo

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This was created for a fund raiser for our local All Out Baseball league. I donated my time to create this for them. In this video I show you how to make a CNC sign of a logo and backlight it with LED strip lights. The total material cost was about $90 including the 1/8" bit to cut out the logo and back. I used a CNC to cut this out but you could use a scroll saw and a table saw or even a hand saw.

If you find this helpful or you have questions please leave feedback on my video. You can visit my channel to see my other videos at https://youtube.com/udoit2

The materials and tools used (some tools are optional, i.e. paint by brush rather than paint by hand):

The filming was performed with the following equipment. I am able to record continuously for 8 hours straight with the USB Battery tied to the GoPro over a USB cable:

WARNING!!!!

It is expected that you will follow all safety precautions and read the owners manual of any tools prior to operation. This also includes the operation of hand tools. Always wear eye protection. Also consider the risk of soldering and inhaling of fumes and the dangers associated with a hot element on a soldering iron which can not only burn you but also start a fire if left unattended. These are only ideas to help foster thinking more about personal safety as well as operating in a safe environment. You are responsible. Consider reading the MSDS prior to ordering any paints, cleaners, solvents and solder. For instance, if you have an allergy to latex would you also have a reaction if you spray painted with it?

Step 1: Cutout the Logo or Pattern in 1/4" Sheet of MDF

Cutout the logo or pattern either by hand or by CNC (if you do this by CNC obviously there is tooling involved that will not be covered here). Either way you do it just make sure that you have enough relief for the LED lights and the wiring. You'll see what I mean later when I show you how I wired it up. I'm using RGB LEDs and this requires 4 wires (3 power and 1 ground). That is quite a bit of wiring required and you'll see where this was challenging for me at a couple of spots.

This sheet of MDF cost me $7 at the time in January 2017.

Step 2: Cutout the Back of the Sign

Cutout the back of the sign matching the exact maximum height and maximum width of the logo. I was able to use the other side of this MDF since my sign was less than 24 inches and this sheet was 2 foot by 4 foot.

Step 3: Sand the Edges of Every Piece

Sand the edges of every piece using a fine grit sandpaper like 220 or 400. This will help to get rid of any loose fibers (afterall this is called MDF which is medium density fiberboard). You will not get them all off unless you are a total perfectionist. Just make it look clean until you are satisfied.

When I sanded I did the edges along the surface of the edge with a small piece of sand paper. I would then do the corner around the edge by holding the sandpaper at 45 degrees to the corner and I would go all around the part. This would clean up any fibers that were sticking out at the corner and make it look like it was a crisp cut.

Step 4: Trace Logo Outline Onto Back of Sign

Place the logo cutout on top of the back of the sign. With a pencil carefully trace out each cutout around the edges. This will be used at a later point for gluing the cutout pieces to the back of the sign.

Step 5: Place the Cutouts in Center of Each Traced Area

This is only a step to check for your satisfaction. Place the pieces in the center of each trace and eye it up to verify that it is in the center. Then by hand lower the logo onto the piece without actually touching it to simulate the way it will look after the piece is complete. Does it look good?

Step 6: Verify Operation of LEDs and Measure Thickness of LED Controller

Plug in your LEDs and verify that they operate fully. Next using a tape measure or calipers measure the thickness of the LED controller. The LED controller will be glued to the back of the sign towards the bottom and you need to make standoffs that are taller than the thickness of the LED controller (including the infrared LED that protrudes the controller).

Step 7: Cut Dowel Standoffs

Using a saw cut the dowel standoffs to a height that is larger than the controller measured in the previous step. I am cutting 9 to place in all four corners than in strategic locations to add strength to the logo. I'm using a miter saw with a stop added so that I will have consistent thickness. The number of standoffs you need will depend upon the complexity of your logo. This is 1 inch dowel I purchased from our local craft store.

Step 8: Place Standoffs, Trace and Glue in Place

Place the standoffs in the locations where it looks like it will need support. Trace each one then glue them in place. I used a cyanoacrylate glue from Hobby Lobby. Do not place the standoff where the LED controller will be mounted. Allow room between the standoffs and the edges where you will mount the LED strips.

Step 9: Center Pieces in Place, Trace and Glue in Place

Center the pieces in place and trace their outline. Using glue (I used cyanoacrylate glue) affix each piece in place as shown.

Step 10: Paint the Sign With Sandable Primer

I used a white sandable primer and a pneumatic sprayer. You could use a spray can. You can also paint by hand using a brush.

Step 11: Sand the Face and Edges

Using a fine grit sandpaper, sand the faces and edges of the logo and the back. The primer will help to show any fibers that you didn't get at first and will make it easier for them to come off with the sand paper. Consider wearing a respirator while doing this since fine particles will be released into the air that you could inhale.

Step 12: Paint the Outline of the Cutouts

Here is the video queued at this point: https://youtu.be/7hMtsDaBHkA?t=3m26s

Here I'm painting the outline of the cutouts with an orange using the airbrush. I'm not going for perfection and I like the way the airbrush pattern shows how it fades away from the cutouts. I'm using acrylic paints thinned with windex about 1 to 1 ratio and mixing it by hand with the end of a brush.

Step 13: Sand the Logo and Edges and Paint

I sanded the logo that I applied the primer to. I sanded the face and the edges. Then I thinned acrylic paint with windex using a 1 to 1 ratio. I used white paint here and applied it to give a nice look to the surface. Clean out your airbrush thoroughly after you are done using it. You can use a spray can or paint by hand instead.

Step 14: Prepare the Surface of Logo Cutouts and Paint

Prepare the surface of the primed logo cutouts by sanding the surface of each cutout. Then apply white paint with a brush for the backing color and sand it after it is dried. Then apply your color onto the top of the cutouts being careful to ONLY paint the top of the logo.

Step 15: Test LED Placement

Using tape and the LED strip temporarily affix it in place and turn it on. Then Flip the logo over onto the back and plug it in and turn it on again. Make sure it looks good prior to going onto the next step. You will get to see a preview of what it will look like. But it is only a preview because after you are done it will look much better.

Step 16: Cut LED Strips to Length and Glue Into Place

Cut the LED strips to length along the spots that you are allowed to cut, which are clearly marked on the strip. Choose the best locations for the strips and glue them into place. I used E6000 Industrial glue which holds very well. You CANNOT rely on the backing of the LED strips because the tape is horrible and doesn't work. Make sure that the ends of each strip are visible so that you can solder in the next step. If there is any overlap you may need to add an insulator with electrical tape or glue.

This is the video queued to the mounting of the strips:

https://youtu.be/7hMtsDaBHkA?t=5m04s

Step 17: Solder the Ends of Each Strip With Wire

Here you have to follow the pattern throughout all of the strips. It is best to purchase wire that is RGBBlack meaning one wire is Red, another is Green, another is Blue and another is Black for ground. Tin the ends of each wirestrip with solder. Then cut the RGB wire to length, strip the ends, tin the ends of each wire and solder it into place. Start with the strip that has the power connected to it first and connect it to the next closest strip. Remove the soldering iron and plug in power to the controller and test. After you test the LEDs be sure to unplug power from AC and unplug power connector from controller. Repeat these steps over and over until all LED light strip segments are connected together.

The last step is to glue the back of the LED controller onto the sign. I glued it at the bottom middle of the sign. Even though the infrared receiver is obstructed by the front of the sign the infrared light from the remote controller still finds its way to control it from across the room.

IMPORTANT: When you test this make sure you test Red, Green and Blue independently. If you fail to do this you may not discover that you have a wiring problem until you already glued wires in place.

As you continue through with the soldering glue the wire joins with E6000 Industrial or similar type of glue. E6000 is a rubber type of cement but it is very strong. You can remove it with dental instruments if you have to in order to repair a connection. Prior to gluing just make sure that all connections were properly soldered and tested. Follow through with this process until all are connected together. You can see that there is one area where there is not a large relief for running the wire. In this case I split the wire into two and ran two wires on one side and two wires on the other side so that you wouldn't see the wiring from the front of the logo.

Step 18: Test Your Work

Flip the sign over and place it on top of the back. Plug it in, dim the lights and give it a test.

Step 19: Prepare to Mount Logo to Back of Sign

Place the logo on top of the back. With a pencil trace the standoffs as best as you can. Just get a couple of the edges. It will be very tough to get a pencil in all the way. Drill a hole in the center where each standoff was traced into the back. The hole must be big enough to accept a wood screw. but small enough that the head will hold the back. The wood screw will be countersunk into the back of the sign.

This the video queued up to this step:

https://youtu.be/7hMtsDaBHkA?t=5m49s

Step 20: Mount the Logo to the Back of the Sign

Place the logo flat on a surface with a towel so it doesn't get scratched. We do not want to damage the sign. Place the back of the sign on top of the logo in the proper orientation. Using a small drill bit by hand mark the center of each hole onto each dowel standoff. Then with a drill bit sized properly for a pilot hole for your wood screws drill it to the length required. You only need to go so deep so mark the drill bit with electrical tape or use a drill bit depth gauge affixed to the bit. Only drill one hole at a time and install the screws after each hole is drilled. This way it ensures proper alignment of the screws. Countersink each hole on the back of the sign using a countersink bit or a larger drill bit. Just do it by hand since MDF is very fragile. The screws should be flush with the back after they are installed.

The last step (not shown in photo or in video) is to mount hooks to the back and use picture wire so that it can be hunt on the wall. To do this I used 1/4-20 nuts/bolts to secure the picture hangers like this picture hanger here. But, I did not use the wood screws supplied. Instead, I used the nuts and bolts and drilled through the back of the board in an inconspicuous area and mounted the hangers. Then I attached the cable across so that it would hang perfectly on the wall.

Step 21: Step Back and Look at Your Work

After you are done stand it up and turn it on. You should be pleased.