Signal Mirror

[Tony Fischer]

Not exactly sure this counts as MYOG, but since it took some screwdrivers I'll count it as such!

Dont want to argue whether one should carry a mirror. I choose to do so because I like having one for signaling, tick checks, and the occasional personal grooming. I have carried an Adventure Medical signal mirror for a while but I find they scratch easy and do not have a great reflection.

I found a much better option – a platter from a bad hard drive. I pulled two out of a laptop drive recently. They are very reflective and VERY lightweight. This one weighs in at only 4 grams. If you have any bad hard drives laying around, open it up and give it a try.

[Dan Yeruski]

What material is it made of and if it's plastic will it scratch easily as your of the shelf signal mirror? try scratching both to compare. Thanks for the tip.

[Greg Mihalik]

Tony,
Yes, great tip!

I was skeptical at first because I like the "sighting" center on the typical signal mirror but was pleased to find that the hole in the platter serves the same function.

By looking through the hole and reflecting the sun onto the first finger of my other extended hand I can quickly place the "shadow" created by the hole on the tip of the finger. Then by moving slowly to keep things centered, if I place that finger tip on the target I get excellent alignment, even at very oblique angles.

Thanks.

[Mobile Calculator]

…

[Greg Mihalik]

I just did a quick and dirty comparison between a CD and a hard drive platter. The CD doesn't even come close.

My "target" was the center of a shaded porch about 50 yards away. It was nearly impossible to see the reflection created by the CD. The image from the hard drive platter was very well defined.

It will take a two person team with radios to perform a long distance test – greater than 1000 yards – but I am pretty confident how the CD will fare. (It will be interesting to see how the hard drive platter compares to a signal mirror.)

And this is understandable: the CD is a 2nd surface device with very little attention to flatness. A hard drive platter is the opposite: first surface and Very flat.

[Mobile Calculator]

…

[Dave Heiss]

Tony,

Have you noticed any oxidation or discolorations yet on the hard drive platter? I know there are ferrous materials used in hard drive construction and I'm wondering if (and for how long) yours will stay bright now that it's out of the casing.

[Greg Mihalik]

Dave,
I've had a hard drive platter sitting out for at least 6 years and it looks like new.

[Tony Fischer]

The one I showed in the picture has been open sitting in my bookcase for at least 5 years with no signs of oxidation.

One other comment I would make is some platters are made of glass, others metal. I would be sure it is not made of glass. You should get a metallic sound when you gently strike it if it is metal. I would not pack a glass one for obvious reasons.

[Joel Hulett]

The hard drives of old used to be made out of pure platinum. They are hard to find as they were quickly recycled. The new generation, for those less geek minded, are platinum plated aluminum. Lighter and faster than the old drives. If the surface platinum is not penetrated it will stay shiny for a very very very very long time. Platinum, like titanium is very chemicaly inert. Not edited for spelling sorry.
Excellent repurpose btw
Joel

[David Thomas]

+1 to Tony.

> my kit has a similar setup with an blank CD that is silver shiny on both sides.

Roger: since it is reflective on both sides, you can multi-task by shaving while signaling your rescuers?

[Mobile Calculator]

…

[Author]

Posts