Things You'll Need
Large shadowbox (any size you like, such as 36 x 48)
Chalk or pencil
Drill with bit slightly wider than light sockets
Spray paint in desired sign color
Strands of LED Christmas lights, all one color
Duct tape or clear packaging tape
Create your own illuminated sign using a large shadowbox frame and several strands of holiday lights. Choose a frame with a durable backing board, such as wood or fiberboard -- you'll have to drill holes through it to attach the lights. The back of the shadowbox becomes the front of your sign, so if the shadowbox has hanging hardware attached to it, remove it.
Cover a work surface in a well-ventilated area -- you may want to work outdoors -- with newspaper. Set the shadowbox atop the paper, upside down. If the shadowbox has a glass cover, remove the glass first.
Sketch the outline of the text or graphic layout for your sign on the back of the shadowbox, taking up most of the available space to make the sign as visible as possible. Use a pencil or chalk to sketch the basic design, or print out your idea, enlarged to actual size, at a print shop.
Determine how far away you'd like each LED light within your sign, such as 2 inches from one bulb to the next -- the closer the lights are together, the more obvious your design will be, and the more strands of lights it will take. Mark the light bulb layout by making a dot every 2 inches -- or another designated distance -- over the entire design. Use a ruler to keep the distances consistent.
Drill out holes for the lights at each marked dot using a drill bit slightly wider than the light sockets on the light strands. Use a bit as close as possible to the actual socket size for a snug fit.
Sand the shadowbox sides and back gently with a fine-grit sanding block to smooth it, removing any splinters or snags made from drilling. Flip the shadowbox over to sand any splintered wood visible on the inside as well. Remove all the dust with a rag, then flip the shadowbox back over so the back is on top.
Shake a can of spray paint for a minute or two, then paint the back and sides of the shadowbox, keeping your arm in continual motion. Paint parallel overlapping lines while holding the can 12 inches or so from the shadowbox. Start each burst of paint before the shadowbox and end slightly after to avoid blobs of paint. Allow the paint to dry completely, then apply a second coat for better coverage. Paint it a third time, if desired.
Plug light strands into one another if your sign design requires more than one strand.
Prop the shadowbox up vertically so your design is aligned correctly. Determine if you want the plug end to dangle from the left or right side of the sign, and then position the plug in the chosen area. Press the light bulb nearest the plug through the back of the sign, which is the front of the shadowbox, through the drilled hole nearest the plug. The bulb end should be sticking out of the front of the sign.
Push the bulb next on the light strand into the second hole in your design, next to the first. Continue pressing bulbs in consecutive order through their respective holes on the sign until all the holes are filled.
Test the sign by plugging it into a nearby outlet. If any of the bulbs or an entire strand aren't working, replace the bulb -- if possible -- or the entire strand, until all lights illuminate. Unplug the sign.
Position the sign so the back is exposed, showing all the cords. Tape the cords to the sign back using small strips of duct tape or clear packaging tape, keeping the tape away from the bulbs. Align the extra cord near the plug end so it travels along the bottom inside edge of the sign and then dangles from a corner. Tape the cord inside the back of the sign so it stays in this position.
Read the Christmas light packaging to determine how many lights are on each strand and how long the strands are ahead of time; this way you'll know how many strands you need to complete your design. If the packaging is long gone, count the lights and measure the strands.
Use the sign by leaning it against a wall atop a cabinet away from pets or children, or mount it on a wall using picture-hanging hardware attached to wall studs or wall anchors.
Use modern LED lights, rather than old Christmas light strands, in your sign. LED lights emit far less heat than old-fashioned light bulbs, so they are less likely to burn items nearby.
Test the light strands beforehand to make sure they work properly. If you are using the sign outside -- even in a covered area -- use only light strands designated for outdoor use.
Spray paint only in a well-ventilated area while wearing a dust mask to avoid breathing in fumes.