Heidi at Hands Occupied created this giant arrow sign. She'd be coveting a vintage arrow sign for ages, but wanted a cheaper alternative- not to mention one that's lightweight and lights up!
Materials one 30" x 40" piece of foamcore, one 22" x 28" piece of foamcore (the same thickness as the first piece), an X-Acto knife, a pencil, a ruler, school or tacky glue, small straight pins with flat tips, acrylic paint, a paint brush, a toothpick or nail, and enough LED string lights to fit along the perimeter of the sign.
You can make this any size you want, but these instructions will be for how to make a 92" long sign.
1. Cut out the arrow: using a pencil, ruler and X-Acto knife, carefully measure and cut your large piece of foamcore into 7 rectangles: 11" x 40" (1), 11" x 38: (1), 2" x 11" (1), 2" x 40" (4). Those 7 rectangles perfectly add up to a 30" x 40" inch rectangle, as shown in the first diagram.
2. Then use your other piece of foamcore to make a triangle for the head of your arrow and 2 inch wide rectangles to edge it. You don't need to do any complicated geometry here, just make the triangle about 14" tall.
3. Glue the 2-inch edge pieces all along the perimeter of your arrow. To do so, simply draw a line of glue along the top of your foamcore where you want to attach a 2-inch edge piece and place your edge piece onto the glue line.
4. Secure the 2" edging with straight pins by pushing a few straight through the bottom of the foamcore, through the glue and into the 2-inch edge piece of foamcore. This step is almost like constructing your arrow with wood and nails instead of foamcore and straight pins.
5. To form a corner, which you'll do for the butt of the arrow and the arrow's head, simply draw glue along the L-shaped corner where your foamcore comes together. Place the appropriate piece of foamcore, and then secure it in place on the two sides the glue was applied.
6. Since the arrow is so long, there may be a couple places where the backing of the arrow and the sides needed to be glued and tacked together. The trick there is to run glue along the appropriate edges, place the foamcore, and then tack the pieces together with two pins, forming an X inside the foam core.
7. Let all glue dry completely before the next phase.
8. Paint all along the outside and top edge of the arrow, leaving the backing and inside edges white to reflect as much light as possible.
10. Poke a hole in the bottom corner of your arrow with a straight pin and use a nail or toothpick to enlarge the hole.
11. Unwind your LEDs and feed them through the hole (you may need to feed two strands of lights through). To secure the lights, pin them into place with more straight pins. If the sharp end of the pins sticks out of the back, carefully bend down the pointy ends on the back side of the sign so they're flush with the back of the arrow.
12. Now just hang your arrow on the wall! If your LEDs are powered by AA batteries in packs that come with a slot for wall-mounting, mount the battery packs right next to the arrow so it's easy to turn on and off.