I have heard urban legends about people using tiny regular mirrors for visual signal, but don't have personal experience. For people considering tiny regular mirrors, please go out and practice trying to hit stuff at a long distance with a tiny regular mirror. For example, you could have a buddy drive a mile away. I'm not talking about hitting a building that's 100 yards away and easily viewable. Note that you can't see where the reflection is hitting if it's hitting at a far distance. It's really a guessing game if you don't have an aiming device.

If you have the opportunity to plan beforehand, I recommend getting a dedicated aimed mirror. My confidence is about 10 times higher with an aimed mirror. If you really need a mirror to save your life, you're going to be glad to have one. They're not that expensive and not heavy.

Originally Posted By: hikermor
Thinking about the general question, I believe there is one environment where a signal mirror might be less effective - at sea or a similar body of water, at least for other vessels at your level. This is because it is fairly common at sea to experience "mirror flashes" from other vessels. With this in mind, aim several flashes in succession at an intended target - that would be unusual and should get attention.


Even then, a signal mirror is unlikely to work. While on a beach a month ago, I was imagining someone stranded out there on a kayak. When I paid attention, I realized that there were thousands of strong reflections coming off the water. The reflections while on a boat were even worse. I couldn't imagine anybody detecting a mirror flash as being distinguishable from all the other reflections. If a mirror flash were noticed, it would be mostly dumb luck I think.
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