U.S. Air Force’s official survival handbook describes the signal mirror as “probably the most underrated signaling device found in the survival kit.”
Whether you need a mirror for Ten Essentials Kit or you just want to be sure you look sporty on the trail, a signal mirror is a handy trail aid and it is easy to make. I get my first mirror with an official BSA wash kit, but it wasn’t long before it got too scratched up to use. So it became time to make one.
Here are the simple steps needed to build a signal mirror:
- Two pieces of glass mirror (preferably 3 to 4 inches is ideal)
- Super Glue
- A straight–edge
- A pencil with a good erasers
- A sharp knife with a good point or a nail
Making a Signal Mirror
- Using the straightedge and pencil, draw an X, corner to corner on each mirror
- A the center of the X on both mirrors, scrape off a 1⁄8-inch-diameter circle of the paint with the point of the knife
- Make sure that the holes are in the same place so that when you glue them together, they match.
- Clean up the holes using a pencil eraser. There will still be some glossy stuff on the glass that comes off best with an eraser and some elbow grease. Make the edges clean because this is your “aimer.”
- Next, glue the two mirrors together, making sure to match the holes on the back to see through. Keep glue away from the hole.
Using the signal mirror
- Use the mirror to reflect sunlight onto a nearby surface like a raft or your hand.
- Slowly bring the mirror up to your eye, while making sure that the reflective surface is not obscured by your fingers or a hat.
- Tilt the mirror up toward the sun (not directly into it, though), until you see a small bead of light in the back mirror. This will be on your cheek or clothing.
- Once you’ve found the bead of light, move it toward your intended target. Keep the bead of light in view as you do this.
To aim it, hold the mirror with one hand and extend the other hand in front of you. Tilt the mirror until its reflected light fills your empty palm. Make a V with your illuminated fingers, then sight through the V toward an aircraft.
If your mirror has a mesh material in the mirror’s central hole, this is a retroreflector; it reflects light through the hole at an angle that is supplementary to the sun’s angle of reflection on the mirror. Looking through the aiming hole, shine the mirror on a nearby object, like your hand, and find the bright dot on the retroreflective material in the aiming hole. Then move the dot to the distant object you want to signal.
Make a Giant Fold-up Signal Mirror
A 2–by–2 foot square mirror would be bulky, but you can make this huge mirror that fits into a backpack with these instructions. Use standard 1–by–1 foot decorative mirrors (approximately $2 each at a discount store).
Cut a 1–by–1 square foot piece of 1/2–inch plywood (if it’s thinner, it may warp). Drill five holes: one in the center, the others 1½–inches from each corner. These are to accommodate the little “jiggers” (hammer–in permanent nuts, as shown). Use ¼–inch coarse threaded jigger with a wing bolt and a 1½–inch washer plus a homemade rubber washer from an inner tube. Buy an extra jigger and put it near the center (but offset) and on the other side of the plywood.
You’ll find it will hook up perfectly to a standard camera tripod, which will let you, hold the signal on someone you know is there…until they notice you.