To make this key you will need:
- 1.5 (or just 2) 4' x 8' sheets of cardboard
- Plenty of hot glue and a hot glue gun
- Sharp razor blade with extra blades
- Long rulers/ straight edges
Step 1: Plan and Sketch
After laying out your drawings, it is time to scale them up and onto the cardboard. The easiest way I found is to divide up the cardboard into chunks as shown in the smaller drawings. For example, the key "head" is shown in the drawings as being 32" x 28", so simply draw a rectangle on the cardboard that is the same size. After you have drawn out all of the basic shapes with rectangles, then go back in to put in the details such as rounded corners or the teeth of the key. After your first key is drawn and you feel happy with it, it is time to cut.
Important: When dealing with corrugated cardboard, it is necessary to take note of the direction of the corrugation. In this case, we want the corrugation to run perpendicular to length of the key faces.
Step 2: Slice and Dice
The 'key' to making kickin' cardboard objects is the miter joint. This is preferable to the butt joint, especially in the case of cardboard because the miter joint won't show the corrugation inside. Seeing the corrugation is what makes cardboard things really look like cardboard (cheap looking). To do this, every cut needs to be made with the blade at 45° or less. This is when it becomes very important that your razor is brand new and very sharp.
Otherwise, this step is fairly simple. Cut out your drawn key while maintaining a blade angle of 45°.
While cutting this way, you will create a piece of cardboard with a larger side and slightly smaller side. The larger side will always be the outside of your object so remember to cut 45° from the proper side.
After cutting out the first face of the key, you can use it as a template to trace the other side and then cut it out as well.
Step 3: Prepping the Grooves
Step 4: Gluing the Grooves
Only glue the grooves to one side at this point.
Step 5: Completing One Side
Cut several 2" wide strips across the grain (as shown) using the same 45° method. Try to get strips as long as you can make. After cutting the strips to the right size, peel off the inside layer of paper while keeping the outside and corrugation. You may not need to take off the paper on every edge (some edges are straight) but you couldn't go wrong doing so.
After your strips are cut and floppy, work your way around the outside, gluing the 2" strips to your base (the face that has the grooves glued). Remember that where the teeth of the key are you will have to make the strips 1" wide instead of 2".
If your strip is not long enough, simply tear the two inside plies out of the last half inch. Then you can glue the single ply on top of the beginning of the next strip to make for a seamless look.
This would also be a good time to add a few support pieces to the inside. I made tiny triangles whose width is 2" minus the thickness of two sheets of cardboard. I believe cardboard is 1/4" thick so each support would be 1 1/2" wide. Glue these inside wherever you think it necessary.
Step 6: Add 2nd Face
When you reach the end of the grooves, you will notice that the cardboard is different lengths. You will have to carefully trim everything down to the right length before finally attaching it.