Intro: Low Profile, Portable Light Box
What is a light box?
Light Boxes are flat boxes with internal lights and a translucent top material. Light should be evenly distributed on through its top material to provide illumination or light contrast to items placed upon its surface. Light boxes are used for a variety of purposes including developmental education activities.
This light box was designed for use by children with developmental disabilities. This target user group motivated a few of the design characteristics. We wanted a relatively lightweight and portable device because it would be used in a variety of locations by educators, therapists and parents. The box was sized to be 18” x 24” to be small but still allow for reaching and upper extremity range of motion as a part of therapy or intervention. LED rope lights were used for their long life and compatibility with a low profile form factor.
Step 1: Construction Overview
Prep Time: 1 ½ - 2 hours
Assembly: 1.5 hours
Seal: 30 minutes
Wait: 4 hours
● 1/8” Birch plywood
● 1”x4” Birch
● 1/8” white acrylic sheet (translucent)
● 1/8” colored acrylic (for letters and numerals)
● wood screws (#8 x 1 ½”)
● wood glue
● aluminum tape
● LED rope light (12-16 ft)
● eyelet hooks- ¾”
● polyurethane wood sealer
● heat gun
● table saw
● miter saw
● drill press
● staple gun
● paint brush
To avoid eye damage, wear safety glasses while cutting wood, plywood, and acrylic with the table saw and miter saw. To avoid unwanted stains and adhesion to your surroundings and self, practice caution and precision while using the wood glue and polyurethane sealant.
Step 2: Rip the Sides to a 3’’ Width
Using a table saw, rip the wood used for the sides of the box
to a width of 3”. We purchased 1” x 4” so ripped it accordingly; based upon the need to add a top and bottom, we do not think a shorter frame would work, but a taller frame would work fine (i.e., 4”)
Step 3: Cut the Boards Into Four Pieces for the 18” X 24” Frame
To configure the sides of the box, 45 degree angles are cut
into each 24” and 18” lengths of the 3” wide board. The angle cuts must have opposite orientations on the two ends in order to configure a box frame
Step 4: Cut Dado Grooves Into Frame Boards for Bottom Board and Top Acrylic
Measure the thicknesses of your plywood and acrylic for the top and bottom of the lightbox so you can ensure the thicknesses of the dado grooves will accept these items. Using the table saw, set it to cut a ⅛” depth into the board, and the dado grooves ¼ “ from the edge as pictured above (left). Slide the boards lengthwise across the table saw as pictured above (right). Cut two grooves into each board as shown.
Step 5: Drill Holes in Top Board (for Handle and Light Rope)
Mark the center of one of the 24” boards for the LED rope.
Mark two smaller holes for the handle rope (4” lengthwise from each side of the center mark). A ½” drill bit is used for the outer holes. The size of the center hole depends on the size of the connectors at either end of the LED rope because one end must pass through this clearance. In our case, a 1” forstner bit was used for the center hole.
Step 6: Measure and Cut Bottom Plywood Piece
Measure out 17” x 23” wood piece of ⅛” thickness. To cut, set table saw alignment to 23” and slice through the entire sheet. Then set the alignment to 17” and saw through. Sand down the edges of plywood.
Step 7: Reflective Backing
Measure and cut aluminum tape such that there is a ⅛” gap between the end of the tape and the end of the boards. Remove the backing and carefully place the tape along the length of the boards to minimize wrinkling of the tape.
Repeat the above process for one side of the plywood backing, leaving a ¼” plywood edge around the entire perimeter of the board. This is to allow the board to fit into the dado grooves. Make sure to line the pieces of aluminum tape up so there is little or no gap.
Step 8: Assembly
Use corner clamps to line the bottom and side pieces into flush corners (no overhang between edges). With the bottom clamps firmly in place, loosen the side clamps and remove the sides. Use wood glue to glue the sides together. Use tape to hold the glue in place and let it sit overnight. Then using a staple gun, secure the edges. Make sure not to glue or staple though the dado groove, because the top acrylic and plywood base must fit in the groove. We decided to glue 3 sides together and use a screw attachment for the 4th side (top piece).
Step 9: Sand
Once assembly is complete, make sure to sand all the edges of the box using sand paper. Be careful to not blunt the corners of the light box.
Step 10: Stain
Once sanding is complete, blow away all sawdust on the box. Using polyurethane stain, seal each side of the box, including the top. When painting the pieces, make sure that no paint drips into the slots cut for the acrylic top.
Step 11: Insert Handle on Top Side
Don’t attach the top side to the board yet. Take a rope that is over 12 inches. Knot the two ends of the rope after inserting them through the first and third holes made in step 4, making sure that 12 inches of rope protrudes between these holes to act as the handle.
Step 12: Insert Back Wood Piece
Insert the wood back in the structure by sliding it into the grooves.
Step 13: Drill Holes for Hooks and Attach Hooks
Cup hooks are used to secure the LED rope lights. On the inner side of the left and right panel, measure evenly four spaces so that the hooks can be situated upright. Drill each until the height is the same as the hook length. Drill bit will depend on the hook diameter. After drilling, twist the eyelet hooks by hand until they curve upright from the back wood panel. Do this for all the hooks.
Step 14: Attach Lights and Tape Down to Back Piece
Slide in the back wood piece and line with aluminum tape. Make sure not to cover the outer edges so that the piece can slip in easily into the dado grooves. Pull the lighting through the top panel hole, and line the interior in zig-zag form, pulling it over the hooks. Make sure that the light is evenly distributed so that adjacent tubes are not touching. Secure areas down with aluminum tape, covering over the resistors and not the actual lighting.
Step 15: Measure and Cut Then Insert Acrylic
Measure and mark a 17” x 23” region of ⅛” thick acrylic. In our example, we used a white, translucent acrylic, which allows light to be transmitted from the LED’s, but also allows it to be dispersed. To cut, set your table saw alignment to 23” and slice through the entire sheet. Then set the alignment to 17” and saw through on the other side. Sand down the edges if burrs remain.
Step 16: Attach Top Acrylic Sheet
Only after the back panel, light rope, and acrylic front are inserted into the light box should you attach the final frame piece. Align the dado grooves making sure that the lid is facing the correct way; it will only fit this way. If positioned properly the lid should fit snug on the front and back panels and line up with the right and left existing corners. Then, use a drill bit of the same size as your screws to drill into the right and left side panels of the box. The holes should be made about a half of an inch from the top and centered right and left. It is important that the holes go through the side panel and into the top frame piece. Use right angle clamps to hold the wood in position if needed. Take your screw and drill it into the hole you just made. The Head of the screw should be almost flush to the sides of the box. Repeat the same process for the other side.
Step 17: Laser Cut Letters Template
Attached is a pdf template of the letters, numbers, and math operators for use with the light box. If you don't have access to a laser cutter or cnc locally, you may order online using this file through a service company like Ponoko https://www.ponoko.com/